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1.  Perioperative visual loss after spine surgery 
World Journal of Orthopedics  2014;5(2):100-106.
Perioperative visual loss (POVL) is an uncommon, but devastating complication that remains primarily associated with spine and cardiac surgery. The incidence and mechanisms of visual loss after surgery remain difficult to determine. According to the American Society of Anesthesiologists Postoperative Visual Loss Registry, the most common causes of POVL in spine procedures are the two different forms of ischemic optic neuropathy: anterior ischemic optic neuropathy and posterior ischemic optic neuropathy, accounting for 89% of the cases. Retinal ischemia, cortical blindness, and posterior reversible encephalopathy are also observed, but in a small minority of cases. A recent multicenter case control study has identified risk factors associated with ischemic optic neuropathy for patients undergoing prone spinal fusion surgery. These include obesity, male sex, Wilson frame use, longer anesthetic duration, greater estimated blood loss, and decreased percent colloid administration. These risk factors are thought to contribute to the elevation of venous pressure and interstitial edema, resulting in damage to the optic nerve by compression of the vessels that feed the optic nerve, venous infarction or direct mechanical compression. This review will expand on these findings as well as the recently updated American Society of Anesthesiologists practice advisory on POVL. There are no effective treatment options for POVL and the diagnosis is often irreversible, so efforts must focus on prevention and risk factor modification. The role of crystalloids versus colloids and the use of α-2 agonists to decrease intraocular pressure during prone spine surgery will also be discussed as a potential preventative strategy.
doi:10.5312/wjo.v5.i2.100
PMCID: PMC4017302  PMID: 24829872
Perioperative visual loss; Ischemic optic neuropathy; Central retinal artery occlusion; Cortical blindness; Posterior reversible encephalopathy; Spine surgery; Prone positioning
2.  Positioning patients for spine surgery: Avoiding uncommon position-related complications 
World Journal of Orthopedics  2014;5(4):425-443.
Positioning patients for spine surgery is pivotal for optimal operating conditions and operative-site exposure. During spine surgery, patients are placed in positions that are not physiologic and may lead to complications. Perioperative peripheral nerve injury (PPNI) and postoperative visual loss (POVL) are rare complications related to patient positioning during spine surgery that result in significant patient disability and functional loss. PPNI is usually due to stretch or compression of the peripheral nerve. PPNI may present as a brachial plexus injury or as an isolated injury of single nerve, most commonly the ulnar nerve. Understanding the etiology, mechanism and pattern of injury with each type of nerve injury is important for the prevention of PPNI. Intraoperative neuromonitoring has been used to detect peripheral nerve conduction abnormalities indicating peripheral nerve stress under general anesthesia and to guide modification of the upper extremity position to prevent PPNI. POVL usually results in permanent visual loss. Most cases are associated with prolonged spine procedures in the prone position under general anesthesia. The most common causes of POVL after spine surgery are ischemic optic neuropathy and central retinal artery occlusion. Posterior ischemic optic neuropathy is the most common cause of POVL after spine surgery. It is important for spine surgeons to be aware of POVL and to participate in safe, collaborative perioperative care of spine patients. Proper education of perioperative staff, combined with clear communication and collaboration while positioning patients in the operating room is the best and safest approach. The prevention of uncommon complications of spine surgery depends primarily on identifying high-risk patients, proper positioning and optimal intraoperative management of physiological parameters. Modification of risk factors extrinsic to the patient may help reduce the incidence of PPNI and POVL.
doi:10.5312/wjo.v5.i4.425
PMCID: PMC4133449  PMID: 25232519
Spine surgery; Complication; Position; Nerve injury; Visual loss
3.  Visual Field Defect after Cardiac Surgery: The Striking Role of Interdisciplinary Collaboration 
Perioperative visual loss (POVL) is a potentially devastating complication that can occur following ocular or nonocular surgery. The leading causes of this disease are retinal vascular occlusions, ischemic optic neuropathies, and cortical blindness. POVL pathogenesis is strictly influenced by surgery, anesthesia, and patients' comorbidities. We report of a 55-year-old caucasian man who presented with complaints of sudden painless loss of vision and unilateral campimetric deficit. We recorded a preserved visual acuity but at fundus examination a bilateral ischemic optic neuropathy (ION) was suspected. Our hypothesis was supported by uncommon and peculiar visual field defects and a history of cardiovascular surgery shortly before was a striking data. When we examined his medical records we found strong accordance with what is reported in literature to be risk factors for postoperative ION development. He presented intraoperative hypotension, anemia, and hypothermia, he was older than 50 years, and surgery lasted for more than five hours. We are currently monitoring his visual acuity and visual fields which remain unchanged. As there is no proved therapy for such severe adverse events, we recommend intraoperative check of blood pressure, blood loss, and body temperature, associated with repeated eye checks and patients' interview.
doi:10.1155/2015/904528
PMCID: PMC4685447  PMID: 26770856
4.  Perioperative visual loss with non-ocular surgery: Case report and review of literature 
Indian Journal of Ophthalmology  2014;62(4):503-505.
Perioperative visual loss (POVL), a rare but devastating complication, has been reported after spine, cardiac, and head-neck surgeries. The various causes include ischemic optic neuropathy, central or branch retinal artery occlusion, and cortical blindness. The contributory factors described are microvascular diseases and intraoperative hemodynamic compromise. However, the exact association of these factors with post-operative blindness has not yet been confirmed. A case of POVL with caesarian section surgery is being presented. The visual loss occurred due to a combined occlusion of central retinal artery and vein. The causes, presentation, and risk factors of POVL after non-ocular surgery are being discussed.
doi:10.4103/0301-4738.116464
PMCID: PMC4064236  PMID: 24008804
Caesarian section; combined occlusion; non-ocular surgery; perioperative visual loss
5.  Perioperative visual loss in ocular and nonocular surgery 
Incidence estimates for perioperative vision loss (POVL) after nonocular surgery range from 0.013% for all surgeries up to 0.2% following spine surgery. The most common neuro-ophthalmologic causes of POVL are the ischemic optic neuropathies (ION), either anterior (AION) or posterior (PION). We identified 111 case reports of AION following nonocular surgery in the literature, with most occurring after cardiac surgery, and 165 case reports of PION following nonocular surgery, with most occurring after spine surgery or radical neck dissection. There were an additional 526 cases of ION that did not specify if the diagnosis was AION or PION. We also identified 933 case reports of central retinal artery occlusion (CRAO), 33 cases of pituitary apoplexy, and 245 cases of cortical blindness following nonocular surgery. The incidence of POVL following ocular surgery appears to be much lower than that seen following nonocular surgery. We identified five cases in the literature of direct optic nerve trauma, 47 cases of AION, and five cases of PION following ocular surgery. The specific pathogenesis and risk factors underlying these neuro-ophthalmic complications remain unknown, and physicians should be alert to the potential for loss of vision in the postoperative period.
PMCID: PMC2893763  PMID: 20596508
perioperative; postoperative; vision loss; ocular surgery; nonocular surgery
6.  Ischemic Optic Neuropathy Following Spine Surgery 
Perioperative visual loss (POVL) is a devastating injury that has been reported infrequently after nonocular surgery. The most common cause of POVL is ischemic optic neuropathy (ION). Increasing numbers of cases of ION are being reported after spine surgery, but the etiology of postoperative ION remains poorly understood. After a MEDLINE search of the literature, we reviewed published case reports of ION, specifically those reported after spine surgery performed with the patient in the prone position. Most of the cases involved posterior ION (PION, n = 17), and the remainder anterior (AION, n = 5). Most patients had no or few preoperative vascular disease risk factors. All except one PION and 2 of 5 AION cases reported symptom onset within the first 24 hours after surgery. Visual loss was frequently bilateral (40% of AION, 47% of PION cases). Mean operative time exceeded 450 minutes. The lowest average intraoperative mean arterial blood pressure was 64 mm Hg and the mean lowest intraoperative hematocrit was 27%. The average blood loss was 1.7 L for AION and 5 L for PION patients. PION patients received an average of 8 L of crystalloid solution and 2.2 L of colloid intraoperatively. This compilation of case reports suggests that a combination of prolonged surgery in the prone position, decreased ocular perfusion pressure, blood loss and anemia/hemodilution, and infusion of large quantities of intravenous fluids are some of the potential factors involved in the etiology of postoperative ION. However, levels of blood pressure and anemia intraoperatively were frequently at levels considered acceptable in anesthesia practice. The etiology of postoperative ION remains incompletely understood. Potential strategies to avoid this complication are discussed.
PMCID: PMC2699455  PMID: 15632541
ischemic optic neuropathy; optic nerve; spine surgery; visual loss
7.  Temporary postoperative visual loss associated with intracerebral hemorrhage after laparoscopic appendectomy: a case report 
Korean Journal of Anesthesiology  2014;67(3):221-224.
Postoperative visual loss (POVL) after non-ophthalmic surgery is rare, with a reported incidence ranging from 0.013 to 0.2%. Most perioperative visual loss is associated with spine operations and cardiac bypass procedures. The most common cause of POVL is ischemic optic neuropathy. However, there are no previous reports of postoperative visual loss after laparoscopic appendectomy. A 43-year-old female with no underlying disease underwent laparoscopic appendectomy; the operation was completed in one hour and her blood pressure was stable during the perioperative period. In the post-anesthetic care unit, the patient complained of nausea and headache, but she did not complain of any unusual visual symptoms. Approximately one hour after arriving at the ward, the patient complained of visual disturbance. Neurologic examination revealed left homonymous hemianopsia, and subarachnoid hemorrhage and intracerebral hemorrhage were found in the occipital area on brain MRI.
doi:10.4097/kjae.2014.67.3.221
PMCID: PMC4188771  PMID: 25302101
Complications; Laparoscopic appendectomy; Postoperative visual loss
8.  Amaurosis after spine surgery: survey of the literature and discussion of one case 
European Spine Journal  2010;20(2):171-176.
Postoperative vision loss (POVL) associated with spine surgery is a well known, albeit very rare complication. POVL incidence after spinal surgery ranges from 0.028 to 0.2%; however, due to the increase in number and duration of annual complex spinal operations, the incidence may increase. Origin and pathogenesis of POVL remain frequently unknown. A 73-year-old patient presented with lumbar disc herniation with associated neurological deficits after conservative pre-treatment at a peripheral hospital. Known comorbidities included arterial hypertension, moderate arterial sclerosis, diabetes mellitus type 2, mildly elevated blood lipids and treated prostate gland cancer. During lumbar spine surgery in modified prone position the patient presented with an acute episode of severe hypotension, which required treatment with catecholamines and Trendelenburg positioning. Three hours postoperatively, a visual loss in the right eye occurred, resulting in a complete amaurosis. Antihypertensive medication, arteriosclerosis and intraoperative hypotension are possible causes for the POVL. Intraoperative administration of catecholamines and Trendelenburg positioning for treatment of systemic hypotension might further compromise ocular perfusion. In patients with comorbidities compromising arterial blood pressure, blood circulation and microcirculation, POVL must be considered as a severe postoperative complication. It is recommended to inform patients about such complications and obtain preoperative informed consent regarding POVL. Any recent modification of antihypertensive medication must be reported and analysed for potential intraoperative hemodynamic consequences, prior to spine surgery in prone position.
doi:10.1007/s00586-010-1557-9
PMCID: PMC3030706  PMID: 20809093
Amaurosis; Blood pressure; Spinal surgery; Prone position; Postoperative vision loss (POVL)
9.  Two cases of bilateral ischemic optic neuropathy following coronary artery bypass grafting 
The Australasian Medical Journal  2012;5(7):352-354.
Postoperative vision loss (POVL) after major non-ocular surgery is a very rare but devastating complication since it has the potential to cause bilateral, severe and permanent loss of vision. The common major procedures resulting in POVL are cardiac and spinal procedures. We are reporting two patients who presented with features of bilateral anterior ischaemic optic neuropathy after coronary artery bypass grafting.
doi:10.4066/AMJ.2012.1245
PMCID: PMC3413000  PMID: 22905061
Coronary artery bypass grafting; postoperative visual loss; ischemic optic neuropathy
10.  Postoperative Vision Loss after Spine Surgery: A Single-Institution Case-Control Comparison 
The Ochsner Journal  2014;14(2):179-183.
Background
Postoperative vision loss (POVL) after spine surgery is a rare but devastating outcome. We present the first case-control study from a single institution for POVL with the diagnoses of ischemic optic neuropathy or central vision loss after complex spine surgery.
Methods
POVL cases following spine surgeries between December 1995 and December 2010 at the Cleveland Clinic were identified retrospectively using administrative codes. Each instance of POVL was matched to 5 case-control patients based on age, gender, body mass index, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and hematocrit. Duration of anesthesia, fluid volumes, and hemodynamic measurements were then compared between POVL cases and control cases using Wilcoxon rank sum test.
Results
Six patients developed POVL. These patients had significantly greater blood loss (P=0.002, Wilcoxon test) and a significantly greater volume of red blood cells transfused (P=0.006) than the control patients. No other intraoperative measures differed significantly after Bonferroni correction for multiple outcomes.
Conclusion
We found that patients with POVL had significantly greater blood loss and significantly more red blood cell transfusions than their matched controls.
PMCID: PMC4052583  PMID: 24940126
Optic neuropathy–ischemic; spinal fusion; surgical procedures–operative; vision–ocular
11.  A case report and brief review of the literature on bilateral retinal infarction following cardiopulmonary bypass for coronary artery bypass grafting 
Postoperative visual loss is a devastating perioperative complication. The commonest aetiologies are anterior ischaemic optic neuropathy (AION), posterior ischaemic optic neuropathy (PION), and central retinal artery occlusion (CRAO). These appear to be related to certain types of operation, most commonly spinal and cardiac bypass procedures; with the rest divided between: major trauma causing excessive blood loss; head/neck and nasal or sinus surgery; major vascular procedures (aortic aneurysm repair, aorto-bifemoral bypass); general surgery; urology; gynaecology; liposuction; liver transplantation and duration of surgery. The non-surgical risk factors are multifactorial: advanced age, prolonged postoperative anaemia, positioning (supine v prone), alteration of venous drainage of the retina, hypertension, smoking, atherosclerosis, hyperlipidaemia, diabetes, hypercoagulability, hypotension, blood loss and large volume resuscitation. Other important cardiac causes are septic emboli from bacterial endocarditis and emboli caused by atrial myxomata. The majority of AION cases occur during CPB followed by head/neck surgery and prone spine surgery. CPB is used to allow coronary artery bypass grafting on a motionless heart. It has many side-effects and complications associated with its use and we report here a case of bilateral retinal infarction during routine coronary artery bypass grafting in a young male patient with multiple risk factors for developing this complication despite steps to minimise its occurrence.
doi:10.1186/1749-8090-6-154
PMCID: PMC3253690  PMID: 22104114
12.  Human Erythropoietin Effect in Postoperative Visual Loss Following Spine Surgery: A Case Report 
Introduction:
Postoperative visual loss (POVL) has become the focus of attention for anesthesiologists as a hallmark of perioperative management in spine surgery. A number of Intraoperative and postoperative factors has been documented but the exact etiology is still unclear. Nowadays, perioperative management and also complete curing of POLV is a big question of ophthalmologists and anesthesiologists. The purpose of this case report is to present a unique experience of complete curing the POLV.
Case Presentation:
Our patient was a 61-year-old man, with 75 kg weight and 180 cm height. The patient had no history of visual impairment except mild cataract in his right eye. The patient had a history of diffuse idiopathic skeletal hyperostosis (DISH). The patient had undergone lumbar surgery in prone position. The operation time was about 6 hours. About 30 minutes after transferring to postanesthesia care unit (PACU), patient was awake and complained of losing his eyesight. There was no vision and light perception in his right eye on primary examination. Urgent ophthalmologist consultation was requested. In ophthalmology examinations, the pupil reflex to light was absent in the right eye. After obtaining patients and his family informed consent, four hours after the operation, 40000 I.U. of recombinant human erythropoietin (rhEPO) was administered for patient in PACU (IV infusion, in 30 min). An ophthalmologist visited him every 6 hours after administration of rhEPO. The patient was transferred to intensive care unit (ICU) one hour later with total visual loss in the right eye. Ophthalmologic examination after the second dose of rhEPO, 30 hours after the operation, reported pupil reflex enhancement and light perception in his right eye. Finally the third dose of rhEPO (40000 I.U., IV infusion) was administered on the third day. Ophthalmologic examination after the third dose of rhEPO, 60 hours after the operation, reported normal pupillary light reflex of the right eye and visual acuity improvement to 20/20. The patient was discharged from hospital after six days, with normal visual acuity and without any new complications except surgical site pain.
Conclusions:
Our case report showed the therapeutic effect of rhEPO in complete curing of POVL. Regarding the side effects of EPO such as thrombogenic effects or mild hemodynamic changes like transient sinus tachycardia during infusion, it seems that beneficial effects of EPO is more than its disadvantages and expenses, for patients with POVL.
doi:10.5812/aapm.7291
PMCID: PMC3997951  PMID: 24790903
Complications; Optic Neuropathy, Ischemic; Postoperative Period; Postoperative; Spinal Cord Ischemia; Vision Disorders
13.  Complications associated with prone positioning in elective spinal surgery 
World Journal of Orthopedics  2015;6(3):351-359.
Complications associated with prone surgical positioning during elective spine surgery have the potential to cause serious patient morbidity. Although many of these complications remain uncommon, the range of possible morbidities is wide and includes multiple organ systems. Perioperative visual loss (POVL) is a well described, but uncommon complication that may occur due to ischemia to the optic nerve, retina, or cerebral cortex. Closed-angle glaucoma and amaurosis have been reported as additional etiologies for vision loss following spinal surgery. Peripheral nerve injuries, such as those caused by prolonged traction to the brachial plexus, are more commonly encountered postoperative events. Myocutaneous complications including pressure ulcers and compartment syndrome may also occur after prone positioning, albeit rarely. Other uncommon positioning complications such as tongue swelling resulting in airway compromise, femoral artery ischemia, and avascular necrosis of the femoral head have also been reported. Many of these are well-understood and largely avoidable through thoughtful attention to detail. Other complications, such as POVL, remain incompletely understood and thus more difficult to predict or prevent. Here, the current literature on the complications of prone positioning for spine surgery is reviewed to increase awareness of the spectrum of potential complications and to inform spine surgeons of strategies to minimize the risk of prone patient morbidity.
doi:10.5312/wjo.v6.i3.351
PMCID: PMC4390897  PMID: 25893178
Spine; Patient positioning; Prone position; Complications; Prevention and control
14.  Transient bilateral post-operative visual loss in spinal surgery 
European Spine Journal  2011;21(Suppl 4):495-498.
Background
Post-operative visual loss (POVL) following spinal surgery is a rare but devastating complication. Although a number of intra-operative and post-operative factors have been implicated, the exact etiology may still remain unclear.
Purpose
To report a unique case of transient bilateral POVL in a patient who had undergone lumbar surgery in the prone position.
Study design/setting
This patient was followed up prospectively for 1 year.
Methods
Prospective follow-up of a single patient following spinal surgery, who developed transient bilateral POVL.
Results
This patient’s visual loss improved within 48 h.
Conclusion
This is the only documented case of POVL to have resolved completely within 48 h.
doi:10.1007/s00586-011-2117-7
PMCID: PMC3369061  PMID: 22170448
Post-operative; Visual loss; Spinal surgery
15.  Diabetic retinopathy (treatment) 
BMJ Clinical Evidence  2011;2011:0702.
Introduction
Diabetic retinopathy is the most common cause of blindness in the UK, with older people and those with worse diabetes control, hypertension, and hyperlipidaemia being most at risk. Diabetic retinopathy can cause microaneurysms, haemorrhages, exudates, changes to blood vessels, and retinal thickening.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in people with diabetic retinopathy? What are the effects of treatments for vitreous haemorrhage? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 58 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: peripheral retinal laser photocoagulation, focal and grid laser photocoagulation for maculopathy, corticosteroids for macular oedema, vascular endothelial growth factor inhibitors, and vitrectomy for vitreous haemorrhage.
Key Points
Diabetic retinopathy is the most common cause of blindness in the UK, with older people and those with worse diabetes control, hypertension, and hyperlipidaemia most at risk. Diabetic retinopathy can cause microaneurysms, haemorrhages, exudates, changes to blood vessels, and retinal thickening.
Peripheral retinal laser photocoagulation reduces the risk of severe visual loss compared with no treatment in people with preproliferative (moderate/severe non-proliferative) retinopathy and maculopathy. We don't know if any one type of laser treatment is superior to another.We don't know whether peripheral laser photocoagulation is effective in people with background or preproliferative (non-proliferative) retinopathy without maculopathy because we found no RCTs assessing it in this population.
The benefits of laser photocoagulation are more notable in people with proliferative retinopathy than in those with maculopathy. Focal macular laser photocoagulation reduces the risk of moderate visual loss in eyes with clinically significant macular oedema plus mild to moderate preproliferative (moderate/severe non-proliferative) diabetic retinopathy, compared with no treatment. Grid photocoagulation to zones of retinal thickening may improve visual acuity in eyes with diffuse maculopathy. Photocoagulation is unlikely to be beneficial in eyes with maculopathy but without clinically significant macular oedema.
Intravitreal triamcinolone acetonide improves visual acuity and reduces macular thickness in eyes with macular oedema refractory to previous macular laser photocoagulation, but repeated injections are needed to maintain benefit. Secondary ocular hypertension and progression of cataract are common complications with intravitreal triamcinolone; infectious endophthalmitis is rare.
Intravitreal vascular endothelial growth factor (VEGF) inhibitors pegaptanib and bevacizumab improve visual acuity and reduce macular thickness in eyes with centre-involving diabetic macular oedema and vision loss, but repeat intravitreal injections are needed to maintain benefit. Bevacizumab is not licensed for intraocular use.We don't know the long-term ocular and systemic safety of bevacizumab.We don't know if any one intravitreal VEGF inhibitor or treatment regimen is superior to another.We don't know whether combination treatment with VEGF inhibitor injection plus macular laser photocoagulation is effective as we found only one trial assessing ranibizumab as part of combined treatment.
Vitrectomy can reduce visual loss if performed early in people with vitreous haemorrhage, especially if they have severe proliferative retinopathy. We don't know whether vitrectomy is effective in people with vitreous haemorrhage plus maculopathy as we found no RCTs assessing it.
PMCID: PMC3217806  PMID: 21609511
16.  Ocular vascular occlusive disorders: Natural history of visual outcome☆ 
Ocular vascular occlusive disorders collectively constitute the most common cause of visual disability. Before a disease can be managed, it is essential to understand its natural history, so as to be able to assess the likely effectiveness of any intervention. I investigated natural history of visual outcome in prospective studies of 386 eyes with non-arteritic anterior ischemic optic neuropathy (NA-AION), 16 eyes with non-arteritic posterior ischemic optic neuropathy, 697 eyes with central retinal vein occlusion (CRVO), 67 eyes with hemi-CRVO (HCRVO), 216 eyes with branch retinal vein occlusion (BRVO), 260 eyes with central retinal artery occlusion (CRAO), 151 eyes with branch retinal artery occlusion (BRAO) and 61 eyes with cilioretinal artery occlusion (CLRAO). My studies have shown that every one of these disorders consists of multiple distinct clinical sub-categories with different visual findings. When an ocular vascular occlusive disorder is caused by giant cell arteritis, which is an ophthalmic emergency, it would be unethical to do a natural history study of visual outcome in them, because in this case early diagnosis and immediate, intensive high-dose steroid therapy is essential to prevent any further visual loss, not only in the involved eye but also in the fellow, normal eye.
In NA-AION in eyes seen ≤2 weeks after the onset, visual acuity (VA) improved in 41% of those with VA 20/70 or worse, and visual field (VF) improved in 26% of those with moderate to severe VF defect. In non-ischemic CRVO eyes with VA 20/70 or worse, VA improved in 47% and in ischemic CRVO in 23%; moderate to severe VF defect improved in 79% in non-ischemic CRVO and in 27% in ischemic CRVO. In HCRVO, overall findings demonstrated that initial VA and VF defect and the final visual outcome were different in non-ischemic from ischemic HCRVO – much better in the former than the latter. In major BRVO, in eyes with initial VA of 20/70 or worse, VA improved in 69%, and moderate to severe VF defect improved in 52%. In macular BRVO with 20/70 or worse initial VA, it improved in 53%, and initial minimal-mild VF defect was stable or improved in 85%. In various types of CRAO there are significant differences in both initial and final VA and VF defects. In CRAO eyes seen within 7 days of onset and initial VA of counting fingers or worse, VA improved in 82% with transient non-arteritic CRAO, 67% with non-arteritic CRAO with cilioretinal artery sparing, 22% with non-arteritic CRAO. Central VF improved in 39% of transient non-arteritic CRAO, 25% of non-arteritic CRAO with cilioretinal artery sparing and 21% of non-arteritic CRAO. Peripheral VF improved in non-arteritic CRAO in 39% and in transient non-arteritic CRAO in 39%. In transient CRAO, finally peripheral VFs were normal in 93%. In non-arteritic CRAO eyes initially 22% had normal peripheral VF and in the rest it improved in 39%. Final VA of 20/40 or better was seen in 89% of permanent BRAO, and in 100% of transient BRAO and non-arteritic CLRAO. In permanent BRAO eyes, among those seen within 7 days of onset, central VF defect improved in 47% and peripheral VF in 52%, and in transient BRAO central and peripheral VFs were normal at follow-up.
My studies showed that AION, CRVO, BRVO, CRAO and BRAO, each consist of multiple distinct clinical sub-categories with different visual outcome. Contrary to the prevalent impression, these studies on the natural history of visual outcome have shown that there is a statistically significant spontaneous visual improvement in each category. The factors which influence the visual outcome in various ocular vascular occlusive disorders are discussed.
doi:10.1016/j.preteyeres.2014.04.001
PMCID: PMC4073304  PMID: 24769221
Branch retinal vein occlusion; Central retinal artery occlusion; Central retinal vein occlusion; Non-arteritic anterior ischemic optic neuropathy
17.  Patients' Perspective on Full Disclosure and Informed Consent Regarding Postoperative Visual Loss Associated With Spinal Surgery in the Prone Position 
Mayo Clinic Proceedings  2011;86(9):865-868.
OBJECTIVE: To determine patients' opinions regarding the person, method, and timing for disclosure of postoperative visual loss (POVL) associated with high-risk surgery.
PATIENTS AND METHODS: On the basis of findings of a pilot study involving 219 patients at Mayo Clinic in Florida, we hypothesized that at least 80% of patients would prefer disclosure of POVL by the surgeon, during a face-to-face discussion, before the day of scheduled surgery. To test the hypothesis, we sent a questionnaire to 437 patients who underwent prolonged prone spinal surgical procedures at Mayo Clinic in Rochester, MN, or Mayo Clinic in Arizona from December 1, 2008, to December 31, 2009.
RESULTS: Among the 184 respondents, 158 patients gave responses supporting the hypothesis vs 26 with at least 1 response not supporting it, for an observed incidence of 86%. The 2-sided 95% confidence interval is 80% to 91%.
CONCLUSION: At least 80% of patients prefer full disclosure of the risk of POVL, by the surgeon, during a face-to-face discussion before the day of scheduled surgery. This finding supports development of a national patient-driven guideline for disclosing the risk of POVL before prone spinal surgery.
doi:10.4065/mcp.2011.0279
PMCID: PMC3258003  PMID: 21878598
18.  The trilateral link between anaesthesia, perioperative visual loss and Flammer syndrome 
BMC Anesthesiology  2016;16:10.
Background
A variety of factors have been linked to perioperative visual loss during or directly after nonocular and ocular surgeries. Prolonged immobilization, biochemical factors and hemodynamic instability have been discussed as factors in the pathogenesis of this devastating complication. Perioperative visual loss in four consecutive patients, all featuring Flammer syndrome, is reported herein. To our knowledge, we present the first case series, which associates perioperative visual loss with Flammer syndrome. We assume that a low perfusion pressure, disturbed autoregulation of the ocular blood flow and altered drug sensitivity in such subjects, play significant role in the pathogenesis of this dreaded complication.
Cases presentation
We analysed the medical records of four consecutive patients with permanent perioperative visual loss and complemented our findings with additional history taking and clinical examinations. A variety of tests was performed, including colour Doppler ultrasonography of the retroocular vessels, static and dynamic retinal vessel analysis. The visual loss was unilateral in three patients and bilateral in one. An extensive review of published perioperative vision loss cases was conducted.
All four patients were male Caucasians, and exhibited prominent signs and symptoms of Flammer syndrome. The visual loss originated from a propensity for unstable ocular blood flow, combined with hyperreactivity toward pharmacological stimuli, leading together to disturbed autoregulation of the blood supply, and subsequently - to ocular hypoxia. An identified intrinsic hypoperfusion diathesis was a crucial pathophysiologic link in all of the patients. Other, yet unknown systemic or local factors may also be involved in this process.
Conclusions
A review of numerous publications of perioperative visual loss and our data, support our hypothesis for a novel pathophysiologic model and incorporate Flammer syndrome as a distinct risk factor for paradoxical visual loss, during nonocular and ocular surgeries, or invasive procedures. To prevent the complications produced by disturbed blood flow autoregulation in such patients, guidelines for screening and tailored preoperative approach are given.
doi:10.1186/s12871-016-0176-3
PMCID: PMC4741007  PMID: 26846332
Perioperative visual loss; Flammer syndrome; Autoregulation; Ocular blood flow; Anesthesia; Ocular/nonocular surgery; Doppler ultrasonography; Velocity; Resistance index; Plasma Endothelin-1 level
19.  Glaucoma 
BMJ Clinical Evidence  2009;2009:0703.
Introduction
Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure, but 40% of people with glaucoma have normal intraocular pressure and only 10% of people with raised intraocular pressure are at risk of optic-nerve damage. Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people than in white populations.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for established primary open-angle glaucoma, ocular hypertension, or both? What are the effects of lowering intraocular pressure in people with normal-tension glaucoma? What are the effects of treatment for acute angle-closure glaucoma? We searched: Medline, Embase, The Cochrane Library, and other important databases up to November 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 20 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: laser trabeculoplasty (alone or plus topical medical treatment); topical medical treatments; and surgical trabeculectomy.
Key Points
Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure (IOP), but up to 40% of people with glaucoma have normal IOP and only about 10% of people with raised IOP are at risk of optic-nerve damage.Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people (especially those of West African descent) than in white populations.Blindness from glaucoma results from gross loss of visual field or loss of central vision and, when the optic nerve is vulnerable, can progress quickly without treatment.
Lowering IOP by laser trabeculoplasty plus topical medical treatment may be more effective at reducing progression of glaucoma in people with primary open-angle or pseudoexfoliation glaucoma, compared with no treatment.
Topical medical treatment may reduce the risk of developing glaucoma in people with ocular hypertension compared with placebo.
We don't know whether topical medical treatment, laser trabeculoplasty, orsurgical trabeculectomyare more effective at maintaining visual fields and acuity in primary open-angle glaucoma. Surgery may increase the risk of developing cataracts.
We don't know whether reducing IOP with medical treatment alone or in combination with other treatments including surgery is more effective than no treatment at reducing progression of visual field loss in people with normal-tension glaucoma.
There is a consensus that medical and surgical treatments are beneficial in people with acute angle-closure glaucoma, although we don't know this for sure because it is unethical to withhold pressure-lowering treatment.
PMCID: PMC2907771
20.  Glaucoma 
BMJ Clinical Evidence  2011;2011:0703.
Introduction
Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure, but 40% of people with glaucoma have normal intraocular pressure and only 10% of people with raised intraocular pressure are at risk of optic-nerve damage. Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people than in white populations.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for established primary open-angle glaucoma, ocular hypertension, or both? What are the effects of lowering intraocular pressure in people with normal-tension glaucoma? What are the effects of treatment for acute angle-closure glaucoma? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 12 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: laser trabeculoplasty (alone or plus topical medical treatment), topical medical treatments, and surgical trabeculectomy.
Key Points
Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure (IOP), but up to 40% of people with glaucoma have normal IOP and only about 10% of people with raised IOP are at risk of optic-nerve damage.Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people (especially those of West African descent) than in white populations.Blindness from glaucoma results from gross loss of visual field or loss of central vision and, when the optic nerve is vulnerable, can progress quickly without treatment.
Lowering IOP by laser trabeculoplasty plus topical medical treatment may be more effective at reducing progression of glaucoma in people with primary open-angle or pseudoexfoliation glaucoma, compared with no treatment.
Topical medical treatment may reduce the risk of developing glaucoma in people with ocular hypertension, compared with placebo.
We don't know whether topical medical treatment, laser trabeculoplasty, or surgical trabeculectomy is more effective at maintaining visual fields and acuity in primary open-angle glaucoma. Surgery may increase the risk of developing cataracts.
We don't know whether reducing IOP with medical treatment alone or in combination with other treatments including surgery is more effective than no treatment at reducing progression of visual field loss in people with normal-tension glaucoma.
There is a consensus that medical and surgical treatments are beneficial in people with acute angle-closure glaucoma, although we don't know this for sure because it is unethical to withhold pressure-lowering treatment.
The consensus about how laser treatments compare with medical or surgical treatments in people with acute angle-closure glaucoma is currently uncertain, and more high-quality evidence is needed.
PMCID: PMC3275300  PMID: 21658300
21.  Cataract 
BMJ Clinical Evidence  2011;2011:0708.
Introduction
Cataract accounts for over 47% of blindness worldwide, causing blindness in about 17.3 million people in 1990. Surgery for cataract in people with glaucoma may affect glaucoma control.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of surgery for age-related cataract without other ocular comorbidity? What are the effects of treatment for age-related cataract in people with glaucoma? What are the effects of surgical treatments for age-related cataract in people with diabetic retinopathy? What are the effects of surgical treatments for age-related cataract in people with chronic uveitis? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 20 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: for people with cataract without other ocular co-morbidity: cataract surgery alone, cataract surgery with non-concomitant glaucoma surgery, concomitant cataract and glaucoma surgery, intracapsular extraction, manual (large or small) incision extracapsular extraction, and phaco extracapsular extraction; for people with cataract with co-morbid diabetic retinopathy: cataract surgery alone, and adding diabetic retinopathy treatment to cataract surgery; for people with cataract and co-morbid chronic uveitis: cataract surgery, and medical control of uveitis at the time of cataract surgery.
Key Points
Cataracts are cloudy or opaque areas in the lens of the eye that can impair vision. Age-related cataracts are defined as those occurring in people >50 years of age, in the absence of known mechanical, chemical, or radiation trauma. Cataract accounts for over 47% of blindness worldwide, causing blindness in about 17.3 million people in 1990.Surgery for cataract in people with glaucoma may affect glaucoma control.There is contradictory evidence about the effect of cataract surgery on the development or progression of age-related macular degeneration (ARMD).
Expedited phaco extracapsular extraction may be more effective at improving visual acuity compared with waiting list control in people with cataract without ocular comorbidities. When combined with foldable posterior chamber intraocular lens implant (IOL), phaco extracapsular extraction seems more effective than manual large-incision extracapsular extraction at improving vision, and has fewer complications.This procedure has largely superseded manual large-incision extracapsular cataract extraction in developed countries.
Manual large-incision extracapsular extraction has also been shown to be successful in treating cataracts. Combined with IOL, manual large-incision extracapsular extraction is significantly better at improving vision compared with intracapsular extraction plus aphakic glasses.Small-incision manual extracapsular extraction (manual SICS) techniques and phaco extracapsular extraction techniques are similarly beneficial at improving visual acuity for advanced cataracts at 6 months, with few complications.This finding may be particularly relevant to treatment in developing countries.
Intracapsular extraction is likely to be better at improving vision compared with no extraction, although it is not as beneficial as manual (large or small) incision extracapsular extraction. The rate of complications is also higher with this technique compared with extracapsular extraction.
In people with glaucoma and cataract, concomitant cataract surgery (phaco or manual large-incision extracapsular extraction) and glaucoma surgery seems more beneficial than cataract surgery alone, in that they both improve vision to a similar extent, but the glaucoma surgery additionally improves intraocular pressure. We found no trials comparing different types of cataract surgery in people with glaucoma.
In people with diabetic retinopathy and cataract, phaco extracapsular extraction may improve visual acuity and reduce postoperative inflammation compared with manual large-incision extraction. Performing procedures in the order of cataract surgery first followed by pan retinal photocoagulation may be more effective than the opposite order at improving visual acuity and reducing the progression of diabetic macular oedema in people with cataract and diabetic retinopathy secondary to type 2 diabetes. However, these results come from one small RCT.
One of the possible harms of cataract surgery is cystoid macular oedema, which people with uveitis also frequently suffer from. We found no trials comparing different types of cataract surgery in people with chronic uveitis.We don't know whether intravitreal triamcinolone acetonide is more effective than orbital floor injection of triamcinolone acetonide in improving outcomes after cataract surgery in people with chronic uveitis as we found few trials.
PMCID: PMC3275311  PMID: 21718561
22.  Optical Coherence Tomography for Age-Related Macular Degeneration and Diabetic Macular Edema 
Executive Summary
Objective
The purpose of this evidence-based review was to examine the effectiveness and cost-effectiveness of spectral-domain (SD) optical coherence tomography (OCT) in the diagnosis and monitoring of patients with retinal disease, specifically age-related macular degeneration (AMD) and diabetic macular edema (DME). Specifically, the research question addressed was:
What is the sensitivity and specificity of spectral domain OCT relative to the gold standard?
Clinical Need: Target Population and Condition
The incidence of blindness has been increasing worldwide. In Canada, vision loss in those 65 years of age and older is primarily due to AMD, while loss of vision in those 18 years of age and older is mainly due to DME. Both of these conditions are diseases of the retina, which is located at the back of the eye. At the center of the retina is the macula, a 5 mm region that is responsible for what we see in front of us, our ability to detect colour, and fine detail. Damage to the macula gives rise to vision loss, but early detection of asymptomatic disease may lead to the prevention or slowing of the vision loss process.
There are two main types of AMD, ‘dry’ and ‘wet’. Dry AMD is the more prevalent of the two, accounting for approximately 85% of cases and characterized by small deposits of extracellular material called “drusen” that build up in Bruch’s membrane of the eye. Central vision loss is gradual with blurring and eventual colour fading. Wet AMD is a less prevalent condition (15% of all AMD cases) but it accounts for 90% of severe cases. It’s characterized by the appearance of retinal fluid with vision loss due to abnormal blood vessels/leakage within weeks to months of diagnosis. In 2003, the Canadian National Institute for the Blind (CNIB) prevalence estimate for AMD was 1 million Canadians, including approximately 400,000 affected Ontarians. The incidence in 2003 was estimated to be 78,000 new cases in Canada, with approximately one-third of these cases arising in Ontario (n=26,000). Over the next 25 years, the number of new cases is expected to triple.
DME is caused by complications of diabetes mellitus, both Type 1 and Type 2. It is estimated that 1-in-4 persons with diabetes has this condition, though it occurs more frequently among those with type 2 diabetes. The condition is characterized by a swelling of the retina caused by leakage of blood vessels at the back of the eye. In early stages of the disease, vision may still be normal but it can degrade rapidly in later stages. In 2003, the CNIB prevalence estimate for DME was 0.5 million Canadians, with approximately 200,000 Ontarians affected. The incidence of DME is more difficult to ascertain; however, based on an annual incidence rate of 0.8% (for those 20 years of age or older) and the assumption that 1-in-4 persons with diabetes is affected, the incidence of DME in Ontario is estimated to be 21,000 new cases per year.
Optical Coherence Tomography
Prior to the availability of OCT, the standard of care in the diagnosis and/or monitoring of retinal disease was serial testing with fluorescein angiography (FA), biomicroscopy (BM), and stereo-fundus photography (SFP). Each of these is a qualitative measure of disease based on subjective evaluations that are largely dependent on physician expertise. OCT is the first quantitative visual test available for the diagnosis of eye disease. As such, it is allows for a more objective evaluation of the presence/absence of retinal disease and it is the only test that provides a measure of retinal thickness. The technology was developed at the Michigan Institute of Technology (MIT) in 1991 as a real-time imaging modality and is considered comparable to histology. It’s a light-wave based technology producing cross-sectional images with scan rates and resolution parameters that have greatly improved over the last 10 years. It’s also a non-invasive, non-contact visual test that requires just 3 to 5 minutes to assess both eyes.
There are two main types of OCT system, both licensed by Health Canada as class II devices. The original patent was based on a time domain (TD) system (available from 1995) that had an image rate of 100 to 400 scans per second and provided information for a limited view of the retina with a resolution in the range of 10 to 20 μm. The newer system, spectral domain (SD) OCT, has been available since 2006. Improvements with this system include (i) a faster scan speed of approximately 27,000 scans per second; (ii) the ability to scan larger areas of the retina by taking six scans radially-oriented 30 degrees from each other; (iii) increased resolution at 5μm; and (iv) ‘real-time registration,’ which was not previously available with TD.
The increased scan speed of SD systems enables the collection of additional real-time information on larger regions of the retina, thus, reducing the reliance on assumptions required for retinal thickness and volume estimates based on software algorithms. The faster scan speed also eliminates image distortion arising from patient movement (not previously possible with TD), while the improvement in resolution allows for clearer and more distinguishable retinal layers with the possibility of detecting earlier signs of disease. Real-time registration is a new feature of SD that enables the identification of specific anatomical locations on the retina, against which subsequent tests can be evaluated. This is of particular importance in the monitoring of patients. In the evaluation of treatment effects, for example, this enables the same anatomic retinal location to be identified at each visit.
Methods
Literature Search
A literature search was performed on February 13, 2009 using Ovid MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for studies published from January 2003 to February 2009. The subject headings and keywords searched included AMD, DME, and OCT (the detailed search strategy can be viewed in Appendix 1). Excluded were case reports, comments, editorials, non-systematic reviews, and letters. Abstacts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. In total, 542 articles were included for review.
English-language articles and health technology assessments.
RCTs and observational studies of OCT and AMD or DME.
Studies focusing on either diagnosis or monitoring of disease.
Studies in which outcomes were not specific to those of interest in this report.
Studies of pediatric populations.
Studies on OCT as a screening tool.
Studies that did not assess comparative effectiveness of OCT with a referent, as specified below in “Comparisons of Interest”.
Outcomes of Interest
Studies of sensitivity, specificity.
Comparisons of Interest
Evidence exists for the following comparisons of interest:
OCT compared with the reference “fluorescein angiography” for AMD.
OCT compared with the reference “biomicroscopy” or “stereo or fundus photography” for DME.
Summary of Existing Evidence
No evidence for the accuracy of SD OCT compared to either FA, BM or SFP was published between January 2006 to February 2009; however, two technology assessments were found, one from Alberta and the other from Germany, both of which contain evidence for TD OCT. Although these HTAs included eight studies each, only one study from each report was specific to this review. Additionally, one systematic review was identified for OCT and DME. It is these three articles, all pertaining to time and not spectral domain OCT, as well as comments from experts in the field of OCT and retinal disease, that comprise the evidence contained in this review.
Upon further assessment and consultations with experts in the methodology of clinical test evaluation, it was concluded that these comparators could not be used as references in the evaluation of OCT. The main conclusion was that, without a third test as an arbiter, it is not possible to directly compare the sensitivity and specificity of OCT relative to either FA for AMD and stereo- or fundus – photography for DME. Therefore, in the absence of published evidence, it was deemed appropriate to consult a panel of experts for their views and opinions on the validity of OCT and its utility in clinical settings. This panel consisted of four clinicians with expertise in AMD and/or DME and OCT, as well as a medical biophysicist with scientific expertise in ocular technologies. This is considered level 5 evidence, but in the absence of an appropriate comparator for further evaluation of OCT, this may be the highest level of evidence possible.
Summary of Findings
The conclusions for SD OCT based on Level 5 evidence, or expert consultation, are as follows:
OCT is considered an essential part of the diagnosis and follow-up of patients with DME and AMD.
OCT is adjunctive to FA for both AMD and DME but should decrease utilization of FA as a monitoring modality.
OCT will result in a decline in the use of BM in the monitoring of patients with DME, given its increased accuracy and consistency.
OCT is diffusing rapidly and the technology is changing. Since FA is still considered pivotal in the diagnosis and treatment of AMD and DME, and there is no common outcome against which to compare these technologies, it is unlikely that RCT evidence of efficacy for OCT will ever be forthcoming.
In addition to the accuracy of OCT in the detection of disease, assessment of the clinical utility of this technology included a rapid review of treatment effects for AMD and DME. The treatment of choice for AMD is Lucentis®, with or without Avastin® and photodynamic therapy. For DME the treatment of choice is laser photocoagulation, which may be replaced with Lucentis® injections (Expert consultation). The evidence, as presented in systematic reviews and other health technology assessments, indicates that there are effective treatments available for both AMD and DME.
Considerations for the Ontario Health System
OCT testing is presently an uninsured service in Ontario with patients paying approximately $150 out-of-pocket per test. Several provinces do provide funding for this procedure, including British Columbia, Alberta, Saskatchewan, Newfoundland, Nova Scotia, Prince Edward Island, and the Yukon Territory. Provinces that do not provide such funding are Quebec, Manitoba and New Brunswick.
The demand for OCT is expected to increase with aging of the population.
PMCID: PMC3377511  PMID: 23074517
23.  Perioperative vision loss: A complication to watch out 
Postoperative vision loss, a rare but devastating complication, has been reported after spine, cardiac, and head–neck surgeries. Its incidence following spine surgeries exceeds that after cardiothoracic surgeries. Various causes attributed to postoperative blindness include ischemic optic neuropathy, central or branch retinal artery occlusion, cortical blindness, and rarely external ocular injury. Other contributory factors described are microvascular diseases and intraoperative hemodynamic compromise. However, the exact association of these factors with postoperative blindness has not yet been confirmed. In this review, we describe causes, presentation, and treatment of postoperative blindness and also recommend practical guidelines to avoid this complication. The search strategies for this review included both search of electronic databases as well as manual search of relevant articles.
doi:10.4103/0970-9185.92427
PMCID: PMC3275941  PMID: 22345938
Postoperative blindness; spine surgery; vision loss
24.  Anterior ischemic optic neuropathy after conventional coronary artery bypass graft surgery 
Summary
Background
Perioperative optic neuropathy is a disease which can lead to serious, irreversible damage of vision. This complication could be the result of non-ocular surgery, for example, cardiac or spinal procedures.
We present a case of anterior ischemic neuropathy (AION) which occurred following a conventional coronary artery bypass graft procedure.
Case Report
A 57-year-old man, 4 days after Conventional Coronary Artery Bypass Graft surgery as result of multi-vessel stabile coronary artery disease and history of anterolateral wall myocardial infarction, was admitted to the Eye Clinic due to significant loss of vision in his right eye. The patient had hypertension and was a heavy smoker. On admission, the slit lamp examination revealed a relative afferent pupillary defect in the right eye. The fundus examination showed optic disc edema with the presence of flame hemorrhages. Best corrected visual acuity (BCVA) was 0.02. The results of eye examination and fluorescein angiography confirmed the diagnosis of AION. Anti-aggregation and antithrombotic treatment was continued with steroids and vasodilators. After 7 days of this treatment we noticed the improvement of BCVA to 0.2. At 6-month follow-up, the vision was stable, and fundus examination revealed optic disc atrophy.
Conclusions
After cardiac surgical operations, such as coronary artery bypass graft procedures, anterior ischemic optic neuropathy may occur. In those cases, close cooperation between the various specialists is necessary.
doi:10.12659/MSM.881798
PMCID: PMC3539541  PMID: 21629193
coronary artery bypass graft; off-pump coronary artery bypass; perioperative ischemic neuropathy; anterior ischemic optic neuropathy
25.  Diabetic retinopathy 
BMJ Clinical Evidence  2007;2007:0702.
Introduction
Diabetic retinopathy is the most common cause of blindness in the UK, with older people and those with worse diabetic control, hypertension, and hyperlipidaemia being most at risk. Diabetic retinopathy can cause microaneurysms, haemorrhages, exudates, changes to blood vessels, and retinal thickening.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in people with diabetic retinopathy? What are the effects of treatments for vitreous haemorrhage? We searched: Medline, Embase, The Cochrane Library and other important databases up to November March 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 29 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: peripheral retinal laser photocoagulation, focal and grid laser photocoagulation for maculopathy, corticosteroids for macular oedema, and vitrectomy for vitreous haemorrhage.
Key Points
Diabetic retinopathy is the most common cause of blindness in the UK, with older people and those with worse diabetic control, hypertension, and hyperlipidaemia most at risk. Diabetic retinopathy can cause microaneurysms, haemorrhages, exudates, changes to blood vessels, and retinal thickening.
Peripheral retinal laser photocoagulation reduces the risk of severe visual loss compared with no treatment in people with preproliferative (moderate/severe non-proliferative) retinopathy and maculopathy. We don't know if any one type of laser treatment is superior.We don't know whether peripheral laser photocoagulation is beneficial in people with background or preproliferative (non-proliferative) retinopathy without maculopathy.
The benefits of laser photocoagulation are more notable in people with proliferate retinopathy than in those with maculopathy. Focal macular laser photocoagulation reduces the risk of moderate visual loss in eyes with clinically significant macular oedema plus mild to moderate preproliferative (moderate/severe non-proliferative) diabetic retinopathy, compared with no treatment. Grid photocoagulation to zones of retinal thickening may improve visual acuity in eyes with diffuse maculopathy. Photocoagulation is unlikely to be beneficial in eyes with maculopathy but without clinically significant macular oedema.
Intravitreal triamcinolone acetonide improves visual acuity and reduces macular thickness in eyes with macular oedema refractory to previous macular laser photocoagulation, but repeated injections are needed to maintain benefit. Secondary ocular hypertension and progression of cataract are common complications with intravitreal triamcinolone; infectious endophthalmitis is rare.
Vitrectomy can reduce visual loss if performed early in people with vitreous haemorrhage, especially if they have severe proliferative retinopathy. We don't know whether vitrectomy is beneficial in people with vitreous haemorrhage plus maculopathy.
PMCID: PMC2943811  PMID: 19450351

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