To examine the prevalence of and risk factors for cornea guttata in a rural southwestern island of Japan.
Cross-sectional, population-based study. All residents of Kumejima Island, Japan, located in southwestern Japan (eastern longitude, 126° 48'; northern latitude, 26° 20'), 40 years or older were asked to undergo a comprehensive questionnaire and ocular examination, including noncontact specular microscopy of corneal endothelial cells. Of the 4632 residents, 3762 (81.2%) underwent the examination. The presence of guttata was determined when round or oval dark areas were observed in the specular microscopy images. Cornea guttata was graded from 0 to 4 depending on the total area of dark spots observed on the specular microscopy images. Diagnosis of primary cornea guttata was the main outcome measure.
Of the 3060 eligible residents, 124 (4.1%; 95% confidence interval, 3.4%-4.8%) had cornea guttata in at least 1 eye. Logistic regression analysis with adjustment for age and/or sex indicated that older age, female sex, and thinner central corneal thickness were associated with an increased risk of cornea guttata.
The prevalence of cornea guttata is 4.1% among residents 40 years or older in Kumejima by specular microscopic criteria only, which is lower than the prevalence reported in the Reykjavik, Iceland, study. A higher prevalence may have been determined if slitlamp biomicroscopy findings had been included. Older age, female sex, and a thinner cornea were independently associated with a higher risk of cornea guttata.