Abstract
Purpose: :
Dry AMD is the most common cause of vision loss in the developed world. It is characterized by accumulation of macular drusen, focal hyperpigmented RPE, and geographic atrophy. No generally accepted treatment exists. However, rescue of RPE and/or photoreceptor cells would probably delay progression of AMD. The purposes of the present experiment were to 1) measure the rate of progression of dry AMD, and 2) propose patient selection criteria for pilot testing of a drug to prevent progression of dry AMD.
Methods: :
Medical charts from 51 patients with a mean age of 76 years were mined for: severity of AMD using a standardized worsening scale from 0 to 6, visual acuity (VA, Snellen), medications/procedures to treat eye diseases, date of eye examinations, age, and sex. Groups of eyes with AMD scores 2, 3, or 4 were compared, using separate eyes as individual data points and excluding those with cataract.
Results: :
VA (logMAR) was positively correlated with AMD score (P < 0.0001, n=66). In the grade 3 group, logMAR increased 0.17 + 0.32 (n = 14) units after two years. Eighty eight % of the eyes progressed 1 or more AMD scores with a mean time for progression from grade 3 to 4 of 1.8 + 2.0 years. Predictive statistical analysis showed that comparing two groups of grade 3 AMD patients (drug-treated versus non-treated), each containing 222 patients, for two years would allow detection of drug inhibition as low as 50% (P < 0.05).
Conclusions: :
Functional VA measurements were correlated with structural AMD scores, and indicate that both indicators will be useful in clinical trials on AMD. Recruiting only grade 3 patients would be ideal for time- and cost-efficient, pilot drug efficacy studies on moderately progressing dry AMD.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: natural history • clinical (human) or epidemiologic studies: health care delivery/economics/manpower