Purpose: To describe the guidelines followed by the Submacular Surgery Trials (SST) Research Group in the interpretation of color fundus photographs and fluorescein angiograms of subfoveal choroidal neovascular lesions evaluated in the SST and to assist ophthalmologists in applying the results of the SST.
Methods: Stereoscopic color fundus photographs and fluorescein angiograms of the study eye and nonstudy eye of 1,015 patients with subfoveal choroidal neovascular lesions secondary to age-related macular degeneration, ocular histoplasmosis syndrome, or idiopathic choroidal neovascularization (CNV) were obtained and graded by certified SST fundus photograph readers at the baseline examination in three randomized clinical trials comparing surgery with observation. Adherence to the inclusion and exclusion criteria and ocular features that might affect visual outcome were documented. Stereoscopic color fundus photography and fluorescein angiography were repeated 1 month after randomization for patients assigned to surgery to provide documentation that surgery was performed and to assess compliance with the surgery protocol. Photographs and fluorescein angiograms of both the study eye and the fellow eye in all patients then were obtained 3 months, 6 months, and 12 months after randomization and then annually up to 48 months. The kappa statistic was used to evaluate interobserver reliability of photograph gradings.
Results: Lesion components at baseline included classic CNV, occult CNV, and features contiguous to CNV, including blood, fibrous tissue, hypofluorescence not corresponding to blood, serous detachment of the retinal pigment epithelium, and prior areas of laser photocoagulation. At follow-up, fluorescein leakage from CNV was assessed peripheral to or within the area of the retinal pigment epithelium abnormality after surgery. The lesion at follow-up could include any of the features identified at baseline as well as retinal pigment epithelium abnormalities, such as mottling of the retinal pigment epithelium with a subtle transition to normal retinal pigment epithelium or a very sharply demarcated, markedly hypopigmented area that was easily distinguished from the surrounding retinal pigment epithelium. kappa statistics for interobserver reliability ranged from good (0.47) to excellent (1.00) for features graded at baseline and follow-up.
Conclusions: Although some of the definitions essential to the interpretation of the SST are similar to those used in the Macular Photocoagulation Study and randomized clinical trials of photodynamic therapy with verteporfin, this guideline provides new information regarding lesion components at baseline as well as standardized descriptions of lesions after submacular surgery. These descriptions from the SST assist in understanding what lesions were studied, when additional treatment was considered after surgery, and how anatomical results should be interpreted.