Quantitative Fundus Autofluorescence of the Junctional Zone in Geographic Atrophy due to Reticular Macular Disease (RMD)

Abstract

Purpose : Fundus Autofluorescence (FAF) imaging is a valuable tool for imaging eyes with geographic atrophy (GA) and serves as quantifiable endpoint in clinical trials related to AMD. Different FAF patterns, in the junctional zone surrounding GA, have been described. The purpose of this study was to use quantitative FAF (qAF) to analyze the junctional zone and uninvolved retina in eyes with both GA and reticular macular disease (RMD) which might support previously reported ex vivo findings

Methods : 28 pseudophakic subjects with non-neovascular AMD and 26 controls aged 60 to 90 years were studied. A written informed consent was obtained from each patient. Spectral-domain optical coherence tomography (SD-OCT) and qAF were acquired simultaneously using the Spectralis. Exclusion criteria included diabetes mellitus, anterior segment pathology and concurrent retinal disease.
Mean pericentral qAF (qAF-8) was measured in a subset of 10 eyes of 8 RMD subjects with a range of GA , also compared to controls, using Delori grid. In addition, qAF was calculated by positioning a region-of-intererest (ROI) at 4 different locations including the junctional zone (defined as a ring surrounding the GA area). Structural SD-OCT B-scans through the ROI locations were used to correlate qAF with retinal structure.
The outcome measure was the magnitude of qAF in the perilesional zone of GA. Statistical analysis was performed by SPSS.

Results : 36 eyes of AMD patients were recruited. The mean age of study patients was 83.9 years and 35.7% were men. Mean qAF-8 values were significantly higher in control eyes (132.2 +/- 42.8, p < 0.001) than in AMD eyes (75.9 +/- 23.3). Mean qAF levels were significantly lower in RMD eyes than in control eyes (116.1, p < 0.001). The lowest mean qAF was in the GA subjects (60.7) . ROIs with the highest qAF values, in the junctional zone, were associated with thickening of the RPE-BL-Bruch membrane band on SD-OCT and corresponding to hyper-FAF spots.

Conclusions : There was a difference in qAF-8 with decreasing retinal pigment epithelium (RPE) health and increasing severity of non-neovascular AMD stage in this sample. Focal hyper-qAF values, in the junctional zone, may represent islands of activated RPE seen on SD-OCT for progression in GA as previously reported.The ROI-qAF values distribution, in the GA transition, could become a useful clinical biomarker in AMD

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

C. SD-OCT, F. ROIqAF