Aspirin and cataract risk

Abstract

Cumming and Mitchell recently reported on the effects of various medications and cataract development (Ophthalmology 1998;105:1751–8). This study has several methodologic faults that make some of the conclusions unacceptable. In order to assess the effect of various medications, the authors obtained information through a questionnaire. Although patients with severe arthritis or mental disorders are generally aware and can document the intake of medications, those individuals taking occasional analgesics or aspirin are notoriously at fault in remembering the frequency and number of tablets that they ingest. The question asked in this study, “In the past year, how often have you taken an aspirin tablet?” is too vague and subject to inadequate recollection, particularly when a list of ten other medications is requested. The authors have not demonstrated that repetition of the questionnaire at various time intervals during the study has adequate reproducibility. With reference to cataract photographs or color classification of cataracts, the data obtained by the authors fail to address the various cataract combinations, such as posterior subcapsular cataract plus cortical cataract, nuclear cataract plus cortical cataract, and posterior subcapsular cataract plus cortical plus nuclear cataract. Actually, most of the cataracts seen in clinical practice are of combined types. By contrast, a recent study by Christen and coworkers1Christen W.G. Manson J.E. Glynn R.J. et al.Low-dose aspirin and risks of cataract and subtypes in a randomized trial of U.S. physicians”.Ophthalmic Epidemiol. 1998; 5: 133-142Crossref PubMed Scopus (32) Google Scholar addresses the effect of aspirin and risk of cataract in a randomized trial of American physicians. In this study, cataracts that were classified by ophthalmologists were recorded in the charts and correlated in the age groups 40 to 85 with aspirin or no aspirin intake. In this randomized trial in which 95% of cataract subtypes were documented, these authors found a small to moderate benefit of aspirin on cataract development, particularly in the posterior subcapsular type, which produced the greatest decrease in visual acuity. Most significant was the fact that cataract extractions were 19% less frequent in the aspirin-taking physicians than in the placebo group. The cataract type had been determined by medical record review after randomization, and cataract was defined as best-corrected acuity of 20/30 or worse with no acute pathology to explain visual acuity loss. In the study by Cumming and Mitchell, no randomization techniques were used, and visual acuities of patients with and without cataracts are not reported. Furthermore, the authors did not correlate the various types of cataracts with diabetes or steroid intake, which could be used as cataract-at-risk populations. In summary, the loose application of epidemiologic techniques to determine the effects of various medications should not be considered reliable evidence to derive conclusions applicable to discontinued use of systemic medications or medical treatment of cataracts. Asparin and cataract risk: Authors’ replyOphthalmologyVol. 106Issue 4Preview Full-Text PDF