RISK OF VISUAL IMPAIRMENT ATTRIBUTABLE TO OCULAR HISTOPLASMOSIS

Purpose: To compare 15-year incidence rates of visual impairment and v ision-threatening conditions between cases with ocular histoplasmosis and controls residing in the same endemic community. Methods: Controls and cases with and without disciform lesions who were between 30 and 69 years of age when selected, interviewed, and examined in 1970 were reinterviewed and reexamined in 1985. Results: Of the 252 cases and co ntrols examined in 1970, 216 were still alive in 1985. Of these, 202 ( 94%) were interviewed; 197(91%) underwent visual acuity measurement; a nd 173 (80%) were examined by a study ophthalmologist. Both in 1970 an d in 1985, cases with disciform macular lesions of ocular histoplasmos is had a higher prevalence of both unilateral and bilateral visual imp airment and blindness. Although prevalence of visual impairment and bl indness in 1985 was similar among controls and cases of ocular histopl asmosis without disciform lesions, this group of cases had about twice the incidence of visual impairment as that of controls. However, the 95% confidence intervals on estimates of relative risks were broad and included unity. No new disciform lesions attributable to ocular histo plasmosis were found in 28 eyes of 18 cases free of them in 1970 or am ong 148 controls. Conclusions: The 15-year risk of visual impairment a nd blindness appears to be somewhat higher among adults aged 30 years and older who have only peripheral atrophic scars characteristic of oc ular histoplasmosis than among individuals without such scars who live in the same endemic community. Adults who already have a disciform le sion attributed to ocular histoplasmosis in one eye are at low risk of development of a disciform lesion in the fellow eye later in life.