Optical coherence tomography findings following photodynamic therapy of choroidal neovascularization

To develop an optical coherence tomography (OCT) classification system that monitors the response of eyes treated with photodynamic therapy (PDT) with verteporfin for subfoveal choroidal neovascularization (CNV) from age-related macular degeneration (AMD).

Retrospective interventional case series.

Ninety eyes (88 patients) with AMD and predominantly classic subfoveal CNV treated with PDT using verteporfin were identified by a laser log and retrospectively reviewed. Optical coherence tomography and fluorescein angiography (FA) were performed before treatment and at subsequent follow-up examinations in all eyes. Optical coherence tomography findings were evaluated and compared with corresponding FA.

A five-stage OCT classification of eyes treated with PDT was created from the evaluation of 79 total eyes (77 patients). Stage I (two eyes) is recognized within the first week of treatment and demonstrates an acute inflammatory response with increased subretinal fluid. Stage II (28 eyes) represents the restoration of a near-normal fovea contour with diminished subretinal fluid occurring 1 to 4 weeks after treatment. Stage III (79 eyes) occurs between 4 to 12 weeks following treatment and is subdivided into two categories based on the amount of subretinal fibrosis and fluid present. Stage IIIa (15 eyes) contains a greater subretinal fluid to fibrosis ratio indicating an active CNV process. Lesions in stage IIIb (64 eyes) less actively leak and have more prominent fibrosis with minimal intraretinal fluid. Cystoid macular edema defines a stage IV lesion (11 eyes). In stage V lesions (19 eyes) the subretinal fluid resolves with thinning of the retina as well as fibrosis merging with the retinal pigment epithelial layer (RPE).

Optical coherence tomography appears to be useful in monitoring the retinal changes that occur following PDT of CNV and may assist in understanding the changes observed on angiography.