A look at the back of the eye in Kenyan over-50s

Incidence and progression of posterior segment eye disease in a population-based cohort in Kenya

There has been limited focus on posterior segment eye diseases (PSED) by ‘prevention of blindness’ programmes in Africa. Diagnostic challenges surround these conditions and assumptions have been made that they are rare. However, recent surveys indicate that PSED are now responsible for up to one third of visual impairment and blindness in Africa. There is currently a great lack of data on the incidence and progression of PSED in Africa.

This study aims to assess the 5-year incidence and progression of diabetic retinopathy (DR), age-related macular degeneration (AMD) and glaucoma in a Kenyan population aged ≥50 as a follow up of the Nakuru PSED study.

Recruitment: In 2007/8, 4381 participants aged ≥50 years were recruited in a population-based survey in Nakuru, Kenya. They underwent comprehensive ophthalmic examination and fundus image capture. These participants will be re-invited to attend for examination at a local centre, tracked through GPS points taken of their homes. A pilot follow-up study undertaken in January 2009 suggests that 5-years post baseline, at least 65% of the original participants (n=2,848) would be retraced and examined, approximately 2,205 of whom will have gradable images from baseline.

Data Collection: Study participants will each undergo: 1) Visual acuity testing; 2) Visual field assessment; 3) Anterior segment assessment with a slit lamp and measurement of intra-ocular pressure; 4) Retinal photography using a Topcon non-mydriatic camera (dilated); 5) Clinical assessment of posterior segment (dilated) with slit lamp biomicroscopy and OCT); 6) Random blood glucose; and 7) Interview on eye conditions and treatment.

Analysis: The Moorfields Grading Centre will grade retinal images for signs and stages of DR, AMD and glaucoma, using fundus photos. Assessment of disease progression and independent predictors of progression will be undertaken on participants with signs of DR, AMD or glaucoma at baseline. The incidence and predictors of individual PSED development will be analysed on those participants without PSED at baseline.

These data will contribute to establishing diagnostic and prevention strategies, advocacy for provision of resources and identification of high-risk groups. Specifically, Africa is on the cusp of a diabetes epidemic and the impact of DR needs to be assessed. People from African populations appear to be more vulnerable to glaucoma, however, currently incidence and progression data are lacking. The baseline data on AMD suggests this disease presents differently in the Kenyan population, and it is important to assess how it progresses.

As a result of the logistic difficulty of doing this study in remote and hard to access locations, Dr Bastawrous was inspired to develop The Portable Eye Examination Kit (known as Peek). It’s a smartphone, camera adaptor and set of apps for diagnosing conditions that affect the back of the eye. Data from this study have been used to test and compare Peek’s ability to do the job as well and accurately as standard equipment – an essential part of developing the toolkit. Here are some of the outcomes:

• Patients think Peek could transform eye health
  Healthcare workers and eye service decision-makers also give positive reviews for the smartphone suite
• Peek eye test app works as well as visual acuity charts
  Study shows the Peek Acuity app is as fast and accurate as using standard eye charts
• Smartphone eye examination app Peek Retina goes for crowdfunding
  Indiegogo appeal to raise extra funds for Peek to be manufactured and delivered globally
• Peek founder becomes TED Fellow
  Dr Andrew Bastawrous, Fight for Sight/MRC Clinical Research Training Fellow, is made a TED Fellow for 2014

• Bastawrous, A. Increasing access to eye care … there’s an app for that. Peek: smartphone technology for eye health. Int. J. Epidemiol. dyw086 (2016).
• Lodhia, V., Karanja, S., Lees, S. & Bastawrous, A. Acceptability, Usability, and Views on Deployment of Peek, a Mobile Phone mHealth Intervention for Eye Care in Kenya: Qualitative Study. JMIR mHealth and uHealth 4, e30 (2016).
• Bastawrous, A. et al. Clinical Validation of a Smartphone-Based Adapter for Optic Disc Imaging in Kenya. JAMA Ophthalmol 1–8 (2015).
• Bastawrous, A. et al. Development and Validation of a Smartphone-Based Visual Acuity Test (Peek Acuity) for Clinical Practice and Community-Based Fieldwork. JAMA Ophthalmol 133, 930–937 (2015).
• Bastawrous, A. et al. The Nakuru eye disease cohort study: methodology & rationale. BMC Ophthalmol 14, 60 (2014).