Ischemic diabetic retinopathy may protect against nuclear sclerotic cataract

Abstract

Purpose: To determine whether diabetes mellitus is protective for nuclear sclerotic cataract at baseline and 6 and 12 months after vitrectomy surgery.

Design: Prospective, interventional cohort study.

Methods: Phakic diabetic and nondiabetic patients undergoing vitrectomy surgery for a variety of retinal conditions underwent Scheimpflug lens photography in the operated and fellow eye at baseline and at 6 and 12 months after vitrectomy surgery.

Results: Of 52 eyes included in the analysis, 23 eyes were from diabetic patients, 14 of which had surgery for ischemic retinopathy. At baseline, eyes with ischemic diabetic retinopathy had less nuclear sclerotic cataract than nonischemic diabetic and nondiabetic eyes. This was true for eyes undergoing vitrectomy surgery (P = .0001) and for fellow eyes (P = .003). Nuclear sclerotic cataract developed after vitrectomy surgery in nonischemic diabetic eyes and nondiabetic eyes at the same rate. Diabetic eyes with ischemic retinopathy showed no significant progression of nuclear opacification, and therefore had significantly less postvitrectomy nuclear cataract at 6 months (P < 1 × 10(-6)) and at 12 months (P < .001) than nondiabetic or nonischemic diabetic eyes. Normalizing to baseline opacity and adjusting for age and other comorbidities did not alter this result.

Conclusions: Ischemic diabetic retinopathy, not just systemic diabetes mellitus, protected against nuclear sclerotic cataract at baseline and after vitrectomy surgery. These findings are consistent with the hypothesis that increased exposure to oxygen is responsible for nuclear cataract formation.

Figure 1

A Scheimpflug image showing the location at which nuclear opacity was measured. CCL: central cortical line; CNL: central nuclear line; A: Peak of light scattering at the anterior border of the adult nucleus; B: Central clear zone. EAS analysis method: the software automatically sets up the central line on the slit image; point “0” is the anterior lens capsule. Points 1 and 2 are manually selected using the intensity plot. The average light scattering intensity per pixel along CNL was used to quantify lens nuclear changes.

Figure 2

The percentage of patients having cataract surgery at 6 and 12 months after vitrectomy. The solid line represents non-ischemic patients and the dotted line patients with ischemic diabetic retinopathy.

Figure 3

Scheimpflug lens photos showing typical changes in nuclear opacity before and after vitrectomy in non-ischemic eyes and eyes with ischemic diabetic retinopathy. The upper group of images is from the eyes of a non-diabetic patient, age 51. The lower group of images is from a diabetic patient with ischemic retinopathy, age 56. Left images are baseline photos taken before vitrectomy. Right images were photos taken 12 months after vitrectomy. Pink areas indicate the light scattering intensity along the anterior half of the central line.

Figure 4

Results of Scheimpflug photography: Average nuclear opacity measured in pixel intensity in the ischemic DM and non-ischemic (diabetic and non-diabetic) eyes at baseline and at 6 and 12 months after vitrectomy.

Figure 5

The graph depicts the change in nuclear opacity from baseline to 6 and 12 months. To eliminate the differences in NS cataract at baseline and to represent the amount of change in the lens, all lens values at the baseline were set to 1.0.