Iris neovascular tufts. Relationship to rubeosis, insulin, and hypotony.

Iris neovascular tufts are abnormal proliferations of twisted microcapillary loops that project from the iris pupillary border. They appear to be a morphologic variant of rubeosis iridis. This study searched for iris neovascular tufts by biomicroscopy and iris fluorescein angiography. They were found in two of 16 (12.5%) myotonic dystrophy patients, in two of 30 (6.7%) maturity-onset diabetics, and in zero of 14 (0%) juvenile-onset diabetics. Myotonic and adult-onset diabetics have in common pancreatic beta-cell dysfunction, abnormally high serum insulin levels, and possibly defective hormone-receptor interactions. Whether these factors contribute to the altered blood-iris barrier and iris neovascular tufts in these groups is uncertain, but a correlation is suggested because the myotonic with the highest insulin level also had the most prominent tufts. Hyperinsulinemia and ocular hypotony are associated with neovascular tufts.