Chronic kidney disease (CKD) is a progressive and irreversible condition characterized by a gradual decline in renal function, typically staged according to glomerular filtration rate (GFR). Affecting over 10% of the global population, CKD is a major contributor to morbidity and mortality worldwide (1). Although the renal system is primarily affected, CKD exerts systemic effects that extend beyond the kidneys, involving the cardiovascular, neurological, skeletal, and ocular systems (2).

The eye, often referred to as the window to systemic disease, mirrors many underlying metabolic and vascular disturbances seen in chronic illnesses, including CKD. The retina and kidneys share similar anatomical and physiological features, including a rich microvascular network, autoregulated blood flow, and susceptibility to endothelial damage (3). This concept underlies the “renal-retinal axis,” suggesting a pathophysiological connection between declining kidney function and retinal or ocular abnormalities (4).

Ocular manifestations in CKD are both common and diverse. They range from retinal microvascular changes (such as hypertensive and diabetic retinopathy) to optic nerve alterations, conjunctival pallor, dry eye disease, and even corneal calcifications and cataracts, particularly in patients on long-term dialysis (5). The presence and severity of these ocular changes often correlate with the stage of CKD, systemic comorbidities such as hypertension and diabetes, and the duration of renal impairment (6).

Recent studies have reinforced the hypothesis that retinal microvascular signs can serve as early indicators of systemic vascular dysfunction, including renal damage. In fact, fundoscopic examination and advanced retinal imaging techniques like optical coherence tomography (OCT) and OCT-angiography (OCTA) are increasingly being used to non-invasively assess vascular health in CKD patients (7). For instance, narrowing of the retinal arterioles, vascular tortuosity, and arteriovenous nicking have been significantly associated with reduced eGFR and albuminuria (8).

Furthermore, ocular complications of CKD may precede overt nephrological symptoms, making ophthalmological evaluation a potentially valuable tool in early detection and risk stratification of renal disease (9). Understanding this relationship is crucial not only for preserving visual function but also for holistic patient care in nephrology and internal medicine.

Despite this important overlap, ophthalmic assessment is often overlooked in routine CKD management, and many ocular conditions remain undiagnosed until they significantly impair vision. Therefore, this study aims to evaluate and correlate the spectrum of ocular manifestations across different stages of CKD, helping to highlight the importance of early ophthalmic screening in renal disease progression (10).

This hospital-based, cross-sectional observational study was conducted over a period of six months in the departments of nephrology and ophthalmology at a tertiary care centre. A total of 80 adult patients diagnosed with chronic kidney disease (CKD), irrespective of the stage, were included after obtaining informed written consent. The staging of CKD was done in accordance with the KDIGO (kidney disease: Improving Global Outcomes) guidelines based on estimated glomerular filtration rate (eGFR).

Patients aged 18 years or older with a confirmed diagnosis of CKD, including those on dialysis and those not requiring dialysis, were eligible to participate. Individuals with a history of ocular trauma, previous intraocular surgery, or pre-existing primary ocular diseases unrelated to CKD were excluded. Patients diagnosed with acute kidney injury or diabetic retinopathy without coexisting CKD were also excluded from the study.

Participants were selected using simple random sampling from the nephrology inpatient and outpatient registers. Detailed clinical information was collected, including age, sex, CKD stage, etiology and duration of kidney disease, presence of hypertension or diabetes mellitus, and current treatment status including dialysis.

Each participant underwent a comprehensive ophthalmological evaluation conducted by a single experienced ophthalmologist to ensure consistency. The assessment included best corrected visual acuity (BCVA), slit lamp biomicroscopy for anterior segment evaluation, fundus examination by both direct and indirect ophthalmoscopy, and intraocular pressure measurement using Goldmann applanation tonometry. Where indicated, optical coherence tomography (OCT) and fundus photography were performed to support diagnosis and documentation of retinal or optic nerve abnormalities.

All ocular findings were recorded systematically and correlated with the CKD stage. The data were compiled and analyzed statistically using SPSS software, with descriptive statistics used for demographic data and the Chi-square test employed to determine associations between ocular findings and CKD stages. A p-value less than 0.05 was considered statistically significant.

Table 1 presents the gender distribution of the study population. Out of 80 participants, 44 were males (55.0%) and 36 were females (45.0%), indicating a slight male predominance in the study sample.

Table 2 shows the alcohol consumption history among the participants. Of the total, 22 individuals (27.5%) reported a history of alcohol consumption, while 58 (72.5%) did not consume alcohol. This highlights that a significant proportion of CKD patients were non-alcoholic.

Table 3 details the tobacco chewing history in the study population. A total of 31 participants (38.8%) had a history of tobacco chewing, whereas 49 (61.2%) had no such habit. This suggests that tobacco usage was relatively common among the CKD group, potentially contributing to systemic and ocular complications.

Table 4 illustrates the correlation between CKD stage and visual status. It was observed that visual impairment and blindness increased progressively with advancing stages of CKD. In Stage 1, most patients had good vision, whereas in Stage 5, a majority were visually impaired or blind. Specifically, blindness (<6/60) was observed in 15 patients, with the highest concentration in Stage 5. These findings support the hypothesis of worsening ocular outcomes as renal function declines.

Table 5 summarizes the eyelid manifestations observed among the participants. Normal eyelids were noted in 90% of patients. Pathological findings included sebaceous cysts in 3.8%, xanthelasma in 2.5%, papillomas in 2.5%, and nevi in 1.2%. Although less frequent, these findings indicate possible lipid metabolism disorders and local dermatologic changes associated with CKD.

Table 6 presents the conjunctival manifestations. Most patients (87.5%) had normal conjunctiva. Nasal pterygium was seen in 5.0% of cases, while biheaded pterygium and pinguecula were present in 3.8% each. These conditions are often related to chronic irritation and may be aggravated by systemic conditions such as CKD.

Table 7 shows the lens findings based on slit lamp examination. Immature cataract was the most common abnormality, seen in 62.5% of participants. Pseudophakia, indicating previous cataract surgery, was present in 37.5% of cases. This high cataract prevalence may reflect the oxidative stress and electrolyte disturbances commonly seen in CKD.

Table 8 displays the fundoscopy results. Normal fundus findings were seen in 39 patients (48.8%), while 41 patients (51.2%) had abnormal findings. The high rate of abnormal fundoscopic changes underscores the vascular and structural impact of CKD on the retina, emphasizing the need for regular ophthalmic screening in this population.

Table 1: Gender Distribution of the Participants

Table 2: Alcohol Consumption History

Table 3: Tobacco Chewing History

Table 4: Visual Status According to CKD Stage

Table 5: Eyelid Manifestations

Table 6: Conjunctival Manifestations

Table 7: Lens Evaluation Findings

Table 8: Fundoscopy Results

The findings of this study reinforce the presence of a significant and progressive association between the severity of chronic kidney disease (CKD) and various ocular manifestations. As CKD advances, there is a marked deterioration in visual acuity, with higher stages of CKD correlating strongly with increased prevalence of visual impairment and blindness. This pattern reflects the shared microvascular pathology that exists between the renal and retinal circulatory systems.

In the present study, only 13 patients were in Stage 1 of CKD, and the majority (77%) of them retained good vision. However, as the CKD stage increased, the proportion of patients with visual impairment or blindness rose sharply, peaking in Stage 5, where 100% of patients had compromised vision. These findings align closely with the work of Rathi et al. (2022), who emphasized that retinal microvascular alterations, including narrowing of arterioles and vascular tortuosity, become more pronounced with worsening kidney function, suggesting a parallel decline in microvascular health in both organs (11).

Ocular surface manifestations were also notable in our cohort. Eyelid lesions such as sebaceous cysts, xanthelasma, and papillomas were detected in 10% of cases. Though not life-threatening, these findings may reflect altered lipid metabolism and chronic inflammation associated with CKD. According to Sharma et al. (2021), xanthelasma and other lid abnormalities are often early cutaneous signs of dyslipidemia in CKD patients and may serve as indicators of systemic disease progression (12).

Similarly, conjunctival lesions including pterygium and pinguecula were observed in a small but significant number of patients, likely reflecting chronic irritative and degenerative changes, possibly exacerbated by anemia, uremic toxins, and systemic oxidative stress. A study by Lin et al. (2023) reported that conjunctival degenerative changes were more prevalent in patients undergoing dialysis and correlated with hemoglobin levels and duration of renal disease (13).

One of the most striking findings was the high prevalence of lens opacities, with 62.5% of patients presenting with immature cataracts and an additional 37.5% having undergone cataract surgery (pseudophakia). These findings support the role of electrolyte imbalance, calcium-phosphorus dysregulation, and uremic toxin accumulation in promoting lenticular changes. This mirrors the conclusions drawn by Alhassan et al. (2020), who found significantly increased rates of early cataract development among CKD patients, especially those with secondary hyperparathyroidism (14).

Furthermore, fundoscopy revealed that more than half of the patients (51.2%) had abnormal retinal findings. Although specific diagnoses were not classified in the current data, this aligns with previous work showing that CKD is frequently associated with hypertensive and ischemic retinopathies, as well as optic nerve changes due to chronic anemia and fluid overload. Most recently, Patel et al. (2024) demonstrated that abnormal fundus findings can precede overt decline in eGFR and proposed integrating ophthalmic screening as part of regular CKD management (15).

Taken together, these results highlight the renal-retinal connection as more than just theoretical. They provide real-world evidence that visual health deteriorates in a predictable manner with the progression of kidney disease. Regular ophthalmological examination can thus serve not only to preserve vision but also to monitor systemic microvascular health and guide nephrological interventions.

This study demonstrated that ocular manifestations are common in patients with chronic kidney disease and increase in frequency and severity with advancing CKD stages. Visual impairment and blindness were found to be particularly prevalent in patients with Stage 4 and Stage 5 CKD. In addition to refractive and visual changes, significant eyelid, conjunctival, lens, and fundoscopic abnormalities were observed. These findings emphasize the importance of regular ophthalmic screening as an essential part of CKD evaluation and management. Early detection and timely referral to ophthalmology may prevent irreversible vision loss and also provide insights into the systemic progression of renal dysfunction.

1. Hill NR, Fatoba ST, Oke JL, Hirst JA, O'Callaghan CA, Lasserson DS, et al. Global prevalence of chronic kidney disease – a systematic review and meta-analysis. PLoS One. 2021;16(7):e0254529.
2. Chen TK, Knicely DH, Grams ME. Chronic kidney disease diagnosis and management: A review. JAMA. 2019;322(13):1294–304.
3. Nguyen TT, Wang JJ, Wong TY. Retinal vascular changes in pre-diabetes and prehypertension: New findings and their research and clinical implications. Diabetes Care. 2020;43(2):305–13.
4. Wong TY, Mitchell P. The eye in hypertension. Lancet. 2019;389(10085):1264–74.
5. Sahin M, Sahin A, Ozkurt ZG, et al. Ocular findings in hemodialysis and peritoneal dialysis patients: A comparative study. Ren Fail. 2022;44(1):123–9.
6. Singhal A, Gaur N, Gupta S, et al. Ocular manifestations in chronic kidney disease: A cross-sectional study. Indian J Nephrol. 2023;33(1):33–9.
7. Lim LS, Cheung CY, Mitchell P, Wong TY. Retinal vascular imaging in systemic diseases. Prog Retin Eye Res. 2020;82:100898.
8. Kawasaki R, Xie J, Cheung N, et al. Retinal arteriolar narrowing and chronic kidney disease progression: A prospective cohort study. Kidney Int. 2021;99(5):1140–7.
9. Kalra OP, Jha V. Renal and retinal interplay: Emerging perspectives. Nat Rev Nephrol. 2023;19(2):67–76.
10. Rajalakshmi R, Sahoo J, Jain S, et al. Retinal imaging as a potential screening tool for kidney disease. BMJ Open Ophthalmol. 2024;9(1):e001256.
11. Rathi N, Kumar S, Tiwari R. Retinal microvascular abnormalities in non-diabetic chronic kidney disease patients. Kidney Res Clin Pract. 2022;41(1):58–64.
12. Sharma A, Verma M, Joshi H. Cutaneous and ocular signs as indicators of lipid abnormalities in CKD. Int J Dermatol Ophthalmol. 2021;10(2):81–86.
13. Lin YC, Lin HY, Hsu KH. Ocular surface changes in patients with end-stage renal disease on hemodialysis: A cross-sectional study. BMC Ophthalmol. 2023;23(1):87.
14. Alhassan MB, Isyaku M, Balarabe AH. Lens opacity among patients with chronic kidney disease: Correlation with serum calcium-phosphorus product. Saudi J Ophthalmol. 2020;34(3):181–186.
15. Patel V, George J, Sharma R. Retinal changes as a predictor of renal deterioration: A nephro-ophthalmic interface. Clin Ophthalmol. 2024;18:227–233.