Clinical Utility of Multimodal Imaging to Assess Macular Changes in Usher Syndrome: A Transversal Study

Abstract

Purpose Usher syndrome (USH) is an autosomal recessive disorder that presents with varying degrees of visual loss related to Retinitis Pigmentosa. In most of the developing countries, initial diagnosis is based on clinical criteria and supported by multimodal imaging. The objective of this study is to identify changes in retinal morphology through retinal imaging that could be a diagnostic parameter of disease’s progression. Methods a transversal study was conducted to examine patients referred with a presumed clinical diagnosis of USH using visual acuity, campimetry, retinography and quantitative OCT and OCTA parameters. Eyes were divided into two groups according to visual acuity (BCVA): Group 1 BCVA > 0.5 and Group 2 BCVA < 0.5, allowing comparative analysis between eyes with different degrees of visual loss from the disease. Results The final sample consisted of 18 patients. Group 1 showed an increased central macular thickness (p = 0.003, µd 64µm), a decrease in FAZ area and perimeter (p = 0.002, µd -0,43 mm2; p = 0,004 µd -1,45mm); an increase in central, internal and total macular vessel perfusion density (p = 0.002, µd 9.57%; p = 0.001, µd 10.24%; p = 0.001, µd 10.40%). This study compared the difference between the quantitative values between OD and OS, finding a mean difference in FAZ’s circularity index of -0.05µm (p = 0.024). Conclusion The OCT and OCTA parameters exhibit notable alterations in USH, which vary based on the patient's visual acuity. Evaluation of retinal quantitative parameters presented in this study can be used as tools for monitoring the evolution and future studies in treatment of USH, especially its complications.