Short-Term Progression of Diabetic Hard Exudates Monitored with High-Resolution Camera

Abstract

Purpose: To assess the progression of diabetic hard exudates over an 8-week period, using a high-resolution adaptive optics camera. Design: Prospective observational study. Methods: Five eyes of three patients presenting diabetic maculopathy with hard exudates were studied. An area of clinically visible exudates was imaged sequentially using SD-OCT and high-resolution flood illumination adaptive optics for 2 months, on a weekly basis. A time-lapse video was obtained for each eye studied. Changes in terms of surface, number of free elements (foci), and central macular thickness were recorded. Results: Short-term modifications in terms of disposition, size, and number of exudates were observed. Two patterns of progression were identified: two eyes showed exudate dislocation concomitant with the regression of the underlying macular edema, with hard exudates being progressively replaced by a multitude of smaller foci. These exudates were labeled resorption exudates. In three other eyes with persistent diabetic macular edema, foci aggregated into larger exudates. Conclusion: Diabetic hard exudate changes occurred over a short period of time but were not assessable clinically. Adaptive optics was able to document these subtle changes precisely. Further studies using this imaging modality may improve our understanding of the natural history of exudates and eventually help assess the efficacy of the various treatments available such as lipid-lowering drugs and anti-VEGFs injections.

SSEGEP: Small Segment Emphasized Performance evaluation metric for medical image segmentation

“…In most cases, one of the factors which are used to grade disease severity is the size/volume of the lesion or region of interest. As explained before, the size of the hard exudates increases during the course of diabetic retinopathy [12], and lesions become bigger with stages of cancer like hepatic cancer [18] and breast cancer. Hence, the detection of a tiny lesion helps in the early treatment of associated disease which can thereby avoid unnecessary biopsies.…”

“…The challenges faced in exudate segmentation include drastic variations in size (small to large as an optic disc) and shape and severe imbalanced distribution of classes (more number of nonexudate pixels). The size of diabetic hard exudates changes with the progression of disease [12]; hence, the identification of tiny exudates is very important as it helps in the early treatment. Therefore, the performance evaluation should be in such a way that it emphasizes the smaller exudates more.…”

Adaptive Optics Imaging Technique in Diabetic Retinopathy

“…Among these, microaneurysms [43], microscopic hemorrhages [43][44][45], hard exudates [46,47], edematous cyst walls [45], and modified arteriolar structures [48][49][50] were already morphologically characterized using adaptive optics images (Figures 1 and 2). Offering a fine documentation of retinal lesions, AO imaging technique might become an important instrument for early diagnosis and progression monitorization of DR [51].…”

<p>Long-term changes of retinal pigment epithelium in the eyes with Vogt-Koyanagi-Harada disease observed by adaptive optics imaging</p>

“…Adaptive optics (AO) fundus images are retinal imaging techniques that allow for the improvement of the lateral resolution of retinal images as compared to conventional imaging 9. The AO fundus camera allows not only observation of parafoveal cone photoreceptors, but also microvessel imaging and tracking of minute changes of cell groups, vessel sections, or lesions over time 10–13. The purpose of this study was to observe long-term RPE changes in the eyes of patients with VKH disease using SD-OCT, fundus autofluorescence, and an AO fundus camera.…”