Retinal Neurodegeneration and Visual Acuity Decline in Patients with Chronic Kidney Disease

Introduction: Chronic kidney disease (CKD) has been associated with accelerated retinal neurodegeneration. The purpose of this study is to evaluate the association between retinal neurodegeneration and the best-corrected visual acuity (BCVA) decline in patients with CKD. Methods: Post hoc analysis of two prospective studies. Patients with CKD stage ≥ 3 were enrolled. Macular thickness, peripapillary retinal nerve fiber layer (pRNFL) thickness, and macular ganglion cell complex (GCC) thickness were measured by optical coherence tomography. Eyes were classified into three groups: Group 1, no GCC defect; Group 2, GCC defect confined to parafoveal area; and Group 3, GCC defects extending beyond the parafoveal area. Each group was matched for age, sex, axial length, lens status, and cataract grading. Results: A total of 120 eyes (40 eyes in each group) from 120 patients (age 63.0 ± 10.3 years) were included. The logMAR BCVA was 0.076 ± 0.101, 0.100 ± 0.127, and 0.196 ± 0.191 in Group 1, 2, and 3, respectively. Group 3, but not Group 2, had a significantly worse BCVA than Group 1. In simple linear regression, parafoveal inner retinal thickness, pRNFL thickness, presence of pRNFL defect, GCC thickness, GCC global loss volume, GCC focal loss volume, and GCC defect extending beyond parafoveal area were associated with BCVA. Central subfield retinal thickness (CRT), parafoveal full retinal thickness, and parafoveal outer retinal thickness were not associated with BCVA. In backward stepwise linear regression, age and GCC defects extending beyond the parafoveal area were factors associated with BCVA. Moreover, GCC defect extending beyond parafoveal area was connected with worse BCVA in both phakic and pseudophakic subgroups. Conclusions: GCC defect extending beyond parafoveal area could be an independent biomarker associated with decreased BCVA in patients with CKD. However, macular thinning measured by CRT or parafoveal full retinal thickness might have low discriminative power in determining BCVA.