Australian prospective study of cataract surgery and age-related macular degeneration: rationale and methodology

Cataract surgery is the most frequently performed ophthalmic procedure worldwide. While benefits gained from cataract surgery outweigh surgical risks, there have been concerns that older persons may have an increased risk of developing age-related macular degeneration (AMD) after cataract surgery.

The Australian Prospective Study of Cataract Surgery and Age-Related Macular Degeneration Study aims to assess the risk of AMD in a large cohort of older patients following cataract surgery. The current report describes the study rationale, design and methodology.

Longitudinal study.

Approximately 2000 cataract surgical patients aged 65 years or older are being recruited from both public and private sources in western Sydney, Australia.

At study visits, participants are interviewed using standardized questionnaires to obtain information on demographic, medical, and ocular conditions and AMD risk factors, together with data on general health and vision-related quality of life. Eye examinations include visual acuity, intraocular pressure, keratometry and A-scan measurements, plus lens and retinal photography, following pupil dilatation. Retinal photographs taken before cataract surgery, and at 1, 6, 12, and 24 months after surgery are graded for early and late AMD lesions, using the Wisconsin age-related maculopathy grading system. The 1-month post-operative retinal photographs supplement the baseline macular assessment for cases in which cataract occludes a clear view of the macula pre-operatively. It is intended that study participants will be followed for up to five years post-operatively to clarify the question of whether aphakic or pseudophakic, compared to phakic eyes, have a greater risk of developing AMD.