Purpose: Ultra-wide-field scanning laser ophthalmoscope images aid the ophthalmologists in observing a wide range of the ocular fundus with a 200° angle of view in the eyes. However, one limitation of the images obtained via the device is that the ocular fundus appears darker in the peripheral area than in the central area. Therefore, this study aimed to apply an image sharpening processing software (Fundus Enhancer; Logic and Design Systems) to the ultra-wide-field scanning laser ophthalmoscope images to investigate its usefulness in improving the image clarity by comparing the pre- and post-processing images.
Subjects and methods: Fundus images of eyes with peripheral retinal tears, protiferative diabetic retinopathy, ocular sarcoidosis, and retinitis pigmentosa were captured in the Outpatient Ophthalmology Department, University Hospital, Kyoto Prefectural University of Medicine. The images were first obtained with the use of an ultra-wide-field scanning laser ophthalmoscope and then sharpened with the software. The pre- and post-sharpening images were then randomly displayed on a monitor, and eight first or second-year ophthalmologists were instructed to visually determine the number of abnormal findings in them within 5 seconds. The answers were subsequently compared.
Results: The use of the image sharpening processing software resulted in the peripheral part of the retina, the retinal fissures, and the infectious foci becoming clearly observable in the images, including the retinal blood vessels up to the periphery as well as the range of vasculitis and the boundary of vitreous opacity. Of the total 23 abnormal findings, the mean number visually determined by the eight first or second year training ophthalmologists pre- and post-image sharpening was 10.0±1.6 (mean±standard deviation) and 15.0±1.2, respectively. Thus, the abnormal findings were significantly greater post image sharpening (p=0.016). However, because of the fine image sharpening, 4 normal retinas were incorrectly judged as abnormal.
Conclusion: Application of the image sharpening processing software to fundus images obtained via an ultra-wide-field scanning laser ophthalmoscope may help in clearly visualizing the peripheral abnormalities, which could be helpful in the diagnosis of ocular fundus diseases.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 126: 574-580,2022.