Risk of visual impairment attributable to ocular histoplasmosis. Washington County Follow-up Eye Study Group
B. S. Hawkins and J. P. Ganley
Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD.
PURPOSE: To compare 15-year incidence rates of visual impairment and
vision-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 controls examined in
1970, 216 were still alive in 1985. Of these, 202 (94%) were interviewed;
197 (91%) underwent visual acuity measurement; and 173 (80%) were examined
by a study ophthalmologist. Both in 1970 and in 1985, cases with disciform
macular lesions of ocular histoplasmosis had a higher prevalence of both
unilateral and bilateral visual impairment and blindness. Although
prevalence of visual impairment and blindness in 1985 was similar among
controls and cases of ocular histoplasmosis 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 histoplasmosis were found in 28 eyes of 18 cases free of them in
1970 or among 148 controls. CONCLUSIONS: The 15-year risk of visual
impairment and blindness appears to be somewhat higher among adults aged 30
years and older who have only peripheral atrophic scars characteristic of
ocular histoplasmosis than among individuals without such scars who live in
the same endemic community. Adults who already have a disciform lesion
attributed to ocular histoplasmosis in one eye are at low risk of
development of a disciform lesion in the fellow eye later in life.
