Baseline Risk Factors for Incidence of Blindness in a South Indian Population: The Chennai Eye Disease Incidence Study

• Published in: Investigative ophthalmology & visual science Vol. 55; no. 9; p. 5545
• Main Authors: Vijaya, Lingam, Asokan, Rashima, Panday, Manish, Choudhari, Nikhil S., Ramesh, Sathyamangalam Ve, Velumuri, Lokapavani, Boddupalli, Sachi Devi, Sunil, Govindan T., George, Ronnie
• Format: Journal Article
• Language: English
• Published: United States 07.08.2014
• Subjects: Adult; Age Distribution; Aged; Blindness - epidemiology; Cohort Studies; Female; Humans; Incidence; India - epidemiology; Male; Middle Aged; Risk Factors; India; epidemiology; cataract; blindness; incidence; India
• ISSN: 1552-5783; 1552-5783
• DOI: 10.1167/iovs.14-14614

To report the baseline risk factors and causes for incident blindness. Six years after the baseline study, 4419 subjects from the cohort underwent a detailed examination at the base hospital. Incident blindness was defined by World Health Organization criteria as visual acuity of less than 6/120 (3/60) and/or a visual field of less than 10° in the better-seeing eye at the 6-year follow-up, provided that the eye had a visual acuity of better than or equal to 6/120 (3/60) and visual field greater than 10° at baseline. For incident monocular blindness, both eyes should have visual acuity of more than 6/120 (3/60) at baseline and developed visual acuity of less than 6/120 (3/60) in one eye at 6-year follow-up. For incident blindness, 21 participants (0.48%, 95% confidence interval [CI], 0.3-0.7) became blind; significant baseline risk factors were increasing age (P = 0.001), smokeless tobacco use (P < 0.001), and no history of cataract surgery (P = 0.02). Incident monocular blindness was found in 132 participants (3.8%, 95% CI, 3.7-3.8); it was significantly more (P < 0.001) in the rural population (5.4%, 95% CI, 5.4-5.5) than in the urban population (1.9%, 95% CI, 1.8-1.9). Baseline risk factors (P < 0.001) were increasing age and rural residence, and no history of cataract surgery was a protective factor (P = 0.03). Increasing age was a significant risk factor for blindness and monocular blindness. No history of cataract surgery was a risk factor for blindness and a protective factor for monocular blindness.