Cataract: refractive error, diabetes, and morphology.

A retrospective analysis of 388 records of patients undergoing surgery for cataract between the years 1968 and 1978 showed that more women than men were admitted. About 13.7% of the patients were diabetic, and there was a striking excess of women over men with diabetes and cataract. The diabetic patients required surgery at an earlier age than the non-diabetics. Patients who had been refracted at least 5 years before surgery showed an incidence of myopia of -1.00 D or more of 25.4%. In 34% of the whole series the aphakic refraction was less than +11.00 D, again suggesting that myopes are more likely to develop a cataract than non-myopes. Posterior subcapsular lens changes alone or in combination with nuclear or cortical opacities were present in over 40% of all patients and the mean age of patients with this type of change alone was significantly lower than patients with predominantly nuclear or cortical changes. Posterior subcapsular opacities seem to be more common in Iowa than in England or India. The morphological similarity of this type of lens change with known types of secondary cataract suggests that it is not entirely a senile change but may be due to environmental or dietetic factors.