Objectives: To determine inter- and intraobserver agreement among Canadian retina specialists in their angiographic classification of choroidal neovascularization and their decision to treat with photodynamic therapy. Agreement was also determined between retina specialists and a Reading Center.

Methods: Forty retina specialists graded 24 cases of exudative age-related macular degeneration on two occasions separated by 6 months. Participants were asked to categorize the choroidal neovascularization and indicate if they would treat with photodynamic therapy. Agreement was determined for decision to treat and for interpretation of the fluorescein angiogram. Angiographic interpretation by participants was compared with that of the Reading Center.

Results: The kappas among the 40 participants for lesion categorization and treatment decision were 0.43 (95% confidence interval: 0.36-0.52) and 0.29 (95% confidence interval: 0.18-0.42), respectively. The kappa for intraobserver agreement was 0.57 (95% confidence interval: 0.50-0.64) for lesion categorization and 0.58 (95% confidence interval: 0.43-0.74) for treatment decision. The mean percent agreement with the Reading Center for lesion categorization was 65.4%.

Conclusions: There was moderate interobserver agreement for choroidal neovascularization categorization and poor agreement among Canadian retina specialists for decision to treat with photodynamic therapy. There was moderate intraobserver agreement for both treatment decision and lesion categorization. There was moderate agreement between observers and the Reading Center for angiographic choroidal neovascularization categorization.