Posttransplant cataract: lessons from kidney-pancreas transplantation

Cataract is a major cause of visual disturbance after transplantation. Although corticosteroid therapy has been linked with posterior subcapsular cataract, its natural history in the cyclosporine era is not well understood.

Baseline and regular postoperative slit-lamp biomicroscopy and ophthalmic examinations (n=432) were performed in 108 eyes of simultaneous kidney/pancreas (SPK) recipients (n=54) for up to 10 years after transplantation. Triple therapy immunosuppression of cyclosporine, azathioprine, and prednisolone was used.

Cataract was present in 40% of eyes at simultaneous kidney/pancreas associated with duration of diabetes, lower insulin dose, and the use of pretransplant hemodialysis (P<0.05-0.01). Cataract became increasing more common 2 years after simultaneous kidney/pancreas, and lens abnormalities were virtually universal at 6-10 years by slit lamp biomicrosopy. The instantaneous hazard rate for new cataract formation was highest within the first 2 years and remained abnormal for the study duration. Nuclear and posterior subcapsular cataract increased significantly after transplantation (P<0.05) and were the predominant types of cataract presenting late. Risk factors for posttransplant cataract formation included older age and high-dose pulse methylprednisolone dose. Visual acuity was reduced by severity of cataract grade, presence of combined nuclear and subcapsular cataract, retinal hemorrhage and underlying diabetic retinopathy (P<0.05-0.001). Cataract formation imposed significant additional impairment of visual acuity above that of diabetic retinopathy. Cataract surgery was undertaken in 14% of eyes, improving visual acuity from mean decimalized score of 0.28 to 0.43, P<0.01 but did not normalize it to the noncataract level of 0.72.

Transplantation substantially increases all types of cataract, and is highly prevalent by slit lamp examination. High-risk patients are older and diabetic, and received hemodialysis and pulse corticosteroid therapy. In contrast to older studies using high-dose corticosteroid and azathioprine, the pattern of cataract in the cyclosporine era is different with broader cataract types, a weaker association with corticosteroids and a progressive course. Regular screening of visual acuity and appropriate surgery for posterior subcapsular or severe cataract are recommended.