Retinal Changes in Chronic Kidney Disease: A Spectral-Domain Optical Coherence Tomography Study Correlated with...

Chronic Kidney Disease (CKD) is a significant public health problem associated with considerable morbidity and mortality. It is known to cause retinal vascular changes and retinopathy that reflects changes occurring in the kidneys. Optical coherence tomography (OCT) is a promising biomarker for assessing retinal changes associated with CKD. This study was conducted to evaluate retinal alterations in patients with CKD using spectral-domain optical coherence tomography (SD-OCT), correlate these findings with biochemical parameters to facilitate early screening and timely detection, and assess disease progression.

This single-centre, cross-sectional study included 60 eyes of 60 patients with stage 3, 4, or 5 CKD. Data collected included age, sex, glycaemic status, serum electrolytes, blood urea nitrogen (BUN), and serum creatinine. Fundus examination and various OCT parameters were measured. Central retinal thickness (CRT) and central choroidal thickness (CCT) were measured manually at the subfoveal region. Automated segmentation was used to measure retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) thicknesses across all quadrants and sectors using SD-OCT. Descriptive and inferential statistical analyses were applied to assess significance.

Most patients were in Stage 3 CKD, with the majority having a disease duration of 1-3 years. Mean retinal thickness reduced from stage 3 to 5 with no statistical significance, while choroidal thickness remained preserved. Inferior RNFL thickness declined significantly with worsening CKD, whereas temporal RNFL and GCC showed borderline significance. Retinal parameters did not differ by CKD duration. Elevated HbA1c was associated with increased retinal thickness and thicker inferior RNFL. Both hypernatremia and hyperkalemia were associated with reduced retinal thickness. A higher glomerular filtration rate (GFR) was positively correlated with inferior RNFL thickness.

The findings of this study suggest that chronic kidney disease is associated with progressive neuroretinal changes, particularly thinning of the inferior retinal nerve fibre layer, which may reflect underlying microvascular and neurodegenerative processes occurring in CKD. The preservation of choroidal thickness despite declining renal function indicates that neuroretinal alterations may precede detectable choroidal changes. The observed associations between OCT parameters and biochemical markers, including HbA1c, serum sodium, potassium, and GFR, further support the influence of systemic metabolic and renal status on retinal structure.

The study highlights that chronic kidney disease is associated with neuroretinal alterations that become more pronounced as disease severity increases. Optical Coherence Tomography has emerged as an important biomarker for evaluating these retinal changes. Further, by correlating OCT findings with biochemical parameters, we can evaluate the impact of systemic parameters in CKD on the retina. Therefore, OCT is an important tool in CKD that helps with screening, monitoring, and assessing disease progression.