Fractal evaluation in retinographies of individuals with different grades of diabetic retinopathy

• Published in: Revista Brasileira de Oftalmologia 2022-10, Vol.81
• Main Authors: Costa, Edbhergue Ventura Lola, Araújo, Victor Felipe da Silva, Nogueira, Romildo de Albuquerque
• Format: Article
• Language: English
• Subjects: Box-counting and information dimension; Diabetic retinopathy; Fractal dimension; Retinography; Skeletonization; Vascular network
• ISSN: 0034-7280; 1982-8551
• DOI: 10.37039/1982.8551.20220060

ABSTRACT Purpose To evaluate the retinal blood vascular network of the retinographies of patients with different grades of diabetic retinopathy. Methods Ninety Retinographies (MESSIDOR database) were used, with different grades of diabetic retinopathy divided into 4 groups: no retinopathy (n=23), grade one (n=20), grade two (n=20) and grade three (n=27) diabetic retinopathy. The grades of diabetic retinopathy were classified according to the number of microaneurysms, number of hemorrhages and the presence of neovascularization. The images were skeletonized and quantified by fractal methods: dimension of box-counting (Dbc) and information (Dinf). Results The means of Dbc values of groups were around 1.25, without statistically significant difference in the dimension values between groups for whole retina. There was also no statistical difference in Dinf values between groups, whose means ranged between 1.294 ± 0.013 (group of grade 1) and 1.3 ± 0.017 (group of grade 3). The retinographies were divided into regions of equal areas. The fractal values of some retinal regions showed statistical differences, but these differences were not enough to show the sensitivity of fractal methods in identifying diabetic retinopathy. Conclusion The fractal methods were not able to identify the different grades of diabetic retinopathy in retinographies.