Endocrine Abstracts

Introduction: Cataract development as a complication of diabetes is usually associated with increased age and longer duration of diabetes. However, rapidly progressive cataracts have also been described at, or soon after, diagnosis of type 1 diabetes (T1DM). We report two cases of adolescents with T1DM and bilateral cataracts, including one case in which visual loss was the presenting symptom.

Cases: A 16-year old non-obese, caucasian boy presented to his GP with acute bilateral visual loss. He described increasingly blurred vision in his left eye for three weeks and had noticed similarly blurred vision in his right eye that morning. He also reported tiredness and new-onset nocturia for approximately a month, although he denied polydipsia or weight loss. Blood glucose was 26 mmol/l and ketones were 2.6 mmol/l, leading to a diagnosis of T1DM. His HbA1c was 149 mmol/mol at diagnosis. Ophthalmologic examination demonstrated bilateral dense posterior subcapsular cataracts; the left cataract was visible with the naked eye. He underwent sequential bilateral cataract removal within two weeks of diagnosis due to severely impaired vision, with good outcome. A 13-year old non-obese, caucasian girl had a one-year history of T1DM, treated with a basal bolus insulin regimen. She saw her community optician due to visual glare and was referred to the ophthalmology clinic where she was diagnosed with bilateral early cataracts. Her symptoms progressed quickly, and within a month her vision had significantly worsened . She underwent sequential bilateral cataract removal which restored her vision to normal.

Discussion and learning points: Cataracts in early type 1 diabetes are rare, with an incidence of less than 1%. The pathogenesis of cataracts in diabetes is not fully understood; likely mechanisms include osmotic stress from sorbitol accumulation in the lens, oxidative stress, and glycation of lens proteins. Previous literature suggests that early diabetic cataracts are more common in adolescent females. Another postulated risk factor is a prolonged period of hyperglycaemia, such as prior to diagnosis in our first case. Our cases reinforce the need to conduct ocular screening from diagnosis of diabetes, and to consider diabetes in any young person presenting with cataracts.