Purpose:
To investigate the long term progression of age-related cataract in the Age-Related Eye Disease Study (AREDS).
Methods:
AREDS participants were evaluated for the cataract types of nuclear, cortical, and posterior subcapsular (PSC) using a standardized grading scheme based on retroillumination and slit-lamp lens photographs taken at baseline, 2 years after enrollment, and annually thereafter. Primary outcome was cataract progression, defined as a type-specific opacity grade increase from a baseline cataract status of none or mild to a grade of clinically important cataract defined as either surgery for cataract or presence of "moderate cataract":≥4.0 for nuclear, ≥10% involvement within the full visible lens for cortical, and ≥5% involvement of the central 5-mm circle of the lens for PSC. Cox regression analysis was used to assess risk factor associations and adjusted progression rates for these cataract outcomes. The Wei-Lin-Weissfeld method was used to take into account the correlation between eyes.
Results:
This study was a clinic-based cohort of 4425 persons (8676 eyes) aged 55-80, with an average of 8.9± 2.9 years of follow up. The number of eyes with no or mild cataract available at baseline for analyses include: 7600 for nuclear, 7412 for cortical, and 8168 for PSC. All 8676 eyes were included in the cataract surgery analysis.The rates of cataract progression are displayed in the following table:
Conclusions:
Progression to moderate cataract or cataract surgery was highest in the oldest age group. Females had a higher rate of nuclear and cortical cataract progression compared with males. Males had a higher rate of PSC progression. The results of this study of three types of age-related cataract may provide rates of progression that are important in designing future epidemiologic studies and clinical trials of prevention and treatment of age-related cataracts.
Clinical Trial:
www.clinicaltrials.gov NCT00000145
Keywords: cataract • clinical (human) or epidemiologic studies: natural history • clinical (human) or epidemiologic studies: risk factor assessment