Six-year incidence of ocular hypertension in a South Indian population: the Chennai eye disease incidence study.

AIMS To report the 6-year incidence and risk factors for ocular hypertension (OHT) in a population-based study in southern India. METHODS 6 years after baseline evaluation, 56.9% subjects (participants:non-participants, 4421:3353) were re-examined at the base hospital. Incident OHT was defined as an intraocular pressure above the 97.5th centile for the population with no evidence of glaucoma in the 2852 phakic subjects, 40 years or older. Subjects with trauma, laser or incisional surgery at baseline or follow-up were excluded (total exclusions: 1569). RESULTS Incidence of OHT at 6 years was 62/2852 subjects (2.17% (95% CI 1.64% to 2.71%, men:women, 36:26)). Incidence was higher in the rural cohort as compared with the urban cohort (80.6% vs 19.4%, p<0.001). A higher baseline intraocular pressure (with increasing OR: 16-18 mm Hg (OR 4.0, 95% CI 2.1 to 7.9), 19-21 mm Hg (OR 11.4, 95% CI 5.7 to 22.9), 22-24 mm Hg (OR 42.6, 95% CI 11.0 to 164.8, in the urban cohort)) and increasing age (50-59 years (OR 1.9, 95% CI 1.1 to 3.3), 70 years and above (OR 3.6, 95% CI 1.2 to 10.6)) were significantly associated risk factors for incident OHT. CONCLUSIONS A significant proportion of this normal population converted to OHT. A higher incidence of conversion was seen in the rural population.