To conduct a rapid assessment of cataract surgical services to estimate the prevalence and causes of blindness and visual impairment in members of the population aged ⩾40 years in the Limbe urban area, Cameroon.
Clusters of 50 people aged ⩾40 years were sampled with probability proportionate to size. Compact segment sampling was used to select households within clusters. All eligible people had their visual acuity (VA) measured by an ophthalmic nurse. An ophthalmologist examined people with VA<6/18.
2215 people were examined (response rate = 92.3%). The prevalence of bilateral blindness was 1.1% (95% CI: 0.7–1.5%), 0.3% (0.1–0.6%) for severe visual impairment and 3.0% (2.0–4.0%) for visual impairment. Posterior‐segment disease was the leading cause of blindness (29%), followed by cataracts (21%) and optic atrophy (21%). Cataracts were the most common cause of severe visual impairment (43%) and visual impairment (48%). Most cases of blindness (50%), severe visual impairment (57%) and visual impairment (78%) were avoidable (that is, they were caused by cataracts, refractive error, corneal scar, onchocerciasis or phthisis/no globe). The cataract surgical coverage was relatively high, although 57% of eyes operated upon had a poor outcome (presenting VA<6/60).
Although the prevalence of blindness was relatively low, most of the cases were avoidable. The implementation of an effective eye‐care programme remains a priority in the Limbe urban area.
Blindness; Cameroon; survey; cataract; prevalence; urban
Two recent studies reported over 70% of the patients with non‐arteritic anterior ischaemic optic neuropathy (NAION) had sleep apnoea syndrome (SAS) diagnosed by overnight polysomnography. The current study used the Sleep Apnea scale of the Sleep Disorders Questionnaire (SA‐SDQ) to evaluate this association.
A matched case‐control study was conducted among 73 cases of NAION matched on age and gender to 73 controls without a history of NAION. Information regarding demographics, medical conditions, health behaviours and SAS was obtained via a telephone questionnaire that included the SA‐SDQ. Conditional logistic regression was used to calculate odds ratios (OR) and the 95% confidence intervals (CI) for the association between NAION and the SA‐SDQ.
Cases were significantly more likely to report symptoms and characteristics consistent with SAS than controls (OR 2.62; 95% CI 1.03 to 6.60) when adjusted for medical and health behaviour characteristics.
The results of this study suggest that patients with SAS are at increased risk of NAION. Additional research in a larger population is needed to confirm the observed results and validate the use of the SA‐SDQ in patients with NAION.
To evaluate the effectiveness of 2.5% povidone‐iodine eye drops (PIED) compared with ophthalmic chloramphenicol (OC) for preventing neonatal conjunctivitis.
2004 neonates were enrolled from three rural hospitals in a trachoma endemic area. They were randomly assigned to receive either PIED (n = 1024) or OC (n = 974). Infectious conjunctivitis was confirmed by laboratory methods, including specific search for Chlamydia trachomatis by polymerase chain reaction assay.
During the first 48 hours after birth, PIED and OC had similar efficacy against bacterial conjunctivitis (95% confidence interval (CI), −0.031 to −0.004; p = 0.01); from day 3 to day 15, PIED was 6% less effective than OC (95% CI, −0.058 to −0.006; p = 0.01); after day 16 there was no significant difference between the groups (95% CI, −0.022 to 0.041; p = 0.57). However, the risk of C trachomatis conjunctivitis was increased in neonates receiving PIED prophylaxis (relative risk = 1.99 (95% CI, 1.07 to 3.71), log‐rank p = 0.029). Ocular side effects were rare and self limiting in both groups (p = 0.223).
PIED seems to increase the risk of acquiring chlamydial conjunctivitis in neonates. Additional measures are required to prevent mother to fetus transmission of chlamydial infection during pregnancy, delivery, and after birth.
; trachoma; blindness
The current study was designed to determine whether intravitreal injection of tacrolimus (FK506) modulates the gene expression of neurotrophic factor‐related molecules in the retina from eyes with induced experimental autoimmune uveoretinitis (EAU) in rats.
Rats were immunised with interphotoreceptor retinoid binding protein peptide (R14) and given intravitreal injection of tacrolimus on day 12 after immunisation. As control, immunised rats received intravitreal injection of vehicle. On day 15 after immunisation, changes in the genetic programme associated with neuroprotection and inflammatory responses in the retinas from both groups were determined by DNA microarray analyses and confirmed by real‐time PCR analyses.
The gene expression of inflammatory responses was markedly reduced in tacrolimus‐treated eyes. Genes for molecules associated with neuroprotection (oestrogen receptor, erythropoietin receptor, gamma‐aminobutyric acid receptor, protein kinase C, glial cell line‐derived neurotrophic factor receptor, fibroblast growth factor and neuropeptide Y receptor) were upregulated in the retinas from tacrolimus‐treated eyes.
Intravitreal injection of tacrolimus modulated the genes related to neuroprotection in the retina during the ongoing process of EAU. This treatment may be useful for the neuroprotection of retina with severe uveitis as well as for immunosuppression in the uveitic eyes.
To establish the sensitivity and reliability of objective image analysis in direct comparison with subjective grading of bulbar hyperaemia.
Images of the same eyes were captured with a range of bulbar hyperaemia caused by vasodilation. The progression was recorded and 45 images extracted. The images were objectively analysed on 14 occasions using previously validated edge‐detection and colour‐extraction techniques. They were also graded by 14 eye‐care practitioners (ECPs) and 14 non‐clinicians (NCLs) using the Efron scale. Six ECPs repeated the grading on three separate occasions
Subjective grading was only able to differentiate images with differences in grade of 0.70–1.03 Efron units (sensitivity of 0.30–0.53), compared to 0.02–0.09 Efron units with objective techniques (sensitivity of 0.94–0.99). Significant differences were found between ECPs and individual repeats were also inconsistent (p<0.001). Objective analysis was 16× more reliable than subjective analysis. The NCLs used wider ranges of the scale but were more variable than ECPs, implying that training may have an effect on grading.
Objective analysis may offer a new gold standard in anterior ocular examination, and should be developed further as a clinical research tool to allow more highly powered analysis, and to enhance the clinical monitoring of anterior eye disease.
To evaluate the repeatability and reproducibility of anterior chamber angle measurement obtained by anterior segment optical coherence tomography.
Twenty‐five normal subjects were invited for anterior chamber angle imaging with an anterior segment optical coherence tomography (OCT) on one randomly selected eye in three separate visits within a week. Each eye was imaged three times under room light (light intensity = 368 lux) and three times in the dark during the first visit. In the subsequent visits, each eye was imaged once in the light and once in the dark. The angle opening distance (AOD 500) and the trabecular–iris angle (TIA 500) were measured by a single observer. Only the nasal angle was analysed. Intrasession and intersession within‐subject standard deviation (Sw), precision (1.96×Sw), coefficient of variation (CVw) (100×Sw/overall mean), and intraclass correlation coefficient (ICC) were calculated to evaluate repeatability and reproducibility.
For intrasession repeatability, the Sw, precision, CVw and ICC of AOD/TIA were 45 μm/2.4°, 88 μm/4.7°, 5.8%/4.8% and 0.97/0.95 in the light; and 45 μm/2.1°, 88 μm/4.2°, 7.0%/5.0% and 0.98/0.97 in the dark. For intersession reproducibility, the Sw, precision, CVw and ICC of AOD/TIA were 79 μm/3.5°, 155 μm/6.8°, 10.0%/7.0%, 0.91/0.89 in the light; and 64 μm/3.4°, 124 μm/6.6°, 9.9%/7.8% and 0.95/0.92 in the dark.
The anterior segment OCT demonstrated reliable anterior chamber angle measurement in different lighting conditions with good repeatability and reproducibility.
National screening programmes for diabetic retinopathy using digital photography and multi‐level manual grading systems are currently being implemented in the UK. Here, we assess the cost‐effectiveness of replacing first level manual grading in the National Screening Programme in Scotland with an automated system developed to assess image quality and detect the presence of any retinopathy.
A decision tree model was developed and populated using sensitivity/specificity and cost data based on a study of 6722 patients in the Grampian region. Costs to the NHS, and the number of appropriate screening outcomes and true referable cases detected in 1 year were assessed.
For the diabetic population of Scotland (approximately 160 000), with prevalence of referable retinopathy at 4% (6400 true cases), the automated strategy would be expected to identify 5560 cases (86.9%) and the manual strategy 5610 cases (87.7%). However, the automated system led to savings in grading and quality assurance costs to the NHS of £201 600 per year. The additional cost per additional referable case detected (manual vs automated) totalled £4088 and the additional cost per additional appropriate screening outcome (manual vs automated) was £1990.
Given that automated grading is less costly and of similar effectiveness, it is likely to be considered a cost‐effective alternative to manual grading.
To present a new technique using autologous dermis graft at the time of enucleation or evisceration to replace the ocular surface area lost when the corneal scleral button is excised.
A retrospective, interventional, non‐comparative case series of patients who had an autologous dermis graft placed to assist in closure of Tenon's capsule and conjunctiva at the time of enucleation or evisceration. Medical records were reviewed and the following variables were recorded: age, sex, history of previous ocular surgery or radiation treatment, indication for surgery, type of surgery, laterality, type of orbital implant, size of implant, length of follow up, and complications.
Nine patients were identified (three male, six female) Five had enucleation with implant placement and four had evisceration with implant placement. Four individuals received unwrapped porous polyethylene spherical implants, three received silicone implants, and two received hydroxylapatite implants. Follow up ranged from 30 to 112 weeks (mean (SD), 61 (28) weeks). No operative or early complications were observed. One patient who had enucleation after two rounds of brachytherapy for uveal melanoma developed subsequent late exposure of the implant. There were no complications involving the graft donor site.
This small series shows that the use of a dermis graft is a safe and effective new technique to facilitate orbital rehabilitation. It is hypothesised that the extra surface area produced with a dermis graft preserves the fornices and allows a larger implant. It may also allow the implant to be placed more anteriorly which assists with both implant and prosthesis motility.
enucleation; evisceration; dermis graft; orbital implant; anophthalmos
Van Leewen et al's work provides valuable data, moving us closer to determining whether preschool vision screening can be justified
The excess risk of bilateral visual impairment (BVI; bilateral visual acuity <0.5) among individuals with amblyopia is an argument for screening for amblyopia, but data are scarce.
The risk was estimated by determining the incidence of BVI in the Rotterdam Study, a population‐based cohort of subjects aged 55 years or over (n = 5220), including 192 individuals with amblyopia (3.7%). Using a multistate lifetable, the lifetime risk and excess period spent with BVI were determined.
The relative risk of BVI for amblyopes was 2.6 (95% confidence interval 1.4–4.5). For individuals with amblyopia, the lifetime risk of BVI was 18%, whereas they lived on average 7.2 years with BVI. For non‐amblyopic individuals, these figures were 10% and 6.7 years, respectively.
Amblyopia nearly doubles the lifetime risk of BVI and affected individuals spent an extra six months with BVI. This study provides data for future cost‐effectiveness analyses.
amblyopia; lifetime risk; visual impairment
Rubella vaccination programmes offer hope in eradicating congenital rubella syndrome in developing countries
To assess the efficacy of automated “disease/no disease” grading for diabetic retinopathy within a systematic screening programme.
Anonymised images were obtained from consecutive patients attending a regional primary care based diabetic retinopathy screening programme. A training set of 1067 images was used to develop automated grading algorithms. The final software was tested using a separate set of 14 406 images from 6722 patients. The sensitivity and specificity of manual and automated systems operating as “disease/no disease” graders (detecting poor quality images and any diabetic retinopathy) were determined relative to a clinical reference standard.
The reference standard classified 8.2% of the patients as having ungradeable images (technical failures) and 62.5% as having no retinopathy. Detection of technical failures or any retinopathy was achieved by manual grading with 86.5% sensitivity (95% confidence interval 85.1 to 87.8) and 95.3% specificity (94.6 to 95.9) and by automated grading with 90.5% sensitivity (89.3 to 91.6) and 67.4% specificity (66.0 to 68.8). Manual and automated grading detected 99.1% and 97.9%, respectively, of patients with referable or observable retinopathy/maculopathy. Manual and automated grading detected 95.7% and 99.8%, respectively, of technical failures.
Automated “disease/no disease” grading of diabetic retinopathy could safely reduce the burden of grading in diabetic retinopathy screening programmes.
To assess the role of clusterin in retinal vascular development and in free radical damage in vivo and in vitro.
The expression of clusterin, von Willebrand factor (vWF), flk‐1, heat shock protein 27 (Hsp27) and heat shock protein 70 (Hsp70) was examined in the retinas of developing mice and oxygen‐induced retinopathy (OIR) mice by immunofluorescence staining and western blot analysis. Hydrogen peroxide (H2O2)‐pretreated human retinal endothelial cells (HREC) and astrocytes were cultured in the presence or absence of exogenous clusterin, and then the cell viability was measured using the MTT assay and DAPI staining.
Clusterin was expressed mainly in the inner retina and co‐localised with vWF, an endothelial cell marker. During the mouse developmental process, clusterin expression was decreased, which was similar to the expression of flk‐1, vWF and Hsp27. Furthermore, in the OIR model, clusterin expression changed in a similar way to both vWF and Hsp27. Under hypoxic conditions, clusterin expression increased in HREC and astrocytes. In H2O2‐pretreated HREC and astrocytes, clusterin protected against apoptotic cell death.
These results suggest that clusterin is associated with protection from apoptotic retinal cell death in retinal development and in free radical damage.
Combining primary posterior capsulorhexis (PPC) and posterior optic buttonholing (POBH) in cataract surgery is an innovative approach to prevent after‐cataract formation effectively and to increase postoperative stability of the intraocular lens (IOL). The present study was designed to compare the postoperative intraocular flare after cataract surgery with combined PPC and POBH to conventional in‐the‐bag implantation of the IOL.
Fifty consecutive age‐related cataract patients with cataract surgery under topical anaesthesia in both eyes were enrolled prospectively into a prospective, randomised clinical trial. In randomised order, cataract surgery with combined PPC and POBH was performed in one eye; in the other eye cataract surgery was performed conventionally with in‐the‐bag IOL implantation keeping the posterior lens capsule intact. Intraocular flare was measured 1, 2, 4, 6, 12 and 24 h postoperatively, as well as 1 week and 1 month postoperatively, using a KOWA FC‐1000 laser flare cell meter.
The peak of intraocular flare was observed in POBH eyes and eyes with in‐the‐bag IOL implantation 1 h postoperatively. In both groups, the response was steadily decreasing thereafter. During measurements at day 1, small though statistically significant higher flare measurements were observed in eyes with in‐the‐bag IOL implantation (p<0.05). At 1 week and 1 month postoperatively, intraocular flare measurements were comparable again (p>0.05).
Cataract surgery with combined PPC/POBH showed slightly lower postoperative anterior chamber reaction compared to conventional in‐the‐bag implantation during 4‐week follow‐up, indicating that POBH might trigger somewhat less inflammatory response. This could be explained by the posterior capsule sandwiching between the optic and the anterior capsule, preventing direct contact‐mediated myofibroblastic trans‐differentiation of anterior lens epithelial cells with consecutive cytokine depletion.
To determine the potential influence of genetic factors on the prevalence of myopia in Tehran.
Of 6497 citizens of Tehran sampled from 160 clusters using stratified random cluster sampling, 4565 (70.3%) participated in the study and were referred to a clinic for an extensive eye examination and interview. These were from 1259 nuclear families with the average size of 3.6. Refraction data obtained from 3321 participants aged 16 years and over are presented. Three definitions of myopia, as the spherical equivalent of −0.5, −1, and −2 diopters or less, were used. Familial aggregation of myopia was evaluated with odds ratios and recurrence risk ratios (λR) using a multiple logistic regression with generalised estimating equations (GEE), adjusted for age, sex, height, and education.
Multivariate analyses showed a strong familial aggregation of myopia among siblings (λR ranging from 2.09 to 3.86) and parent–offspring pairs (λR from 1.82 to 3.81) adjusted for age, sex, height, and education. The aggregation increased with higher myopia thresholds and with the use of cycloplegic refraction. The odds ratios for spouse pairs were not significantly different from 1.0. The association of myopia with sex, height, and education (and not age) remained significant in the final GEE2 model.
The findings indicate a relatively high degree of familial aggregation of myopia in the Tehran population, independent of age, sex, height, and education. This residual aggregation may be a result of heredity or of an unmeasured common environmental effect.
familial myopia; myopia; refractive error; recurrence risk
eosinophilic; hypotropia; myositis; orbital; ptosis
Early age‐related macular degeneration (AMD) has been correlated with different functional alterations, but the exact relationship between fundus lesions and overlying sensitivity is not well known. The aim of this study was to compare fundus‐related sensitivity (microperimetry) and fundus autofluorescence (FAF) of the macular area with drusen and pigment abnormalities in early AMD.
13 consecutive patients with early AMD and visual acuity of 20/20 were studied by means of microperimetry, which automatically analyses macular light differential threshold and fixation patterns. Fundus colour photo and FAF of the macular area were recorded on the same day. Microperimetry was exactly (topographically) superimposed over FAF images.
Macular sensitivity significantly decreased over large drusen (11.2 ± 5.6 dB, p<0.0001) and over pigment abnormalities (13.1 ± 3.6 dB, p<0.0001). When both characteristics were present the reduction was greater if compared with its absence (9.6 ± 4.3 versus 15.0 ± 4.5 dB, p<0.0001). Sensitivitity reduction was significant in areas with altered FAF when compared with areas with normal FAF (p<0.0001).
Increased FAF in early AMD has a functional correlate exactly quantified by microperimetry. In retinal areas affected by early AMD retinal sensitivity deteriorates, despite good visual acuity. Microperimetry may allow the early detection of functional impairment caused by these lesions. Both microperimetry and FAF may be useful to monitor AMD progression.