Visual function and morphological changes in the macular area of patients with type 2 diabetes mellitus after intensive insulin therapy

Background Intensive insulin therapy has been found to lessen the progress of diabetic retinopathy (DR) to some extent, while it has also been implicated to be responsible for decrease of DR. We investigated visual function and morphological changes in the macular area in short-term follow-up of patients with type 2 diabetes mellitus after intensive insulin therapy.

Methods This was a prospective clinical study of nonproliferative DR patients (102 eyes, 120 patients) undergoing intensive insulin therapy. The Contrast Glare Tester (Takagi CGT-1000) was used to examine contrast sensitivity (CS) and Heidelberg Retina Tomograph (HRT) II and Stratus Model 3000 OCT were used to observe the changes of morphology in the macular area. Follow-up times were pre-intensive therapy, 3 and 6 months post-intensive therapy.

Results CS at low and middle frequencies was higher at 3 and 6 months post-therapy compared with pre-therapy (P <0.05). Significant differences in CS at low frequency were found between 6 and 3 months post-therapy (P <0.05). Macular edema index was lower in the first, second, and third rings of the macular area after intensive therapy compared with pre-therapy (P <0.05). Compared with 3 months post-therapy, the macular edema index was lower in the first, second, and third rings of the macular area at 6 months post-therapy (P >0.05). No significant differences in the thickness of the first, second, and third rings of the macular area were detected between 3 and 6 months post-therapy and pre-therapy (P >0.05).

Conclusion CS and macular edema indexes were significantly improved in nonproliferative diabetic retinopathy patients after intensive insulin therapy, but thickness of the macular area was unchanged.