Prevalence and predictors of refractive error and spectacle coverage in Nakuru, Kenya: a cross-sectional, population-based study.

A cross-sectional study was undertaken in Nakuru, Kenya to assess the prevalence of refractive error and the spectacle coverage in a population aged ≥50 years. Of the 5,010 subjects who were eligible, 4,414 underwent examination (response rate 88.1 %). LogMAR visual acuity was assessed in all participants and refractive error was measured in both eyes using a Topcon auto refractor RM8800. Detailed interviews were undertaken and ownership of spectacles was assessed. Refractive error was responsible for 51.7 % of overall visual impairment (VI), 85.3 % (n = 191) of subjects with mild VI, 42.7 % (n = 152) of subjects with moderate VI, 16.7 % (n = 3) of subjects with severe VI and no cases of blindness. Myopia was more common than hyperopia affecting 59.5 % of those with refractive error compared to 27.4 % for hyperopia. High myopia (+5.0 DS). Of those who needed distance spectacles (spectacle coverage), 25.5 % owned spectacles. In conclusion, the oldest, most poor and least educated are most likely to have no spectacles and they should be specifically targeted when refractive services are put in place

Helpful developments and technologies for school eye health programmes.

School eye health programmes provide a unique opportunity to positively influence the health of 700 million children globally. The impact of school eye health (SEH) goes far beyond good vision— it encompasses education, social development and economic productivity

N-acetylcarnosine (NAC) drops for age-related cataract.

BACKGROUND: Cataract is the leading cause of world blindness. The only available treatment for cataract is surgery. Surgery requires highly-trained individuals with expensive operating facilities. Where these are not available, patients go untreated. A form of treatment that did not involve surgery would be a useful alternative for people with symptomatic cataract who are unable or unwilling to undergo surgery. If an eye drop existed that could reverse or even prevent progression of cataract, then this would be a useful additional treatment option.Cataract tends to result from oxidative stress. The protein, L-carnosine, is known to have an antioxidant effect on the cataractous lens, so biochemically there is sound logic for exploring L-carnosine as an agent to reverse or even prevent progression of cataract. When applied as an eye drop, L-carnosine cannot penetrate the eye. However, when applied to the surface of the eye, N-acetylcarnosine (NAC) penetrates the cornea into the front chamber of the eye (near to where the cataract is), where it is metabolised into L-carnosine. Hence, it is possible that use of NAC eye drops may reverse or even prevent progression of cataract, thereby improving vision and quality of life. OBJECTIVES: To assess the effectiveness of NAC drops to prevent or reverse the progression of cataract. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2016), Embase (January 1980 to June 2016), Allied and Complementary Medicine Database (AMED) (January 1985 to June 2016), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to June 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 June 2016. We handsearched the American Society of Cataract and Refractive Surgery (ASCRS) and the European Society of Cataract and Refractive Surgeons (ESCRS) meetings from 2005 until September 2015. SELECTION CRITERIA: We planned to include randomized or quasi-randomised controlled trials where NAC was compared to control in people with age-related cataract. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We identified two potentially eligible studies from Russia and the United States. One study was split into two arms: the first arm ran for six months, with two-monthly follow-up; the second arm ran for two years with six-monthly follow-up. The other study ran for four months with a data collection point at the start and end of the study only. A total of 114 people were enrolled in these studies. The ages ranged from 55 to 80 years.We were unable to obtain sufficient information to reliably determine how both these studies were designed and conducted. We have contacted the author of these studies, but have not yet received a reply. Therefore, these studies are assigned as 'awaiting classification' in the review until sufficient information can be obtained from the authors. AUTHORS' CONCLUSIONS: There is currently no convincing evidence that NAC reverses cataract, nor prevents progression of cataract (defined as a change in cataract appearance either for the better or for the worse). Future studies should be randomized, double-masked, placebo-controlled trials with standardised quality of life outcomes and validated outcome measures in terms of visual acuity, contrast sensitivity and glare, and large enough to detect adverse effects

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

Towards a workflow driven design for mHealth devices within temporary eye clinics in low-income settings

Only a small minority of mobile healthcare technologies that have been successful in pilot studies have subsequently been integrated into healthcare systems. Understanding the reasons behind this discrepancy is crucial if such technologies are to be adopted. We believe that the mismatch is due to a breakdown in the relation between technical soundness of the original mobile health (mHealth) device design, and integration into healthcare provision workflows. Quantitative workflow modelling provides an opportunity to test this hypothesis. In this paper we present our current progress in developing a clinical workflow model for mobile eye assessment in low-income settings. We test the model for determining the appropriateness of design parameters of a mHealth device within this workflow, by assessing their impact on the entire clinical workflow performance

The diabetic retinopathy screening workflow : potential for smartphone imaging

Complications of diabetes mellitus, namely diabetic retinopathy and diabetic maculopathy, are the leading cause of blindness in working aged people. Sufferers can avoid blindness if identified early via retinal imaging. Systematic screening of the diabetic population has been shown to greatly reduce prevalence and incidence of blindness within the population. Many national screening programmes have digital fundus photography as their basis. In the past five years several techniques and adapters have been developed that allow digital fundus photography to be performed using smartphones. We review recent progress in smartphone - based fundus imaging and discuss its potential for integration into national systematic DR screening programmes. Some systems have produced promising initial results with respect to their agreement with reference standards. However further multi-site trialling of such systems’ use withi n implementable screening workflows is required if an evidence base strong enough to affect policy change is to be established. If this were to occur national diabetic retinopathy screening would, for the first time, become possible in low-and middle-income settings where cost and availability of trained eye-care personnel are currently key barriers to implementation. As diabetes prevalence and incidence is increasing sharply in these settings, the impact on global blindness could be profound

Helpful developments and technologies for school eye health programmes

School eye health programmes provide a unique opportunity to positively influence the health of 700 million children globally. The impact of school eye health (SEH) goes far beyond good vision— it encompasses education, social development and economic productivity

Systematic bias in real-world tonometry readings based on laterality?

AIMS: In research settings, the first eye examined tends to have a higher intraocular pressure (IOP) than the second. We sought to verify whether clinicians in Yorkshire, UK, measure IOP in right eyes before left and whether such behavioural factors affect IOP readings at the population level. METHODS: We observed 128 IOP measurements taken by 28 ophthalmologists using Goldmann applanation tonometry (GAT) over a 4-month period in 2018, recording which eye was examined first. All IOP measurements on electronic patient records for Leeds Teaching Hospitals NHS Trust, UK, between January 2002 and June 2017 were extracted, yielding IOP readings for 562,360 eyes, analysed for evidence of systematic bias in IOP measurement. RESULTS: Right eye IOP was measured before left in 112/128 observations (87.5% (95% CI: 75.2%-94.2%)). For IOP measured by GAT, there was no statistically significant difference (p = 0.121) between right and left eye IOP (mean IOP 16.95 and 16.96 mmHg, respectively). Even values of IOP were reported more frequently than odd values (136,503/214,628 (63.6%) were even). Identical IOP readings for both eyes were recorded in 124,392/254,380 patients (48.9%) who had both eyes measured. CONCLUSIONS: Our study found no IOP difference based on laterality, but strong evidence of certain trends associated with IOP measurement by GAT, such as a preference for even values and the same IOP being recorded for both left and right eyes. Such effects may be explained by behavioural aspects of GAT and suggest that there are substantial opportunities for improvement in the way GAT is utilised in real world settings