December 28, 2007
Question from Adealide, South Ausrtalia:
What can you tell me about sugar cataracts? My daughter's vision has been blurry. We mentioned this to her specialist who said this was nothing to do with diabetes as she has only been diagnosed for eight months, but we visited an optometrist who said she had diabetic cataracts. She has reasonable A1c results, but has had many highs and lows in the last year. Can these develop so quickly? We are investigating her vision further, but want some idea of why in the meantime.
Vision fluctuation is extremely common in patients with poor blood glucose control, due to variable absorption of glucose, which is then converted to sorbitol, within the eye’s internal lens. This process can occur over a matter of a few hours. Sorbitol accumulation within the lens leads to an osmotic gradient that draws in fluid and changes the patient’s prescription; if this process goes on long enough, cataract formation occurs. In the early stages, the lens appears swollen when examined by the eye doctor at the slit lamp (a type of microscope specifically designed for looking at the eye), and this swollen appearance is referred to as “lenticular intumescence” or “early diabetic cataract.” At this early stage, the process is reversible if blood sugar control improves. If the precise arrangement of collagen fibers within the lens is disrupted for more than a few weeks, however, permanent opacity (cataract) results.