Visual impairment in an Australian population

Purpose: To describe the age- and gender-specific rates of blindness and visual impairment (VI). Methods: The Melbourne Visual Impairment Project is a population-based sample of residents aged 40 and over, recruited from 9 pairs of census collector districts who attended a local screening centre. Distance visual acuity was assessed on a LogMAR chart; near acuity on a LogMAR reading card; and visual fields on a Humphrey Field Analyser. Results: 3271 Melbourne residents were studied, 83% of eligible, (aged 40 to 98 years, 54% female). Visual acuity: overall 56% wore distance correction, this was more common in females and the elderly. The mean number of LogMAR letters read was higher for males, both on presentation and after refraction. With refraction 61% of people improved by at least one line of acuity in their better eye. When controlling for age, the odds of improving ≥ 1 line were 1.44 (95% CI:1.01-2.06) in men vs. women. Age-standardised blindness (<3/60) rates after correction were 0.06% in males and 0.21% in females. Near vision: Direct age-standardised rates of near visual acuity did not vary significantly by gender (χ²=3.3, p=0.19). 98% could read N8. Visual fields: Age standardised blindness rates due to visual field loss (functional area <25% in central r=20° circle) were 0.38% in males and 0.25% in females. Conclusion: Overall rates of blindness are relatively low, but visual impairment that often could be rectified by simple refraction is surprisingly common. This highlights the need to target eye care service programs especially to older females.