Vitamin C and the Lens: New Insights into Delaying the Onset of Cataract

Abstract

Cataracts or clouding of the lens is the leading cause of blindness in the world. Age and diabetes are major risk factors, and with an increasing aging and diabetic population, the burden of cataracts will grow. Cataract surgery is an effective way to restore vision; however, alternatives to cataract surgery are required to reduce the looming cataract epidemic. Since it is well established that oxidative damage plays a major role in the etiology of cataracts, antioxidants have been promoted as therapies to delay and/or prevent cataracts. However, many antioxidant interventions including vitamin C have produced mixed results as anti-cataract therapies. Progress has been made towards our understanding of lens physiology and the mechanisms involved in the delivery and uptake of antioxidants to the lens which may guide future studies aimed at addressing some of the inconsistencies seen in previous animal and human studies. Of interest is the potential for vitamin C based supplements in delaying the onset of cataracts post vitrectomy which occurs in up to 80% of patients within two years. These targeted approaches are required to reduce the burden of cataract on hospitals and improve the quality of life of our aging and diabetic population.

Signature of Circulating Biomarkers in Recurrent Non-Infectious Anterior Uveitis. Immunomodulatory Effects of DHA-Triglyceride. A Pilot Study

“…However, there is a lack of consensus among ophthalmologists and researchers on the interest of nutritional supplements containing antioxidant vitamins, carotenoids, trace elements and/or ω3 PUFAs in ophthalmology. Dry eye disease [ 14 , 15 , 16 ], myopia complications and progression [ 72 ], cataracts [ 32 , 73 ], or sight-threatening diseases such as glaucoma, DR, and AMD [ 16 , 17 , 18 , 19 , 20 , 21 , 32 , 74 , 75 , 76 , 77 , 78 , 79 ], have been important targets of antioxidants and ω3 PUFAs. DHA is an essential structural constituent of cell membranes.…”

Proteome Remodeling of the Eye Lens at 50 Years Identified with Data-Independent Acquisition

“…Previous lens proteome studies have identified putative transporters of GSH and its precursors, but not in the human lens (8,10,59). GSH uptake from extracellular suture space is putatively mediated by organic anion transporter 3 (OAT3) and sodium-dependent dicarboxylate transporter 3 (NaDC3) and efflux is mediated by multidrug resistance proteins 4 and 5 (MRP4/5) and connexins 46 and 50 (GJA3/8), which can transport molecules up to approximately 1 kDa through gap junction channels (15).…”

The Postvitrectomy Cataract

“…20 In contrast, results of daily supplementation with 500 mg oral vitamin C did not prevent age-related cataract changes-although mechanistically, postvitrectomy eyes may be predicted to demonstrate a greater effect, no formal controlled studies have been completed in this specific patient population to date. 21 Other methods to reduce postvitrectomy cataracts include a novel irrigation solution containing benzopyranyl esters and amides, which in a rabbit animal model prevented abnormal postvitrectomy posterior lens fiber changes. 22 Last, maintaining "face-down" positioning to reduce direct contact of the gas and the lens postsurgery has been shown to reduce postvitrectomy cataract formation after gas tamponade.…”