Changes in the internal structure of the human crystalline lens with diabetes mellitus type 1 and type 2.

Purpose: To investigate the effect of diabetes mellitus (DM) type 1 and type 2 on the internal structure of the lens.

Design: Observational cross-sectional study.

Participants And Controls: One hundred seven patients with DM type 1, 106 patients with DM type 2, and 75 healthy control subjects.

Methods: Scheimpflug photography was used to image the lens of the right eye of 213 patients with DM and 75 healthy control subjects. The densitogram of the Scheimpflug image was used to indicate the nucleus and the different layers of the cortex of the lens. Lenses with cataract were excluded.

Main Outcome Measures: The size of the nucleus and the different layers of the cortex of the lens.

Results: The nucleus and the different cortical layers of the DM type 1 lenses were significantly thicker compared with those of the control group (P<0.001). A significant association was found between the duration of DM type 1 and both the anterior and posterior cortex, its different layers, and the nucleus (P<0.001). The increase in the anterior and posterior cortex with the duration of DM was comparable with that of the nucleus. No important differences in the internal structure of the lens were found between the patients with DM type 2 and the control group.

Conclusions: Diabetes mellitus type 1 has a significant effect on the internal structure of the lens. The difference in effect of DM type 1 and type 2 on internal lens structure suggests an essential difference in pathogenesis. Furthermore, the results of the present study may indicate that the increase in the size of the lens with DM type 1 is the result of a generalized swelling of the lens, affecting all its different parts.