Prevalence of and risk factors for cornea guttata in a population-based study in a southwestern island of Japan: the Kumejima study.

OBJECTIVE: To examine the prevalence of and risk factors for cornea guttata in a rural southwestern island of Japan.

DESIGN: 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.

RESULTS: 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.

CONCLUSIONS: 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.