In preparation for the planning of a regional prevention of
blindness programme, a population-based survey of
blindness and
eye disease was conducted in two provinces (Diyarbakir and Mardin) of southeast Turkey. A stratified cluster random sampling procedure was used to select 8,571 persons. The main objectives of the survey were to assess the population need for basic ophthalmic services, both in rural and in rapidly growing urban communities, and to secure baseline data for subsequent evaluation of the programme. The prevalence of
visual impairment (best binocular vision poorer than 6/ 18) was estimated at 1.9% with 95% confidence limits of 1.6% and 2.1%, amounting to 29,400 +/- 4500 visually imparied persons in the regional population of 1.6 million. The prevalence of
blindness (best vision poorer than 3/60) was 0.4%, and an estimated 1.5% had
low vision (best vision poorer than 6/18, but not blind). Compared to the
blindness prevalence of 0.2% in the European Economic Community (EEC), the age-standardised prevalence of
blindness in southeast Turkey was 8 times as high. The main causes of
blindness in the sample were
cataract (50%),
corneal opacity (15%),
glaucoma (12%), phthisis (6%) and
optic atrophy (6%).
Cataract and
refractive errors were responsible for 52% and 26% of the
low vision, respectively. Acute inflammatory
trachoma was prevalent in a number of rural and urban communities, affecting an estimated 25,900 people in the region. The need for basic ophthalmic services was estimated for the two provinces. Some 26,600 were in need of
cataract surgery, 4,400 needed eyelid surgery for
trachoma-induced
entropion, and 28,600 required
spectacles to improve their visual acuity to 6/18 or better. More than half of the current burden of severe visual loss in the two provinces of southeast Turkey is potentially remediable through the provision of
cataract surgery and of
spectacles to correct
aphakia. The survey findings suggest that as the age structure of the regional population approaches that of the EEC through the "ageing trend', a four-fold increase in the burden of
blindness might be expected, unless improvements are made in curative and preventive ophthalmic services in parallel with the general development that improves survival.