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 (kappa) and intraclass correlation coefficients.
Results: The mean kappa 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.