AIM: To investigate the operation timing of cataract surgery for severe non-proliferative diabetic retinopathy(NPDR).

METHODS:Totally 120 eyes with severe NPDR were divided into 3 groups according to the timing of cataract surgery. Group A never treated with panretinal photocoagulation, and focal or grid macular laser. Group B was treated with panretinal photocoagulation and focal or grid macular laser for less than 3 months. Group C was treated with panretinal photocoagulation and focal or grid macular laser for more than 6 months. We examined the changes of macular thickness using OCT before cataract surgery and 1 month and 6-months after surgery. The central subfield mean thickness(CSMT)was used to evaluate macular edema which was defined as an increase of CSMT(ΔCSMT)> 30% from the baseline. We also analyzed the best-corrected visual acuity of the three groups.

RESULTS: Macular edema occurred in 4 eyes(10.3%), 11 eyes(30.6%)and 2 eyes(4.4%)from the three groups respectively. 6 months after operation, compared to the A, C groups, macular edema from the group B were significantly different(χ²=4.821, 10.120; P<0.05). The best-corrected visual acuity of the group B was lower than the other groups(χ²=9.924, 12.101; P<0.05).

CONCLUSION: After treated with panretinal photocoagulation within short-term, cataract surgery might improve the risk of postoperative macular edema.