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 97.5^th 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.