Ophthalmological disorders in rural areas of Crete: a geospatial analysis

INTRODUCTION Estimation of the prevalence of vision impairment in a population can be performed using epidemiological research. The purpose of this study was to measure, using spatial statistics, the prevalence of ophthalmologic disease identified at visits of the Mobile Ophthalmologic Unit (MOU) of the Vardinogiannion Eye Institute of Crete (VEIC) to villages in Crete. The study also aimed to estimate increased 'risk' of ophthalmological disease according to demographic and location factors and, thus, use the present findings as a basis for planning future services. METHODS Estimation of risks for cataract, glaucoma, and refractive errors were assessed by multiple logistic regression models in order to measure the effect of demographic (age, sex) and location (province, distance from nearest ophthalmologist) parameters. Spatial analysis was applied in order to produce a density and probability density map of ophthalmologic disorders using kriging interpolation methods. RESULTS Newly diagnosed cataracts and refractive errors were found more frequently in locations greater than 70 km from the nearest ophthalmologist (respectively, OR = 6.0 [95% CI = 1.637-9.482]; OR = 27.4 [20.038-39.028] p-value = 0.004). Those aged >60 years had higher risk for all eye abnormalities: cataracts (OR = 0.7; 95% CI = 0.238-0.938), glaucoma (OR = 1.6; 95% CI = 1.227-2.037), and refractive errors (OR = 0.5; 95% CI = 0.183-0.829). CONCLUSION The present study supports the use of local policies and preventive measures in rural areas of Crete in order to improve rural health standards. Some insights concerning the effectiveness of future visits of MOUs are provided, guided by spatial analysis.