Medical supervision of patients with chronic kidney disease and end-stage renal disease (ESRD) seldom requires specific attention to the eyes. An important exception is the need for perpetual surveillance, in collaboration with an ophthalmologist, of all dialysis patients with diabetes, in whom the risk of vision loss is substantial.
Disorders of the kidney rarely directly affect vision or change the anatomic integrity of the eyes. Recognition of a coincident eye problem during evaluation of kidney disease is usually fortuitous. As an example, advanced proliferative diabetic retinopathy can be completely asymptomatic. At the other extreme, complaints about vision may lead to the diagnosis of a previously unsuspected kidney disease. The presence of Alport syndrome, for example, may be detected when corneal erosion or anterior lenticonus is found during the assessment for blurred vision.
OPHTHALMOSCOPIC EVALUATION AND GENERAL FINDINGS IN CHRONIC KIDNEY DISEASE AND END-STAGE RENAL DISEASE
A comprehensive study of a patient with chronic kidney disease (CKD) or end-stage kidney disease (ESRD) should include examination of the external eye and direct ophthalmoscopy. Benefits of this approach were noted in a multicenter, cross-sectional longitudinal study of 1936 individuals with varying stages of CKD in which 45 degree digital photos of the disc and macula in both eyes, obtained by nonophthalmologic personnel, were assessed in a masked manner by a retinal specialist . A total of 1904 subjects (98 percent) had satisfactory photographs of at least one eye, of whom eye “pathologies” requiring follow-up examination by an ophthalmologist were identified in 864 (45 percent). These pathologies included serious eye conditions requiring urgent treatment in 65 participants (3 percent) and diabetic and/or hypertensive disease in 482 (25 percent). An estimated glomerular filtration rate (GFR) less than 30 mL/min per 1.73 m2 was associated with a three times higher risk for retinopathy than a normal GFR.
Advanced kidney disease of any etiology induces eye findings that signal the need for initiation or intensification of therapy. As examples:
- Conjunctival erythema, termed the red eyes of uremia, may be noted when high plasma phosphate levels induce corneal and conjunctival precipitation of calcium pyrophosphate.
- Metastatic calcification in the eyes may be associated with elevations of the serum concentration of calcium or calcium-phosphate product .
- Profound uremia may rarely be complicated by transient cortical blindness; this is termed uremic amaurosis, which occurs in association with preserved pupillary contraction on light exposure and normal fundoscopic findings. This abnormality clears within 24 to 48 hours of initiating dialytic therapy . Evanescent cortical blindness has also been reported in kidney transplant recipients treated with cyclosporine and interferon [4,5].