Early alterations of the retinal nerve fiber layer thickness caused by panretinal photocoagulation in diabetic retinopathy

Objective To investigate the early alterations of the retinal nerve fiber layer (RNFL)thickness caused by panretinal photocoagulation (PRP) treatment in patients with type 2 diabetes.Methods The RNFL thickness of all the participants was measured by optical coherence tomography (OCT).The selected patients accepted the PRP treatment for 4 times,once a week.The RNFL thickness was measured for continuous 4 weeks after the beginning of the PRP treatment.Results Compared with the control subjects,the RNFL thickness in patients with diabetic retinopathy (DR) decreased significantly (P ＜0.05 or P ＜0.01),but no statistical difference was observed between severe non-proliferative diabetic retinopathy (NPDR) and early proliferative diabetic retinopathy (PDR).The PRP treatment for DR could cause the early increase of the peripapillary RNFL thickness,especially in the superior and inferior quadrants (P ＜0.05 or P ＜0.01).The RNFL thickness increased along with the times of the PRP operation,and peaked for 3 times at 3 week3.Conclusions DR,either severe NPDR or early PDR,resulted in the decrease of the RNFL thickness in patients with type 2 diabetes.However,PRP treatment for DR can increase the RNFL thickness,due to the PRP caused lesion.The early alteration of the RNFL thickness may provide a valuable guide for the selection of the PRP parameters. Key words: Retinal nerve fiber layer; Panretinal photocoagulation; Diabetic retinopathy