AIM: To observe the visual acuity after pars plana vitrectomy(PPV)and panretinal photocoagulation in severe proliferative diabetic retinopathy(PDR).

METHODS: Totally 93 cases with severe PDR were randomly divided into 2 groups. Group 1 were treated with PPV + membrane peeling +panretinal photocoagulation +focal or grid macular laser. Group 2 were treated with panretinal photocoagulation + focal or grid macular laser. Follow-up was at least 12 months.

RESULTS: At postoperative one year, visual acuity in group 1 improved in 12 eyes(27.9%), unchanged in 11 eyes(25.6%), decreased in 20 eyes(46.5%). In group 2, visual acuity improved in 14 eyes(28.0%), unchanged in 24 eyes(48.0%), decreased in 12 eyes(24.0%). The percentage of improvement in 2 groups has no statistical significant difference, whereas the stabilized and worsened eyes in group 1 and group 2 were significantly different.

CONCLUSION: PPV may worsen the visual acuity of the patients with severe PDR, compared with the panretinal photocoagulation.