Abstract
Purpose: :
To describe fundus autofluorescence (AF) patterns in choroidal neovascularization secondary to age–related macular degeneration (AMD) before and after photodynamic treatment (PDT).
Methods: :
Out of 117 patients the study population consisted of consecutive 68 eyes from 68 patients (in 35 patients quality of AF images was poor and in another 14 patients complicated subretinal hemorrhage made judgment of AF patterns impossible), who where indicated for PDT after standard fluorescein angiography. Of those patients 52 showed completely classic choroidal neovascularization (CNV), 7 occult with no classic CNV and another 9 patients predominantly classic CNV according to classification of the TAP study group. Standardized PDT was performed and patients were examined 2–3 months later. Angiography and autofluorescence measurements were performed using the Heidelberg Retina Angiograph (HRA, Heidelberg, Germany). Preoperative and postoperative angiographic and autofluorescence images were evaluated and compared.
Results: :
At baseline AF was mainly decreased in areas of completely classic CNV (79%), but showed a regular (n=2) or mottled pattern (n=5) in angiographically occult CNV. A normal or slightly increased AF was seen at the rim of the classic lesions. One to 5 PDTs (mean 1.93) were performed in all patients. Three months after first PDT there was a clearly enhanced AF decay in the area of classic CNV (83%), whereas AF of the junctional zone was significantly increased (85%), thus membrane demarcation was markedly improved (90%). These patterns stayed constant even after several PDTs. In most cases CNV size enlarged after first PDT (56%). After PDT for occult CNVs a transformation into classic CNV with residual leakage and need for further PDT was observed (6/7) showing the described AF patterns. No change of AF was detected for one occult CNV, which stayed occult after PDT. For the mixed type of CNV both described patterns of AF distribution were found.
Conclusions: :
Especially classic CNVs reveal distinct characteristics of significantly decreased AF presumably due to their localization above the RPE level leading to blockage of AF. AF patterns after PDT included enhanced CNV demarcation due to an AF decay in the area of CNV and an AF increase in the junctional zone suggesting reactive RPE changes. AF might be an interesting tool to distinguish non–invasively between classic and occult CNV in AMD and to monitor changes after PDT.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • age-related macular degeneration • retinal pigment epithelium