Abstract
Abstract: :
Purpose: To investigate retinal thickness differences between areas with and without leakage on fluorescein angiography in patients with exudative age–related macular degeneration (AMD). Methods: An optical imaging system based on the retinal thickness analyzer (RTA) was used to generate optical section images that encompassed a 6 by 6 mm retinal area. Imaging was performed in one eye of nine patients (mean age, 71 + 6 years) with clinical diagnosis of AMD and choroidal neovascularization (CNV). Patients had either never undergone photodynamic therapy (PDT) (untreated) or had received one or more PDT treatments (treated). The digital optical section images were analyzed to map the retinal thickness with a spatial resolution of 200 microns. In each eye, the retinal thickness map was overlaid on a late phase fluorescein angiogram and six 400 by 400 micron areas were selected. Three areas had distinct leakage and the other three areas were without leakage based on angiograms. These areas were paired so that they would have had comparable thickness in healthy eyes. An average retinal thickness was obtained in areas with and without leakage in each eye. The retinal thickness measurements were compared statistically using Student’s t–Test. Results: A statistically significant difference in retinal thickness was found between areas with leakage (312 + 57 microns) and areas without leakage (276 + 26 microns) on angiography (P = 0.04). In untreated patients, areas with leakage (345 + 50 microns) were thicker than areas without leakage (283 + 19 microns) (P = 0.03). The mean difference in retinal thickness between the 2 areas was 62 + 43 microns. In treated patients, the retinal thickness in areas with and without leakage was similar. The mean retinal thickness difference between the 2 areas was 4 + 4 microns. The ratio of retinal thickness, in areas with leakage to that of areas without leakage, in untreated patients (1.22 + 0.15) was greater than in treated patients (1.02 + 0.02) (P = 0.04). Conclusion:Retinal thickness was increased in areas with leakage on fluorescein angiography in untreated AMD patients, as compared to areas without leakage in untreated eyes and with leakage in treated eyes. Retinal thickness mapping may be a useful tool for quantitative evaluation and monitoring of retinal thickness changes due to CNV and its treatment.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • age–related macular degeneration • choroid: neovascularization