Prevalence of age-related macular degeneration in Nakuru, Kenya: a cross-sectional population-based study.

BACKGROUND: Diseases of the posterior segment of the eye, including age-related macular degeneration (AMD), have recently been recognised as the leading or second leading cause of blindness in several African countries. However, prevalence of AMD alone has not been assessed. We hypothesized that AMD is an important cause of visual impairment among elderly people in Nakuru, Kenya, and therefore sought to assess the prevalence and predictors of AMD in a diverse adult Kenyan population. METHODS AND FINDINGS: In a population-based cross-sectional survey in the Nakuru District of Kenya, 100 clusters of 50 people 50 y of age or older were selected by probability-proportional-to-size sampling between 26 January 2007 and 11 November 2008. Households within clusters were selected through compact segment sampling. All participants underwent a standardised interview and comprehensive eye examination, including dilated slit lamp examination by an ophthalmologist and digital retinal photography. Images were graded for the presence and severity of AMD lesions following a modified version of the International Classification and Grading System for Age-Related Maculopathy. Comparison was made between slit lamp biomicroscopy (SLB) and photographic grading. Of 4,381 participants, fundus photographs were gradable for 3,304 persons (75.4%), and SLB was completed for 4,312 (98%). Early and late AMD prevalence were 11.2% and 1.2%, respectively, among participants graded on images. Prevalence of AMD by SLB was 6.7% and 0.7% for early and late AMD, respectively. SLB underdiagnosed AMD relative to photographic grading by a factor of 1.7. After controlling for age, women had a higher prevalence of early AMD than men (odds ratio 1.5; 95% CI, 1.2-1.9). Overall prevalence rose significantly with each decade of age. We estimate that, in Kenya, 283,900 to 362,800 people 50 y and older have early AMD and 25,200 to 50,500 have late AMD, based on population estimates in 2007. CONCLUSIONS: AMD is an important cause of visual impairment and blindness in Kenya. Greater availability of low vision services and ophthalmologist training in diagnosis and treatment of AMD would be appropriate next steps. Please see later in the article for the Editors' Summary

Podoconiosis, trachomatous trichiasis and cataract in northern Ethiopia: a comparative cross-sectional study

Background: Rural populations in low-income countries commonly suffer from the co-morbidity of neglected tropical diseases (NTDs). Podoconiosis, trachomatous trichiasis (both NTDs) and cataract are common causes of morbidity among subsistence farmers in the highlands of northern Ethiopia. We explored whether podoconiosis was associated with cataract or trachomatous trichiasis (TT) among this population. Methods: A comparative cross-sectional study was conducted in East Gojam region, Amhara, Ethiopia in May 2016 . Data were collected from patients previously identified as having podoconiosis and from matched healthy neighbourhood controls. Information on socio- demographic factors, clinical factors and past medical history were collected by an interview-administered questionnaire. Clinical examination involved grading of podoconiosis by examination of both legs, measurement of visual acuity, direct ophthalmoscopy of dilated pupils to grade cataract, and eyelid and corneal examination to grade trachoma. Multiple logistic regression was conducted to estimate independent association and correlates of podoconiosis, TT and cataract. Findings: A total of 700 participants were included in this study; 350 podoconiosis patients and 350 healthy neighbourhood controls. The prevalence of TT was higher among podoconiosis patients than controls (65 (18.6%) vs 43 (12.3%)) with an adjusted odds ratio (OR) 1.55 (95% Confidence Interval (CI) 1.12 - 2.11), p=0.05. There was no significant difference in 3 prevalence of cataract between the two populations with an adjusted OR 0.83 (95% CI 0.55-1.38), p=0.37. Mean best visual acuity was 0.59 (SD +/- 0.06) in podoconiosis cases compared to 0.44 (SD +/- 0.04) in controls, p=< 0.001. The proportion of patients classified as blind was higher in podoconiosis cases compared with healthy controls; 5.6% vs 2.0%; adjusted OR 2.63 (1.08-6.39), P = 0.03. Conclusions Individuals with podoconiosis have a higher burden of TT and worse visual acuity than their matched healthy neighbourhood controls. Further research into the environmental and biological reasons for this co-morbidity is required. A shared approach to managing these two NTDs within the same population could be beneficial

A Review of the Latest Machine Learning Advances in Cataract Diagnosis

Cataract disorder is one of the most common vision disorders in the world. As the average age of the world population increases, many people suffer from it in middle and old age. Timely diagnosis can prevent the reduction of vision and eventually loss of sight. Considering the prevalence of Artificial Intelligence algorithms, especially in the medical industry, they could be used for Cataract diagnosis, IOL determination, and PCO diagnosis. According to the studies, the proposed models for Cataract diagnosis are very accurate. These developed algorithms have been able to make access to ophthalmology services easier and reduce treatment costs significantly

Nutrition and ocular disease in an older Australian cohort : the Blue Mountains Eye Study

Wolfram syndrome patients are mainly characterised by juvenile onset diabetes mellitus and optic atrophy. A synonym is the acronym DIDMOAD: diabetes insipidus, diabetes mellitus, optic atrophy, deafness. Diabetes insipidus and sensorineural high-frequency hearing impairment are important additional features. This rare autosomal recessively inherited neurodegenerative syndrome is caused by mainly inactivating mutations in the WFS1 gene. It is located at chromosome 4p16 and encodes wolframin, a transmembrane protein. No function has yet been ascribed to this protein

Optic nerve head segmentation

Reliable and efficient optic disk localization and segmentation are important tasks in automated retinal screening. General-purpose edge detection algorithms often fail to segment the optic disk due to fuzzy boundaries, inconsistent image contrast or missing edge features. This paper presents an algorithm for the localization and segmentation of the optic nerve head boundary in low-resolution images (about 20 /spl mu//pixel). Optic disk localization is achieved using specialized template matching, and segmentation by a deformable contour model. The latter uses a global elliptical model and a local deformable model with variable edge-strength dependent stiffness. The algorithm is evaluated against a randomly selected database of 100 images from a diabetic screening programme. Ten images were classified as unusable; the others were of variable quality. The localization algorithm succeeded on all bar one usable image; the contour estimation algorithm was qualitatively assessed by an ophthalmologist as having Excellent-Fair performance in 83% of cases, and performs well even on blurred image

Cataract surgery in patients with diabetes

Patients with diabetes account for one eighth of all patients undergoing cataract surgery. Despite this, there is uncertainty over the best operative technique, and although postoperative visual acuity may be poor as a result of macular oedema, the optimal management of this entity is undefined, and natural history data on which to base management are lacking. In this thesis a prospective randomised paired-eye controlled trial comparing phakoemulsification with extracapsular cataract surgery in diabetes identified a lower incidence of capsular opacification and postoperative inflammation, and slightly better visual acuity, in eyes undergoing phakoemulsification. There was no difference in retinopathy progression or incidence of macular oedema. The principal determinants of postoperative visual acuity in each surgical group were the presence of macular oedema at the time of surgery, and to a lesser extent, the severity of retinopathy. A study directed at defining the natural history of postoperative macular oedema attempted to identify predictors of likely spontaneous resolution. Angiographic findings, in particular postoperative optic disc hyperfluorescence, were not predictive. By contrast, clinical examination was a useful predictor, since macular oedema present at the time of surgery showed no tendency to spontaneous resolution, whereas that arising after surgery resolved in three- quarters of eyes by one year. The presence of macular oedema at the time of surgery was the principal determinant of postoperative visual acuity. These findings suggest that macular oedema should be managed expectantly if it arises after surgery, and treated with laser if present at the time of surgery. Phakoemulsification appears to be the preferred surgical approach, but the choice of surgical technique may be less critical to outcome than operating early enough to ensure that cataract does not prevent identification of macular oedema, the presence of which at the time of surgery is associated with poor postoperative visual acuity