Comparison between fundus autofluorescence images and color fundus photos in patients with late dry age-related macular degeneration

Abstract

Purpose: The purpose was to compare between color fundus photography (CFP) images and fundus autofluorescence (FAF) images of cases with geographical atrophy (GA) about size. To evaluate the relation between different phenotypes of FAF changes and best corrected visual acuity (BCVA) in cases with late dry age-related macular degeneration (AMD) (GA). Materials and Methods: This study was conducted on 18 eyes of 18 patients aged 55 years. Patients unwilling to participate in the study, suffering from hereditary fundus diseases, had previous laser photocoagulation treatment for any cause, were excluded. BCVA using Snellen chart was measured. Retinal imaging including CFP with 50° field camera: Topcon TRC-50 IX - and FAF using spectralis Heidelberg retinal angiograph (HRA) + optical coherence tomography (HRA, Heidelberg Engineering, Germany) were done. All images were optimized and then manually measured using image analysis software (Adobe Photoshop version CS6; Inc., San Jose, California, USA). Images of fundus autofluorescence in cases of late dry AMD were classified to phenotypes at the junctional zone according to the classification of abnormal FAF patterns. Results: According to sex distribution, 33.3% (6 eyes) were males and 66.7% (12 eyes) were females . The mean age of the study participants was 72.89 ± 9.09 years. About surface area of GA, the mean surface area of GA by FAF was 71094.56 ± 21490.53 pixels and by color fundus camera were 46236.56 ± 13153.46 pixels. About FAF phenotypes in late dry AMD cases, Twelve eyes (66.7%) had diffuse pattern, 11.1% (2 eyes) had a none pattern (no specific pattern), and 22.2% (4 eyes) had focal pattern. Color fundus camera underestimated the surface area of GA in cases of late dry AMD. BCVA was best in cases with no specific pattern of autofluorescence at the junctional zone of the GA, followed by cases with focal pattern of hyperautofluorescence while cases with diffuse increases of autofluorescence at the junctional zone showed the worst VA. Conclusions: CFP underestimated the size of the GA, as compared with FAF measured sizes. BCVA was best in cases with no specific pattern of autofluorescence at the junctional zone of the GA, followed by cases with focal pattern of hyperautofluorescence while cases with diffuse increases of autofluorescence at the junctional zone showed the worst VA.