Chronic Kidney Disease and Cataract: Seeing the Light

lence of cataracts in CKD, and, for the first time, suggests that cataracts become more common as renal failure worsens. The relationship between CKD and cataract has long been suspected, but it was only recently that it was only recently confirmed. The study by Liu et al. [3] is a retrospective analysis of data from a public health system; the authors included only individuals who had accessed cataract surgery. Overall, patients with CKD had a 1.84 increased risk (95% CI 1.73–1.95) of cataract after correcting for age, gender, hypertension, socioeconomic status, smoking, and other comorbidities. The risk was even higher for those with end-stage renal failure (2.33, 95% CI 2.10–2.59), suggesting that CKD itself contributed to cataracts. However, this study did not conclude whether CKD was important in cataract initiation or progression. Cataract is the clouding of the lens that reduces vision and produces glare and, less often, monocular diplopia. Worldwide, cataract is the commonest cause of blindness. In the US, 17.2% of adults over the age of 40 years have at least one cataract, and a further 5.1% have already had corrective surgery [4] . Cataracts impair the quality of life, contribute to depression, with an effect comparable to a major medical condition such as stroke [5] , and increase morbidity and mortality, through more frequent falls and hip fractures. Chronic kidney disease (CKD) affects more than 10% of the world’s adult population, and its prevalence increases with age. Visual impairment is common in CKD, and results from the increased likelihood of cataract, glaucoma, microvascular and diabetic retinopathy, and age-related macular degeneration [1] . Hypertension and diabetes are the most common renal diseases with ocular complications. In addition, many inherited forms of renal diseases have ocular features. This is because the kidney and the eye are structurally similar with glomerular/retinal epithelial cells overlying a basement membrane of collagen IV α3α4α5 and capillary network [1, 2] , and the kidney and eye sharing developmental processes that are dependent on the same transcription factors [2] . Inherited diseases with ocular manifestations include Alport syndrome, dense deposit disease, tuberous sclerosis, cystinosis, Fabry disease, nephronophthisis, and renal-coloboma syndrome [2] . In addition, some treatments for renal disease have ocular complications, such as steroid-induced cataract and hydroxychloroquine-associated maculopathy. Renal failure itself results in the ocular features of scleral calcification, and cataracts. The paper by Liu et al. [3] in this issue of American Journal of Nephrology highlights the increased prevaPublished online: May 20, 2017 Nephrology American Journal of