Changes in Letter and Word Acuity with Simulated Cataract and Central Scotoma

Abstract

Age-related maculopathy (ARM) is the leading cause of severe visual impairment among older persons. ARM accounts for 35% of severe visual impairment and 43% of legal blindness in persons 65 years of age or older (Muioz et al., 1997). ARM was the primary diagnosis of the majority of patients referred for low vision services in Cardiff, Wales (Leat & Millodot, 1990), Ontario, Canada (Elliott et al., 1992), and Baltimore, MD (A. Habel, personal communication). ARM causes macular scotomas and is frequently accompanied by other forms of ocular pathology, most notably cataracts. From population-based studies (Mufioz et al., 1997) it is estimated that approximately 35% of patients with ARM also have clinically significant cataract. Recent advances in cataract surgery have resulted in a procedure that is highly effective and involves low risk. Many of the cataracts encountered in eyes with ARM would be removed were there no macular disease. But frequently, cataract surgery is postponed in ARM patients because the surgeon feels that the post-operative improvement in visual acuity would be minimal and would be outweighed by the risk of complications. However, we know of no data that establish how cataracts and macular scotomas jointly affect acuity.