Agreement among ophthalmologists in evaluating fluorescein angiograms in patients with neovascular age-related macular degeneration for photodynamic therapy eligibility (FLAP-study)

Abstract

Objective To determine intraobserver and interobserver variation for classifying types of choroidal neovascularizations (CNV) in exudative age-related macular degeneration (ARMD). Design Intraexaminer and interexaminer reliability study. Participants Digital high-quality fluorescein angiograms of 40 patients with neovascular ARMD were evaluated independently by 16 retinal specialists. Main outcome measures Fluorescein angiographies were presented in two randomized sequences (series A and B) to each masked reader for classification of type of CNV into classic, occult, or mixed with classic component of less or greater 50%. Agreement was evaluated by calculating kappa statistics (κ) and intraclass correlation coefficients. Results The mean κ coefficient was 0.64 ± 0.11 for intraobserver variation, with a range from 0.44 to 0.89. For interobserver variation the intraclass correlation coefficients was calculated as 0.66 (95% confidence interval [CI] 0.56, 0.77) for series A and as 0.55 (95% CI 0.43, 0.67) for series B. Conclusions Angiographic classification of CNV secondary to ARMD can vary considerably not only between observers but also for repeated evaluation by the same observer. Because various current and emerging treatments including photodynamic therapy are based on specific angiographic characteristics, accurate interpretation will become more important.