Abstract
Purpose: :
Geographic atrophy (GA) is a cause of severe visual loss in patients with advanced dry age-related macular degeneration (AMD). It has a marked impact on the quality of life of the elderly population and represents a large unmet medical need. The purpose of this study is to determine the rate of progression of GA lesions over time and to assess predictive baseline characteristics in patients enrolled in a prospective, natural history study.
Methods: :
Inclusion criteria include age ≥ 55 years, at least a single GA lesion of ≥1.25 mm2, a total lesion size ≤ 17.5 mm2, best-corrected visual acuity (BCVA) of 35 letters or greater in the study eye, and drusen of ≥ 63 µm or GA in the fellow eye. Eyes are evaluated at baseline using BCVA, complete ophthalmic examination, color fundus photography (CF), fundus autofluorescence (FAF) imaging and fluorescein angiogram and at every 6 months for 18 months by FAF and CF. The primary outcome measure is the anatomical enlargement rate of GA lesions quantified in FAF images.
Results: :
As of December 2008, recruitment is ongoing in the GAP study. Preliminary baseline data were available for 257 patients and 6-month follow-up data were available for 48 patients. At baseline the mean age of patients was 77.3 ± 7.5 years and the mean BCVA was 60.7 ± 14.2 letters. While 26.9% of eyes had unifocal GA lesions, 72.0% showed multifocal patches of GA. Abnormal perilesional FAF patterns (N=235) were classified into focal (12, 5.1%), banded (17, 7.2%), patchy (5, 2.1%), branching (76, 32.3%), fine granular grainy (66, 28.1%), fine granular with peripheral punctated spots (6, 2.6%) and trickling (15, 6.4%). The distribution of patterns was similar to that reported in the FAM study1. The mean lesion size was 6.8 ± 4.7 mm2 (N=48) at baseline and lesions grew on average by 0.65 mm2 during 6 months.
Conclusions: :
Completion of this study will provide further understanding of the natural history of GA progression. The data will be helpful in designing future treatment trials to evaluate novel therapies for slowing progression of geographic atrophy.
Clinical Trial: :
www.clinicaltrials.gov NCT00599846
Keywords: clinical (human) or epidemiologic studies: natural history • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • age-related macular degeneration