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Shin Kadomoto, Muneeswar Gupta nittala, Ayesha Nuri Karamat, Onnisa Nanegrungsunk, Srinivas R Sadda; Detection of Reticular Pseudodrusen on Embossed Color Fundus Photos. Invest. Ophthalmol. Vis. Sci. 2022;63(7):221 – F0068.
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© ARVO (1962-2015); The Authors (2016-present)
Near-infrared reflectance (IR) and fundus autofluorescence (FAF) have been shown to be more sensitiive than traditional flash color fundus photographs (CFP) for detection of reticular pseudodrusen (RPD). IR and FAF images, however, are not always available, particularly in historical datasets which may only contain CFP iamges. In this study, we evaluate whether an embossing image processing technique can improve the detection of RPD on CFP.
Seventy one eyes of 41 subjects (mean age 61.2 ± 5.5 years; range: 53 - 74 years) with RPD were used in this study. Ground truth determination of the presence of RPD in these eyes was established based on the identification of RPD on both IR and FAF images by two independent, masked retinal specialists. A single CFP from the same visit for each case was processed using an embossing technique in which each pixel was replaced by a highlight or a shadow depending on light and dark boundaries present in the original CFP image to yield and embossed photograph (EP). The CFP and EP images were grader separately by two additional masked graders for the presence of RPD. RPD were also classified into two types: dot and ribbon. The dot and ribbon type RPD detection rate on CFP and EP images were assessed indivisually by two other graders. Sensitivity of EP and CFP for detection of RPD was compared to the IR/FAF ground-truth assessment.
Dot type RPD were noted in all 71 eyes in the IR and FAF images, but were detected in only 39 eyes on the CFP images (54.9%), whereas they were detected in 65 eyes from based on the EP images (91.5%). Ribbon type RPD were noted in all 71 eyes in the IR and FAF images, but in only 27 eyes on the CFP images (38.0%) and 14 eyes on the EP images (19.7%). Post-hoc review of the images, confirmed that EP images could visualize dot type RPD lesions not evident on the original CFP image (Figure, arrow). Whereas all 39 eyes in which RPD were noted on CFP also showed RPD on the EP images, EP images demonstrated RPD in 26 of the 32 eyes (81.3%) in which RPD were not visible on the CFP image.
Embossing CFPs can improve the detection of RPD, particurly dot type RPD. As eyes with ribbon type RPD generally also feature dot type RPD, the embossing technique may be a useful tool for better assessing the true frequency of RPD in datasets where only CFP images are available.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.
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