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1.  Comparison of Spectral-Domain and Time-Domain Optical Coherence Tomography in Solar Retinopathy 
The purpose of this article is to compare spectral-domain (SD) and time-domain (TD) optical coherence tomography (OCT) findings in patients with solar retinopathy. Complete ocular examinations and OCT were performed in two patients presenting with acute solar retinopathy soon after observation of an eclipse. Both patients were evaluated with SD-OCT and TD-OCT at the same time. SD-OCT demonstrated characteristic defects at the level of the inner and outer segment junction of the photoreceptors in all the affected eyes and decreased reflectiveness of the retinal pigment epithelium layer. TD-OCT images showed unremarkable findings in two eyes with deteriorated visual acuity. SD-OCT improves diagnosis and assessment of the degree and nature of foveal damage in patients with solar retinopathy and may be an important tool for use in identifying foveal damage not detected by TD-OCT. SD-OCT may be preferable to TD-OCT for confirmation or assessment of the degree of foveal damage in patients with solar retinopathy.
doi:10.3341/kjo.2011.25.4.278
PMCID: PMC3149141  PMID: 21860577
Optical coherence tomography; Retinal disease; Solar energy
2.  High-Speed Ultrahigh-Resolution Optical Coherence Tomography Findings in Chronic Solar Retinopathy 
Retinal cases & brief reports  2008;2(2):103-105.
Purpose
To describe ocular findings for a 34-year-old man with chronic solar retinopathy using high-speed ultrahigh-resolution (UHR) optical coherence tomography (OCT).
Methods
Fundus photography, fluorescein angiography, and Stratus OCT (Carl Zeiss Meditec, Inc., Dublin, CA) were performed. A high-speed UHR OCT prototype developed in our ophthalmology clinic was used to obtain detailed images of the retina.
Patients
Two eyes of one patient with chronic solar retinopathy were studied.
Results
Both Stratus OCT and high-speed UHR OCT demonstrated foveal thinning bilaterally. In addition, high-speed UHR OCT showed distinct hyporeflective disruptions in the photoreceptor inner segment/outer segment junction and photoreceptor outer segments bilaterally. En face OCT images from three-dimensional OCT data sets revealed hyporeflective regions of photoreceptor atrophy in the outer retina.
Conclusions
High-speed UHR OCT showed more detail than standard OCT, and findings were consistent with histopathologic and ultrastructural features that have been reported previously. Solar retinopathy should be studied further with high-speed UHR OCT to determine the short- and long-term effects of solar radiation damage.
doi:10.1097/ICB.0b013e3181506993
PMCID: PMC2743270  PMID: 19756263
optical coherence tomography; solar retinopathy; ultrahigh-resolution optical coherence tomography
3.  Optical Coherence Tomography Findings in Autoimmune Retinopathy 
American journal of ophthalmology  2012;153(4):750-756.e1.
PURPOSE
To report optical coherence tomography (OCT) features of patients with autoimmune retinopathy.
DESIGN
Consecutive case series.
METHOD
Eight patients who presented with unexplained loss of central vision, visual field defects, and/or photopsia were diagnosed with autoimmune retinopathy based on clinical features, electroretinogram (ERG) findings, and serum antiretinal antibody analysis. All patients underwent OCT testing of the macula and nerve fiber layer (NFL).
RESULTS
Outer retinal abnormalities and/or decreased macular thickness on OCT were seen in all patients. Macular OCT showed reduced central macular and foveal thicknesses in 6 patients (mean thickness 143 ± 30 μm and 131 ± 29 μm respectively). In all but 1 patient, loss of the photoreceptor layer or disruption of the photoreceptor outer and inner segment junction was noted. Three patients showed only mild to moderate focal NFL loss.
CONCLUSIONS
Retinal atrophy and reduced macular thickness on OCT are predominant features in patients with autoimmune retinopathy. OCT provides objective measures of retinal damage and may offer clues toward understanding the mechanism of visual dysfunction and the diagnosis of autoimmune retinopathy.
doi:10.1016/j.ajo.2011.09.012
PMCID: PMC3495560  PMID: 22245461
4.  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
5.  A Comparison of Visual Field Sensitivity to Photoreceptor Thickness in Retinitis Pigmentosa 
Fd-OCT provides in vivo assessment of retinal structure in retinitis pigmentosa. The relationships between outer nuclear thickness, photoreceptor outer segment thickness, and visual field sensitivity were examined in this study.
Purpose.
To explore the relationship between visual field sensitivity and photoreceptor layer thickness in patients with retinitis pigmentosa (RP).
Methods.
Static automated perimetry (central 30-2 threshold program with spot size III; Humphrey Field Analyzer; Carl Zeiss Meditec, Inc., Dublin, CA) and frequency domain optical coherence tomography (Fd-OCT) scans (Spectralis HRA+OCT; Heidelberg Engineering, Vista, CA) were obtained from 10 age-matched normal control subjects and 20 patients with RP who had retained good central vision (better than 20/32). The outer segment (OS+) thickness (the distance between retinal pigment epithelium [RPE])/Bruch's membrane [BM] to the photoreceptor inner–outer segment junction), outer nuclear layer (ONL), and total retinal thickness were measured at locations corresponding to visual field test loci up to 21° eccentricity.
Results.
The average OS+ thickness in the control eyes was 63.1 ± 5.2 μm, varying from approximately 69 μm in the foveal center to 56 μm at 21° eccentricity. In patients with RP, OS+ thickness was below normal limits outside the fovea, and thickness decreased with loss in local field sensitivity, reaching an asymptotic value of 21.5 μm at approximately −10 dB. The ONL thickness also decreased with local field sensitivity loss. Although relative OS thickness was linearly related to visual field loss at all locations examined, a slightly better correlation was found between the product of OS and ONL thickness and visual field loss.
Conclusions.
In patients with RP with good foveal sensitivity, the OS thickness and the product of OS thickness and ONL thickness (assumed to represent the number of photoreceptors) decreases linearly with loss of local field sensitivity. In general, in regions where perimetric sensitivity loss is −10 dB or worse, the OS+ thickness approaches the thickness of the RPE/BM complex.
doi:10.1167/iovs.09-4945
PMCID: PMC2910646  PMID: 20220048
6.  Combined Depth Imaging technique on spectral-domain optical coherence tomography 
American journal of ophthalmology  2012;155(4):727-732.e1.
PURPOSE
To describe a technique to obtain combined images of vitreo-retino-choroidal structures using spectral-domain (SD) optical coherence tomography (OCT) and to evaluate applicability in normal eyes and limitations in eyes with cataract.
DESIGN
Prospective, observational case series.
METHODS
Three different foveal scans including conventional SD-OCT, enhanced depth imaging (EDI)-OCT and the novel method called “combined depth imaging” (CDI)-OCT were obtained in 42 eyes of healthy volunteers and in 26 eyes with cataract using Heidelberg Spectralis HRA. The CDI-OCT was manually obtained using an image modification process that enhances the vitreo-retinal interface first and then the choroid while averaging 100 separate OCT scans. The visualization of the inner border of the preretinal pocket and the outer border of the choroid was graded by independent masked observers for each OCT scan modality.
RESULTS
The CDI technique was able to create a good quality combined image of the posterior structures in all the eyes including eyes with cataract. The agreement between the grading performed by the independent observers was high for both the inner border of the vitreal pocket (kappa=0.86; P<0.001) and the outer choroidal border (kappa=0.90; P<0.001). CDI-OCT was equivalent to conventional SD-OCT in visualizing the vitreal pocket (P=0.445 for normal eyes, P=0.162 for eyes with cataract) and was equivalent to EDI-OCT in visualizing the outer choroidal border (P=0.660 for normal eyes, P=0.329 for eyes with cataract). CDI-OCT was superior to conventional SD-OCT and EDI-OCT to visualize both the structures (P<0.001).
CONCLUSIONS
The manual technique of CDI-OCT is highly sensitive to visualize posterior vitreo-retino-choroidal structures into a single full-depth image, and is not affected by mild to moderate cataract.
doi:10.1016/j.ajo.2012.10.019
PMCID: PMC3608846  PMID: 23253912
7.  Spectral domain optical coherence tomography as an effective screening test for hydroxychloroquine retinopathy (the “flying saucer” sign) 
Purpose
While the long-term incidence of hydroxychloroquine (HCQ) retinopathy is low, there remains no definitive clinical screening test to recognize HCQ toxicity before ophthalmoscopic fundus changes or visual symptoms. Patients receiving HCQ were evaluated with spectral domain optical coherence tomography (SD OCT) to assess the feasibility of identifying HCQ retinopathy at an early stage.
Methods
Twenty-five patients referred for the evaluation of hydroxychloroquine toxicity underwent a comprehensive ocular examination, Humphrey visual field (HVF) perimetry, time domain OCT, and SD OCT. Some patients with screening abnormalities also underwent further diagnostic testing at the discretion of the treating providers.
Results
Five patients were found to have SD OCT findings corresponding to HCQ toxicity and retinal damage as seen by clinical exam and/or HVF perimetry. Two patients with advanced toxicity were found to have significant outer retina disruption in the macula on SD OCT. Three patients with early HCQ toxicity and HVF 10-2 perifoveal defects were found to have loss of the perifoveal photoreceptor inner segment/outer segment (IS/OS) junction with intact outer retina directly under the fovea, creating the “flying saucer” sign. While two of these three patients had early ophthalmoscopic fundus changes, one had none.
Conclusion
Outer retinal abnormalities including perifoveal photoreceptor IS/OS junction disruption can be identified by SD OCT in early HCQ toxicity, sometimes even before ophthalmoscopic fundus changes are apparent. SD OCT may have a potential complementary role in screening for HCQ retinopathy due to its quick acquisition and because it is more objective than automated perimetry.
doi:10.2147/OPTH.S14257
PMCID: PMC2964950  PMID: 21060664
drug toxicity; hydroxychloroquine; photoreceptors; screening test; spectral domain optical coherence tomography
8.  Uveitic Foveal Atrophy: Clinical Features and Associations 
Archives of ophthalmology  2009;127(2):179-186.
Objective
To characterize foveal atrophy in a heterogeneous group of uveitis patients using clinical findings and high-definition optical coherence tomography (HD-OCT).
Design
Cross-sectional, retrospective case series.
Results
HD-OCT scans of 140 patients seen in a tertiary referral center were reviewed and 23 patients (33 eyes) with foveal atrophy were identified. All patients with foveal atrophy were diagnosed with intermediate uveitis, posterior uveitis, or panuveitis. The status of the photoreceptor layer as visualized with HD-OCT was associated with significant differences in mean visual acuity (p<0.0001). Clinical findings associated with foveal atrophy included atrophy of the retinal pigment epithelium (RPE) and/or choroid (91%), macular ischemia (39%), cystoid macular edema (15%), choroidal neovascularization (12%), retinal detachment involving the macula (6%), and serum antiretinal antibodies (6%).
Conclusions
Foveal atrophy can be a complication of intraocular inflammation in a variety of uveitic syndromes. The etiology of foveal atrophy is multi-factorial and may include dysfunction and atrophy of the RPE and/or choroid, cystoid macular edema, macular ischemia secondary to occlusive retinal vasculitis, choroidal neovascularization, retinal detachment, and possibly antibody-mediated damage directed against photoreceptors. Careful observation of the photoreceptor layer using HD-OCT may help to identify patients who are at risk for visual loss secondary to foveal atrophy.
doi:10.1001/archophthalmol.2008.564
PMCID: PMC2653214  PMID: 19204236
9.  High-resolution spectral domain optical coherence tomography and fundus autofluorescence correlation in tubercular serpiginouslike choroiditis 
Objective
This study aims to describe changes in high-resolution spectral domain optical coherence tomography (SD-OCT) scans with simultaneous fundus autoflorescence (FAF) signals in tubercular serpiginouslike choroiditis (SLC).
Methods
Simultaneous SD-OCT and FAF imaging of eyes affected with SLC from acute stage until resolution of lesions was obtained using Spectralis HRA+OCT system (Heidelberg Engineering, Heidelberg, Germany).
Patients
Four eyes (three patients) with SLC were prospectively followed.
Results
Acute lesions of SLC (diffusely hyperautofluorescent) corresponded to hyperreflective areas on SD-OCT involving the retinal pigment epithelium (RPE), photoreceptor outer segment tips (POST), inner segment–outer segment (IS/OS) junction, external limiting membrane (ELM), and outer nuclear layer (ONL) with a minimal distortion of inner retinal layers. There was no backscattering from inner choroid. During healing, lesions became discrete with a hypoautofluorescent border and predominant hyperautofluorescence centrally. The hyperreflective fuzzy areas on SD-OCT scans disappeared, and irregular, knobbly elevations of outer retinal layers appeared. The RPE, POST, IS/OS junction, and ELM could not be distinguished. The ONL appeared normal. The choroid showed an increased reflectance. As the lesions healed further over the next 3–6 months, they became predominantly hypoautofluorescent with loss of RPE, POST, IS/OS junction, and ELM in SD-OCT scan.
Conclusion
The SD-OCT provided an insight into the ultrastructural changes in the outer retina during the course of acute SLC lesions. The changes on OCT correlated with abnormal FAF findings.
doi:10.1007/s12348-011-0037-7
PMCID: PMC3223337  PMID: 21847595
Fundus autofluorescence; Spectral domain optical coherence tomography; Tubercular serpiginouslike choroiditis
10.  High-resolution spectral domain optical coherence tomography and fundus autofluorescence correlation in tubercular serpiginouslike choroiditis 
Objective
This study aims to describe changes in high-resolution spectral domain optical coherence tomography (SD-OCT) scans with simultaneous fundus autoflorescence (FAF) signals in tubercular serpiginouslike choroiditis (SLC).
Methods
Simultaneous SD-OCT and FAF imaging of eyes affected with SLC from acute stage until resolution of lesions was obtained using Spectralis HRA+OCT system (Heidelberg Engineering, Heidelberg, Germany).
Patients
Four eyes (three patients) with SLC were prospectively followed.
Results
Acute lesions of SLC (diffusely hyperautofluorescent) corresponded to hyperreflective areas on SD-OCT involving the retinal pigment epithelium (RPE), photoreceptor outer segment tips (POST), inner segment–outer segment (IS/OS) junction, external limiting membrane (ELM), and outer nuclear layer (ONL) with a minimal distortion of inner retinal layers. There was no backscattering from inner choroid. During healing, lesions became discrete with a hypoautofluorescent border and predominant hyperautofluorescence centrally. The hyperreflective fuzzy areas on SD-OCT scans disappeared, and irregular, knobbly elevations of outer retinal layers appeared. The RPE, POST, IS/OS junction, and ELM could not be distinguished. The ONL appeared normal. The choroid showed an increased reflectance. As the lesions healed further over the next 3–6 months, they became predominantly hypoautofluorescent with loss of RPE, POST, IS/OS junction, and ELM in SD-OCT scan.
Conclusion
The SD-OCT provided an insight into the ultrastructural changes in the outer retina during the course of acute SLC lesions. The changes on OCT correlated with abnormal FAF findings.
doi:10.1007/s12348-011-0037-7
PMCID: PMC3223337  PMID: 21847595
Fundus autofluorescence; Spectral domain optical coherence tomography; Tubercular serpiginouslike choroiditis
11.  Solar Retinopathy: A Multimodal Analysis 
Purpose. Solar retinopathy is a rare clinical disturbance, for which spectral-domain optical coherence tomography (SD-OCT) findings are not always consistent. We report on two cases of solar retinopathy and discuss its differential diagnosis. Methods. This is an observational case study. Results. A 12-year-old female was referred to ophthalmology for bilateral scotoma. Visual acuity was 20/50 in both eyes. Fundus examination was unremarkable, except for slight yellowish material in the central macula, bilaterally. SD-OCT revealed juxtafoveal microcystic cavities in the outer retina, interruption of the external limiting membrane and the inner and outer segment junctions, with disorganized material in the vitelliform space. Fundus autofluorescence showed hypoautofluorescence surrounded by a relatively hyperautofluorescent ring, bilaterally. Similar clinical and morphological findings were detected in a 27-year-old male. Conclusions. Solar retinopathy has a subtle presentation and patients often deny sun-gazing. SD-OCT and fundus autofluorescence are noninvasive and useful tools for its diagnosis.
doi:10.1155/2013/906920
PMCID: PMC3583086  PMID: 23476848
12.  Feasibility of a Method for Enface Imaging of Photoreceptor Cell Integrity 
American journal of ophthalmology  2011;152(5):807-814.e1.
Purpose
To report a method for enface imaging of the photoreceptor inner and outer segment junction by spectral domain optical coherence tomography (SDOCT) and describe findings in normal subjects and patients with various retinal diseases.
Design
Observational case series study.
Materials and Methods
SDOCT images were acquired in six normal subjects (44 ± 11 years) and five subjects with retinal diseases (66 ± 22 years). A customized high density SDOCT volume scan was acquired on the retina. SDOCT B-scan images were automatically segmented to extract intensity data along the inner and outer segment junction. Data obtained from the raster B-scans were combined to generate an inner and outer segment enface image in a 4.4 mm × 4.4 mm retinal area, centered on the fovea. The foveal to parafoveal mean intensity ratio was measured and repeatability was determined. An infrared (IR) scanning laser ophthalmoscope (SLO) image was acquired and cropped to provide a field of view similar to the inner and outer segment enface image.
Results
Inner and outer segment enface images generated in normal subjects provided clear visualization of the retinal vasculature, matching the vascular network observed in the IR SLO image. In normal subjects, the foveal to parafoveal mean intensity ratio was 0.88 ± 0.06 and repeatability of measurements was on average 7%. In macular hole, a dark circular region was observed in the inner and outer segment enface image, indicative of photoreceptor cell loss. In age-related macular degeneration, the enface image displayed non-uniform texture corresponding to topographic variations in the inner and outer segment junction. In central serous retinopathy, areas of lower intensity were visible on the enface image, corresponding to regions of prior neurosensory elevation. In cystoid macular edema, reduced intensity was present in the inner and outer segment enface image in areas with increased retinal thickness. In diabetic retinopathy, the inner and outer segment enface image displayed regions of reduced intensity due to edema and/or laser scars.
Conclusion
Detection of intensity abnormalities in the inner and outer segment enface image is useful for monitoring the integrity of photoreceptor cells in the course of disease progression and therapeutic intervention.
doi:10.1016/j.ajo.2011.04.027
PMCID: PMC3200461  PMID: 21764030
13.  Dynamics of Human Foveal Development after Premature Birth 
Ophthalmology  2011;118(12):2315-2325.
Purpose
To determine the dynamic morphological development of the human fovea in-vivo utilizing portable spectral domain optical coherence tomography (SDOCT).
Design
Prospective, observational case series.
Paticipants
31 prematurely born neonates, nine children and nine adults.
Methods
Sixty-two neonates were enrolled in this study. SDOCT imaging was performed after examination for retinopathy of prematurity (ROP) at the bedside in non-sedated infants ages 31-41 weeks post-menstrual-age PMA (PMA=gestational age in weeks + chronological age) and at outpatient follow-up ophthalmic examinations. Thirty-one neonates met eligibility criteria. Nine children and nine adults without ocular pathology served as control groups. Semi-automatic retinal layer segmentation was performed. Central foveal thickness (CFT), foveal to parafoveal (FP) ratio (CFT divided by thickness 1000 μm from the foveal center), and 3D thickness maps were analyzed.
Main Outcomes Measures
In-vivo determination of foveal morphology, layer segmentation, analysis of sub-cellular changes, spatio-temporal layer shifting.
Results
In contrast to the adult fovea, we observed several signs of immaturity in the neonates: a shallow foveal pit, persistence of inner retinal layers (IRL), and a thin photoreceptor layer (PRL) that was thinnest at the foveal center. Three-dimensional mapping showed displacement of retinal layers out of the foveal center as the fovea matured and the progressive formation of the inner/outer segment band in the opposite direction. The FP-IRL ratios decreased as IRL migrated prior to term and minimally after that, while FP-PRL ratios increased as PRL subcellular elements formed closer to term and into childhood. A surprising finding was the presence of cystoid macular edema in 58% of premature neonates which appeared to affect inner foveal maturation.
Conclusions
This study provides the first view into development of living cellular layers of the human retina and of subcellular specialization at the fovea in premature infant eyes using portable spectral domain optical coherence tomography. Our work establishes a framework of the timeline of human foveal development, allowing us to identify unexpected retinal abnormalities that may provide new keys to disease activity, and provide a method for mapping of foveal structures from infancy to adulthood that may be integral in future studies of vision and visual cortex development.
doi:10.1016/j.ophtha.2011.05.028
PMCID: PMC3496560  PMID: 21940051
14.  Deferoxamine retinopathy: spectral domain-optical coherence tomography findings 
BMC Ophthalmology  2014;14:88.
Background
To describe the spectral domain optical coherence tomography (SD-OCT) findings of a patient who developed pigmentary retinopathy following high-dose deferoxamine administration.
Case presentation
A 34-year-old man with thalassemia major complained of nyctalopia and decreased vision following high-dose intravenous deferoxamine to treat systemic iron overload. Fundus examination revealed multiple discrete hypo-pigmented lesions at the posterior pole and mid-peripheral retina. Recovery was partial following cessation of desferrioxamine six weeks later. A follow-up SD-OCT showed multiple accumulated hyper-reflective deposits primarily in the choroid, retina pigment epithelium (RPE), and inner segment and outer segment (IS/OS) junction.
Conclusion
Deferoxamine retinopathy primarily targets the RPE–Bruch membrane–photoreceptor complex, extending from the peri-fovea to the peripheral retina with foveola sparing. An SD-OCT examination can serve as a simple, noninvasive tool for early detection and long-term follow-up.
doi:10.1186/1471-2415-14-88
PMCID: PMC4090392  PMID: 24989140
Spectral domain optical coherence tomography; Deferoxamine; Retinopathy
15.  High-Definition and 3-dimensional Imaging of Macular Pathologies with High-speed Ultrahigh-Resolution Optical Coherence Tomography 
Ophthalmology  2006;113(11):2054.e1-2054.14.
Objective
To assess high-speed ultrahigh-resolution optical coherence tomography (OCT) image resolution, acquisition speed, image quality, and retinal coverage for the visualization of macular pathologies.
Design
Retrospective cross-sectional study.
Participants
Five hundred eighty-eight eyes of 327 patients with various macular pathologies.
Methods
High-speed ultrahigh-resolution OCT images were obtained in 588 eyes of 327 patients with selected macular diseases. Ultrahigh-resolution OCT using Fourier/spectral domain detection achieves ~3-μm axial image resolutions, acquisition speeds of ~25 000 axial scans per second, and >3 times finer resolution and >50 times higher speed than standard OCT. Three scan protocols were investigated. The first acquires a small number of high-definition images through the fovea. The second acquires a raster series of high-transverse pixel density images. The third acquires 3-dimensional OCT data using a dense raster pattern. Three-dimensional OCT can generate OCT fundus images that enable precise registration of OCT images with the fundus. Using the OCT fundus images, OCT results were correlated with standard ophthalmoscopic examination techniques.
Main Outcome Measures
High-definition macular pathologies.
Results
Macular holes, age-related macular degeneration, epiretinal membranes, diabetic retinopathy, retinal dystrophies, central serous chorioretinopathy, and other pathologies were imaged and correlated with ophthalmic examination, standard OCT, fundus photography, and fluorescein angiography, where applicable. High-speed ultrahigh-resolution OCT generates images of retinal pathologies with improved quality, more comprehensive retinal coverage, and more precise registration than standard OCT. The speed preserves retinal topography, thus enabling the visualization of subtle changes associated with disease. High-definition high-transverse pixel density OCT images improve visualization of photoreceptor and pigment epithelial morphology, as well as thin intraretinal and epiretinal structures. Three-dimensional OCT enables comprehensive retinal coverage, reduces sampling errors, and enables assessment of 3-dimensional pathology.
Conclusions
High-definition 3-dimensional imaging using high-speed ultrahigh-resolution OCT improves image quality, retinal coverage, and registration. This new technology has the potential to become a useful tool for elucidating disease pathogenesis and improving disease diagnosis and management.
doi:10.1016/j.ophtha.2006.05.046
PMCID: PMC1939823  PMID: 17074565
16.  Redefining Lamellar Holes and the Vitreomacular Interface: An Ultrahigh-Resolution Optical Coherence Tomography Study 
Ophthalmology  2006;113(3):388-397.
Objectives
To define optical coherence tomographic (OCT) criteria for the diagnosis of a lamellar macular hole, and to increase understanding of lamellar hole pathogenesis by examining fine anatomic features using ultrahigh-resolution optical coherence tomography (UHR OCT).
Design
Retrospective observational case series.
Participants
Nineteen eyes of 18 patients with lamellar holes were imaged with UHR OCT between 2002 and 2004.
Methods
A UHR OCT system was developed for use in the ophthalmology clinic. All 6 UHR OCT images for each eye imaged were examined. Lamellar holes were diagnosed based on a characteristic OCT appearance. Criteria for the OCT diagnosis of a lamellar hole were as follows: (1) irregular foveal contour; (2) break in the inner fovea; (3) intraretinal split; and (4) intact foveal photoreceptors. From 1205 eyes of 664 patients imaged with UHR OCT, and retrospectively reviewed, 19 eyes of 18 patients were diagnosed with a lamellar hole based on these criteria. All 19 eyes were also imaged with standard resolution OCT. Their charts were retrospectively reviewed.
Main Outcome Measures
Standard and ultrahigh-resolution OCT images.
Results
On chart review, clinical diagnosis of a lamellar hole was made in only 7 of 19 eyes (37%). Twelve of 19 eyes (63%) had an epiretinal membrane (ERM) on clinical examination. Ten of 19 eyes (53%) had a posterior vitreous detachment. On UHR OCT, 17 of 19 eyes (89%) had ERMs. Eleven ERMs had an unusual thick appearance on UHR OCT. Due to poor visual acuity, 4 eyes underwent vitrectomy. Only 1 of 4 surgeries (25%) was visually and anatomically successful. Another eye improved visually, but a lamellar hole persisted. One eye progressed to a full-thickness macular hole preoperatively, which reopened after surgery. One eye developed a full-thickness hole postoperatively.
Conclusions
The diagnosis of a lamellar hole can be made based on OCT criteria, which could be applied to both standard and ultrahigh-resolution OCT. The increased resolution of UHR OCT sheds light on the pathogenesis of the lamellar hole. Epiretinal membranes were visualized on UHR OCT in the majority of eyes. Many ERMs had an unusual thick appearance on UHR OCT, which may represent either trapped vitreous or posterior hyaloid, and may help stabilize retinal anatomy. Conversely, ERM contraction may play a role in lamellar hole formation. Vitrectomy surgery was anatomically and visually successful in only 1 of 4 patients, suggesting caution when performing vitrectomy on lamellar holes.
doi:10.1016/j.ophtha.2005.10.047
PMCID: PMC1940046  PMID: 16513456
17.  In vivo visualization of photoreceptor layer and lipofuscin accumulation in stargardt’s disease and fundus flavimaculatus by high resolution spectral-domain optical coherence tomography 
Introduction:
To assess photoreceptor (PR) layer morphology in patients with Stargardt’s disease (STGD) and fundus flavimaculatus (FFM) using high resolution spectral domain optical coherence tomography (HD-OCT; OCT 4000 Cirrus, Humphrey-Zeiss, San Leandro, CA).
Methods:
This was a prospective observational case series. Sixteen consecutive patients with STGD and FFM underwent a complete ophthalmologic examination. Optical coherence tomography examination was performed with HD-OCT, a high-speed (27,000 axial scans per second) OCT system using spectral/Fourier domain detection, with an axial image resolution of 5 μm.
Results:
A total of 31 eyes were included in the study. Transverse loss of the PR layer in the foveal region was shown by HD-OCT. Twenty eyes with clinically evident central atrophy had a disruption of either the Verhoeff‘s membrane (VM) or the layer corresponding to the interface of inner segment (IS) and outer segment (OS) of PR in the foveal region. Among these eyes, 12/20 eyes had a loss of the PR layer (loss of both VM and IS-OS interface) in the foveal region. Eleven eyes (11/31) without clinically evident central atrophy had an intact interface of IS and OS of PR centrally. Moreover, we observed hyperreflective deposits: type 1 lesions located within the retinal pigment epithelium (RPE) layer and at the level of the outer segments of PR, and type 2 lesions located at the level of the outer nuclear layer and clearly separated from the RPE layer. Type 1 lesions alone were associated with absence of loss of the PR layer in the foveal region in all eyes; type 2 lesions were always associated with presence of type 1 lesions, and often (8/12 eyes) associated with loss of the PR layer within the foveal region. Mean best-corrected visual acuity (BCVA) was significantly correlated with loss of the PR layer in the foveal region (P < 0.001), as well as to presence of type 2 flecks (P = 0.03).
Conclusion:
Type 2 deposits in STGD/FFM patients seem to represent a marker of the possible evolution towards foveal atrophy.
PMCID: PMC2801640  PMID: 20054419
fundus flavimaculatus; high definition optical coherence tomography; retinal dystrophy; stargardt’s disease
18.  Comparison of Ultrahigh- and Standard-Resolution Optical Coherence Tomography for Imaging Macular Hole Pathology and Repair 
Ophthalmology  2004;111(11):2033-2043.
Purpose
To compare ultrahigh-resolution optical coherence tomography (UHR-OCT) technology to a standard-resolution OCT instrument for the imaging of macular hole pathology and repair; to identify situations where UHR-OCT provides additional information on disease morphology, pathogenesis, and management; and to use UHR-OCT as a baseline for improving the interpretation of the standard-resolution images.
Design
Observational and interventional case series.
Participants
Twenty-nine eyes of 24 patients clinically diagnosed with macular hole in at least one eye.
Methods
A UHR-OCT system has been developed and employed in a tertiary-care ophthalmology clinic. Using a femtosecond laser as the low-coherence light source, this new UHR-OCT system can achieve an unprecedented 3-μm axial resolution for retinal OCT imaging. Comparative imaging was performed with UHR-OCT and standard 10-μm resolution OCT in 29 eyes of 24 patients with various stages of macular holes. Imaging was also performed on a subset of the population before and after macular hole surgery.
Main Outcome Measures
Ultrahigh- and standard-resolution cross-sectional OCT images of macular hole pathologies.
Results
Both UHR-OCT and standard-resolution OCT exhibited comparable performance in differentiating various stages of macular holes. The UHR-OCT provided improved imaging of finer intraretinal structures, such as the external limiting membrane and photoreceptor inner segment (IS) and outer segment (OS), and identification of the anatomy of successful surgical repair. The improved resolution of UHR-OCT enabled imaging of previously unidentified changes in photoreceptor morphology associated with macular hole pathology and postoperative repair. Visualization of the junction between the photoreceptor IS and OS was found to be an important indicator of photoreceptor integrity for both standard-resolution and UHR-OCT images.
Conclusions
Ultrahigh-resolution optical coherence tomography improves the visualization of the macular hole architectural morphology. The increased resolution of UHR-OCT enables the visualization of photoreceptor morphology associated with macular holes. This promises to lead to a better understanding of the pathogenesis of macular holes, the causes of visual loss secondary to macular holes, the timing of surgical repair, and the evaluation of postsurgical outcome. Ultrahigh-resolution optical coherence tomography imaging of macular holes that correspond to known alterations in retinal morphology can be used to interpret retinal morphology in UHR-OCT images. Comparisons of UHR-OCT images with standard-resolution OCT images can establish a baseline for the better interpretation of clinical standard-resolution OCT images. The ability to visualize photoreceptors and their integrity or impairment is an indicator of macular hole progression and surgical outcome.
doi:10.1016/j.ophtha.2004.05.021
PMCID: PMC1937401  PMID: 15522369
19.  Morphologic Characteristics of the Outer Retina in Cone Dystrophy on Spectral-domain Optical Coherence Tomography 
Purpose
To investigate the morphologic changes in the outer retina of patients with cone dystrophy, using spectral-domain optical coherence tomography (SD-OCT).
Methods
The medical records of 15 cone dystrophy patients examined from January 2007 to January 2012 were reviewed retrospectively. All patients underwent ophthalmic evaluation including best-corrected visual acuity (BCVA), color vision testing, fundus examination, full-field standard electroretinography (ERG), multifocal (mf) ERG, and SD-OCT. Qualitative and quantitative SD-OCT data and ERG responses were analyzed and compared among the patient categories and the normal control group.
Results
There were 4 major categories of SD-OCT findings, based on the status of the ellipsoid portion of the photoreceptor inner segment (ISe), outer segment (OS) contact cylinder, and retinal pigment epithelium (RPE) layer. Category 0 showed no structural abnormalities. Category 1 showed foveal ISe loss and obscurity of the border between the ISe band and the external limiting membrane (ELM). Category 2 showed foveal thinning and focal foveal ISe disruption with an intact ELM. Category 3 showed foveal thickening and perifoveal disruption of the ISe layer. Category 1 to 3 showed OS contact cylinder layer absence and RPE thickening. The patients in category 0 tended to be younger (mean, 10.0 years) than those in categories 1 to 3 (mean, 17.6 years), although this difference was not statistically significant. Category 1 to 3 patients exhibited statistically significant thinning of the central retina and outer nuclear layer and thickening of the RPE layer relative to the category 0 and normal control group. There was a significant correlation between the central foveal thickness and BCVA in the patients with cone dystrophy. ERG and mfERG responses did not differ significantly among the different cone dystrophy categories.
Conclusions
The morphologic features of cone dystrophy as revealed by SD-OCT, could be categorized as either normal or 1 of 3 different types of outer retinal changes. The presence of normal retinal structures in young cone dystrophy patients with functional impairment (category 0) indicates that electrophysiologic studies are superior to current imaging modalities for the early diagnosis of cone dystrophy. The characteristic SD-OCT findings in cone dystrophy patients may aid in differential diagnosis and be useful for future research on the pathology of cone dystrophy.
doi:10.3341/kjo.2013.27.1.19
PMCID: PMC3550307  PMID: 23372375
Cone dystrophy; Electroretinography; Photoreceptor cells; Spectral-domain optical coherence tomography
20.  Assessment of Artifacts and Reproducibility across Spectral and Time Domain Optical Coherence Tomography Devices 
Ophthalmology  2009;116(10):1960-1970.
PURPOSE
To report the frequency of optical coherence tomography (OCT) scan artifacts and compare macular thickness measurements, inter-scan reproducibility and inter-device agreeability across three spectral / Fourier domain (SD) OCTs (Cirrus HD-OCT, RTVue-100 and Topcon 3D-OCT 1000) and one time domain (TD) OCT (Stratus OCT).
DESIGN
Prospective, non-comparative, non-interventional case series.
PARTICIPANTS
52 patients seen at New England Eye Center, Tufts Medical Center retina service between February and August 2008.
METHODS
Two scans were performed for each of the SD-OCT protocols: Cirrus macular cube 512×128, RTVue (E)MM5 and MM6, Topcon 3D macular and radial, in addition to one TD-OCT scan via Stratus macular thickness protocol. Scans were inspected for six types of OCT scan artifacts and analyzed. Inter-scan reproducibility and inter-device agreeability were assessed by intraclass correlation coefficients (ICCs) and Bland-Altman plots, respectively.
MAIN OUTCOME MEASURE
OCT image artifacts, Macular thickness, Reproducibility, Agreeability.
RESULTS
TD-OCT scans contained a significantly higher percentage of clinically significant improper central foveal thickness (IFT) post-manual correction (greater than or equal to 11 μm change) compared to SD-OCT scans. Cirrus HD-OCT had a significantly lower percentage of clinically significant IFT (11.1%) compared to the other SD-OCT devices (Topcon 3D: 20.4%, Topcon Radial: 29.6%, RTVue (E)MM5: 42.6%, RTVue MM6: 24.1%; p= 0.001). All three SD-OCT had central foveal subfield thicknesses significantly greater than TD-OCT post manual correction (p< 0.0001). All 3 SD-OCT demonstrated a high degree of reproducibility in the central foveal region (ICC= 0.92 to 0.97). Bland-Altman plots showed low agreeability between TD- and SD-OCT scans.
CONCLUSIONS
Cirrus HD-OCT scans exhibited the lowest occurrence of any artifacts (68.5%), IFT (40.7%) and clinically significant IFT (11.1%) compared to all other OCT devices examined, while Stratus OCT scans exhibited the highest occurrence of clinically significant IFT compared to all 3 SD-OCT examined. Significant differences in macular thickness occurred among SD- and TD-OCT. All SD-OCT examined revealed high reproducibility in the central foveal subfield (ICC 0.92 to 0.97). Higher scan density and speed obtainable with SD-OCT appear to improve reproducibility. Although software breakdown occurred to a variable degree with different commercial OCT, further work on improving segmentation algorithm to decrease artifacts is warranted.
doi:10.1016/j.ophtha.2009.03.034
PMCID: PMC2757525  PMID: 19592109
21.  Spectral domain optical coherence tomographic findings at convalescent stage of acute zonal occult outer retinopathy 
Purpose
To describe the morphology of the retina at the convalescent stage of acute zonal occult outer retinopathy (AZOOR) from images obtained by spectral domain optical coherence tomography (SD-OCT).
Methods
The visual fields, electroretinograms (ERGs), and OCT images were reviewed in two women aged 24 and 33 years. The patients were followed for one and four years, respectively.
Results
In both cases, the anterior and posterior segments were almost normal, although both patients had a sudden unilateral vision decrease and photopsia. Goldmann perimetry revealed enlarged blind spots and scotomas. The ERGs were reduced in both cases. SD-OCT showed that the junction of the inner and outer segment, the IS/OS line, of the photoreceptors was irregular or lost in the affected retinas. The retina in these areas was thinner due to a decrease in the thickness of both the outer nuclear layer (ONL) and inner nuclear layer (INL) in Case 2.
Conclusions
The decrease in retinal thickness at the convalescent stage of AZOOR is most likely due to a shortening of not only the photoreceptors and ONL but also to a thinning of the INL in a severe case.
PMCID: PMC2724032  PMID: 19684865
AZOOR; SD-OCT; IS/OS; ONL
22.  Ultrahigh-Resolution Optical Coherence Tomography in Patients with Decreased Visual Acuity after Retinal Detachment Repair 
Ophthalmology  2006;113(4):666-672.
Objective
To assess microstructural changes in the retina that may explain incomplete visual recovery after anatomically successful repair of rhegmatogenous retinal detachments (RD) using ultrahigh-resolution optical coherence tomography (UHR OCT).
Design
Retrospective observational case series.
Participants
Seventeen patients with decreased visual acuity after RD repair. Twelve patients had macula-involving and 5 had macula-sparing RDs.
Methods
The UHR OCT prototype capable of ~3 μm axial resolution was developed for clinical use. The UHR OCT images through the center of the fovea in 17 patients with visual complaints after RD surgery were obtained. Patients were either postoperative patients from the New England Eye Center or tertiary referrals. Baseline visual acuity, preoperative lens status, location of retinal detachment, macular involvement, and postoperative visual acuity were recorded.
Main Outcome Measures
The UHR OCT images after RD repair.
Results
The UHR OCT images were obtained 1 to 84 months (median, 5 months) postoperatively. The mean preoperative logarithm of the minimum angle of resolution (logMAR) visual acuity was 1.37 (Snellen equivalent, 20/390). The mean postoperative logMAR visual acuity was 0.48 (Snellen equivalent, 20/60). Anatomical abnormalities that were detected included distortion of the photoreceptor inner/outer segments (IS/OS) junction in 14 of 17 patients (82%), epiretinal membranes in 10 of 17 patients (59%), residual subretinal fluid in 3 of 17 patients (18%), and cystoid macular edema in 2 of 17 patients (12%). Of the 5 patients with preoperative macula-on detachments, 4 had distortion of the outer retina after RD repair.
Conclusions
The higher resolution of UHR OCT facilitates imaging of the IS/OS junction. Therefore, UHR OCT is able to confirm prior histopathologic findings that damage to photoreceptor outer segments may occur as a consequence of retinal detachment. This may explain poor postoperative visual acuity in eyes with anatomically successful repair.
doi:10.1016/j.ophtha.2006.01.003
PMCID: PMC1940045  PMID: 16581427
23.  Characterizing the Phenotype and Genotype of a Family With Occult Macular Dystrophy 
Archives of ophthalmology  2012;130(12):1554-1559.
Objective
To characterize the phenotype of a white patient with occult macular dystrophy (OMD) and her clinically unaffected family members and to determine whether similar mutations were present in the RP1L1 gene in this family. Occult macular dystrophy is a rare macular dystrophy with central cone dysfunction hidden behind a normal fundus appearance that has been attributed to a mutation in the retinitis pigmentosa 1–like 1 (RP1L1) gene in 4 Japanese families.
Methods
In this observational cross-sectional study of 1 white family with OMD, patients meeting the clinical criteria for OMD and their family members were evaluated by use of multifocal electroretinography, the Farnsworth D-15 color vision test, automated perimetry, spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence, and fundus photography. Fluorescein angiography was performed only on the proband. Members of this family were screened for genetic mutations in the RP1L1 gene.
Results
In the family studied, the clinically affected proband was noted to have loss of the foveal outer segments and absence of bowing of the inner segment/outer segment junction on SD-OCT scans. In addition, 1 clinically unaffected family member also demonstrated loss of the foveal photoreceptor outer segments and, therefore, decreased bowing of the inner segment/outer segment junction on SD-OCT scans. The fundus autofluorescence images of the eyes of the proband and her family members were normal. Although mutations in the RP1L1 gene have been identified in sporadic and autosomal dominant OMD pedigrees, no mutations in the RP1L1 gene were found in any of the participants.
Conclusions
Loss of the outer segments of foveal photoreceptors can be detected and quantified by use of SD-OCT in patients with OMD. Similar findings are present in some clinically unaffected family members and may represent subclinical manifestations of the disease. Although mutations in the RP1L1 gene have been described in several Japanese families with OMD, there were no such mutations in this white family of European descent, which suggests that inherited OMD is a genetically heterogeneous disorder.
doi:10.1001/archophthalmol.2012.2683
PMCID: PMC4114073  PMID: 23229695
24.  Macular Thickness Measurements in Normal Eyes with Time Domain and Fourier Domain Optical Coherence Tomography 
Retina (Philadelphia, Pa.)  2009;29(7):980-987.
Purpose
To compare macular thickness measurements using time domain optical coherence tomography (OCT) and Fourier domain OCT (FD OCT).
Methods
Thirty-two eyes from 32 normal patients underwent complete ophthalmic evaluation. Macular scanning using the StratusOCT and the RTVue-100 OCT were performed for a total of 3 times each on the same visit. The average retinal thicknesses of the 9 macular sectors as defined by the Early Treatment Diabetic Retinopathy Study (ETDRS), along with the foveal center point and macular volume, were recorded. The standard deviation, the coefficient of variation, and the intraclass correlation coefficient were calculated for each parameter studied. Comparisons were made between the two OCTs in terms of retinal thicknesses measurements, their reproducibility, and macular regional differences. Correlations between retinal thickness and demographic variables (age and gender) were also investigated. Due to known differences in segmentation algorithms of the two OCTs, software calipers were used to measure the distance from the internal limiting membrane to the photoreceptor inner segment--outer segment junction at the foveal center point on all RTVue scans in order to allow a more fair comparison.
Results
The RTVue yielded greater retinal thickness measurements in nearly all macular subfields compared to the StratusOCT. Even after accounting for differences in segmentation algorithms, significant disparities were still evident with the RTVue measurements less than those of the StratusOCT at the foveal center. On both machines, the macula was thinnest at the fovea and thickest within the 3mm ring. There were some consistent regional variations in macular thickness evident on both OCTs. Compared to the StratusOCT, the RTVue generally had lower coefficients of variation and higher intraclass coefficients, suggesting better reproducibility. Age and gender also appeared to be important determinants in some macular thickness parameters.
Conclusion
Compared with StratusOCT, the RTVue FD OCT yields greater retinal thickness measurements with greater reproducibility, presumably due to different segmentation algorithms, increased sampling density, and greater resolution. However, regional differences across the macula can be consistently observed with both devices.
doi:10.1097/IAE.0b013e3181a2c1a7
PMCID: PMC2749962  PMID: 19584656
Fourier-domain; macular thickness; optical coherence tomography; time-domain
25.  In vivo characterization of ischemic retina in diabetic retinopathy 
Objective
The aim of this article is to characterize pathomorphologic changes within particular layers of fluorescein angiographically ‘ischemic’ compared to ‘nonischemic’ retina in patients with diabetic retinopathy.
Methods
Cross-sectional images of ischemic retinal areas were obtained using Heidelberg Spectralis optical coherence tomography (OCT). Presumed retinal ischemia was defined as focal hypofluorescence in early or early and late phase fluorescein angiography. Pathomorphologic changes on OCT were evaluated and the thickness of retinal layers measured and compared with nonischemic retina at corresponding topographic locations in a matched-pairs design based on 22 eyes (mean age 64 ± 14).
Results
In all eyes, based on spectral domain-OCT cross-section images, the retina layers in ischemic retinal areas could be segmented. Total retinal thickness was significantly increased in ischemic compared to nonischemic areas (381 ± 94 μm versus 323 ± 89 μm, P = 0.005). Middle retinal layers (inner nuclear layer, outer plexiform layer, and outer nuclear layer) were significantly thickened in retinal ischemic areas (215 ± 82 μm versus 168 ± 62 μm, P = 0.002). The inner retinal layers (retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer) showed a nonsignificant change (117 ± 53 μm versus 98 ± 30 μm), while the outer layers were slightly thinned (photoreceptors plus retinal pigment epithelium layer; 51 ± 9 μm versus 57 ± 8 μm, P = 0.02) in ischemic versus nonischemic retina.
Conclusions
Ischemic diabetic retina seems to be thickened due to thickening of, in particular, middle retinal layers, which can be measured with high-resolution OCT.
doi:10.2147/OPTH.S13850
PMCID: PMC3033002  PMID: 21311655
OCT; Spectralis OCT; fluorescein angiography; diabetic retinopathy; ischemic retina; retinal thickness; retinal layers

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