Retinal neurodegeneration in patients with end-stage renal disease assessed by spectral-domain optical coherence tomography

Abstract

Spectral-domain optical coherence tomography (SD-oct) represents a reliable tool for retinal layer volume and thickness measurement. the aim of this study was to evaluate retinal changes indicating neurodegenerative processes in patients with end-stage renal disease (eSRD) compared to healthy controls. This was a cross-sectional, single-center study comprising 32 ESRD patients and 38 controls. Sectoral retinal nerve fiber layer (RNFL) thickness and retinal layer volumes were obtained by SD-OCT. Age-and gender-adjusted retinal layer volumes such as total retinal volume (p = 0.037), ganglion cell layer volume (GCL, p = 0.003), ganglion cell layer -inner plexiform layer volume (GCL-IPL, p = 0.005) and inner retinal layer volume (IRL, p = 0.042) of the right eye were lower in ESRD patients. Inner plexiform layer volume of both eyes (IPL, right eye: p = 0.017; left eye: 0.044) was reduced, as was RNFL thickness in the temporal superior sector (right eye: p = 0.016). A subgroup analysis excluding patients with diabetes revealed that GCL (p = 0.014) and GCL-IPL volume of the right eye (p = 0.024) and temporal superior sector of the RNFL scan (p = 0.021) in ESRD patients were still significantly thinner. We observed a decrease in several retinal layer volumes and temporal RNFL thickness indicative of retinal neurodegenerative processes in patients with eSRD.Within the last decade, optical coherence tomography (OCT) of the eye has evolved into a helpful and promising tool to non-invasively evaluate neuronal anatomy and vascular function in patients with various diseases 1-3 . Initially described by Huang et al. in 1991 4 , the first in-vivo application in a healthy volunteer followed in 1993 5 . Since then, various generations of OCT-devices have been developed. The evolution from time-domain to spectral-domain technology has led to an improvement of image quality, accuracy and velocity 6 .Nowadays, OCT has been established as a reliable high-resolution imaging technique that is frequently applied in clinical practice for the measurement of retinal layer thickness in patients with age-related macular degeneration 7-9 , glaucoma 10-13 , diabetic retinopathy 14,15 and other causes of optic neuropathy 16,17 . In addition, the OCT technology has become a valuable diagnostic tool in the assessment of neurodegenerative disorders, allowing the quantification of subtle changes in retinal nerve fiber layer (RNFL) thickness in patients with multiple sclerosis or Parkinson's disease [18][19][20][21][22] . A decrease in RNFL thickness or volume evaluated by OCT thereby represents an indicator of atrophy due to axonal and neuronal loss and multiple studies have shown that these alterations can be detected even earlier than through funduscopy 17,23 . Therefore, OCT allows a reliable estimation of axonal integrity of the anterior visual pathway 3,23,24 .In patients with ESRD, alterations like lenticular opacities, changes in choroidal and central corneal thickness, retinal layer thickness as well as intraocular pressure can be observed...

Retinal Neurovascular Impairment in Non-diabetic and Non-dialytic Chronic Kidney Disease Patients

“…On the other hand, significantly decreased RNFLt was observed in CKD patients according to previous studies ( Demir et al, 2009 ; Jung et al, 2020 ; Wu et al, 2020 ). However, our study failed to detect significantly decreased RNFLt in either the CKD 1–2 group or the CKD 3–5 group compared to the control group.…”

“…However, the definition of CKD applied in the aforementioned studies was based on an eGFR of <60 ml/min/1.73 m 2 (CKD stages 3-5) and failed to include earlier stages CKD patients with an eGFR of > 60 ml/min/1.73 m 2 (namely, CKD stages 1-2) using parameters such as proteinuria or UACR to detect early renal damage and declining renal function. Our study evaluated retinal neural parameters in non-diabetic CKD patients of stages 1-2 (versus health subjects) and revealed that retinal neuronal impairment, which might even precede microvascular rarefaction and retinal axon damage, could be detected in earlier CKD stages than those reported in prior studies (Jung et al, 2020;Wu et al, 2020).…”

“…However, our study failed to detect significantly decreased RNFLt in either the CKD 1–2 group or the CKD 3–5 group compared to the control group. Two possible reasons may suffice to explain this conflicting result: firstly, significant reduced RNFLt were detected in end-stage renal disease patients which have been treated with dialysis in previous studies ( Demir et al, 2009 ; Jung et al, 2020 ). But in our study, patients undergoing dialysis were excluded because dialysis itself might exert a significant impact on the neurovascular system.…”

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

“…Although retinal neurodegeneration has been reported in prior studies [4][5][6], it is unclear to what extent it might cause visual acuity decline in CKD patients. Ganglion cell complex (GCC) thickness on spectral domain optical coherence tomography (OCT) is a sensitive biomarker for retinal ganglion cells (RGCs) loss and can be used as an indicator of the retinal neurodegeneration [7][8][9][10][11].…”

“…Patients with CKD could have increased risk of visual impairment by three-to seven-fold [2,3]. The causes of the visual decline may be attributed to either definite ocular diseases, such as cataract, glaucoma, age-related macular degeneration (AMD), diabetic retinopathy (DR), and other retinopathies [2,3], or non-specific ocular pathologies such as retinal microvascular degeneration and retinal neurodegeneration [4][5][6].…”