Comparison of supra scan and krypton yellow laser photocoagulation in treatment of diabetic retinopathy

Objective To investigate the effects of pan-retinal photocoagulation (PRP) with supra scan laser on the severe non-proliferative diabetic retinopathy and to analyze the affect of retinal structure and function after laser photocoagulation by optical coherence tomography (OCT) and multifocal electroretinogram (mfERG).Methods Sixty-four eyes of 53 severe non-proliferative diabetic retinopathy patients were assigned randomly to receive either supra scan laser or krypton yellow laser treatment.Follow up examinations were performed 3 months,the best corrected visual acuity (BCVA),slit-lamp biomicroscopy,ophthalmoscopy,fudus fluorescein angiography (FFA),OCT and mfERG were performed before treatment.One week,1 month,3 months after treatment,BCVA,OCT and mfERG were examined.The differences between two groups were compared.Results The central subfield thickness increased in both groups after treatment,there was especially obvious increase in the control group,there was no statistical difference in both group (P ＞0.05),the P1,N1 waves amplitude had various loss and reached the lowest level at 1 week after treatment and recovered gradually from 1 month to 3 months after treatment,the amplitude of control group decreased more significantly and recovered more slowly compared to the test group.Conclusions Supra scan laser photocoagulation for DR is as effective as krypton yellow laser,and reduces the damage at the same time. Key words: Diabetic retinopathy; Laser photocoagulation; Optical coherence tomography; Multifocal electroretinogram