The Study Of Clinical Applications For Supra Scan Laser Photocoagulation In Diabetic Retinopathy

ObjectiveTo investigate the effects of pan-retinal photocoagulation (PRP) with supra scan laser on the severe non-proliferative diabetic retinopathy by Optical Coherence Tomography (OCT) and multifocal electroretinogram (mfERG), to analyze the afftect of retina structure and function after laser photocoagulation, it is expected to supply some important data for objectively evaluating the effect of photocoagulation with supra scan laser.Methods1.64 eyes of 53 patients who were diagnosed as severe non-proliferative diabetic retinopathy (NPDR) from April 2010 to November 2010 at Tianjin Eye Hospital were recruited and divided into two groups, the control group and the test group, there were 32 eyes in each group. Eyes in the control group were treated with panretinal photocoagulation by multiple wavelength laser while the test group treated with panretinal photocoagulation by supra scan laser. The best corrected visual acuity (BCVA), slit-lamp biomicroscropy, ophthalmoscopy, fudus fluorescein angiography (FFA), OCT and mfERG were performed before treatment.1 week,1month,3 months after treatment, BCVA, OCT and mfERG were examined..2. Statistical method:the data were analyzed by 17.0 statistical software with methods of independent-sample t test, repeated measure ANOVA, P<0.05 as the standard of significant difference in statistic.Results1. The visual acuity of patients in both the control group and the test group had various loss at the 1 week after laser treatment, there was especially obvious drop in the control group. The symptom lightened at the 1 month after treatment. At 3 month after treatment there was no statistical difference in visual acuity in both groups. There was no statistical difference in visual acuity at the 3 month after treatment compared with pre-treatment.2. The macular fovea thickness increased in both groups after treatment. there was especially obvious increase in the control group, there was no statistical difference in both groups(P>0.05). The macular fovea thickness decreased in both group at 1 week after treatment, there was especially obvious drop in the test group, there was no statistical difference in both groups(P>0.05).The macular fovea thickness in the test group at 3 month after treatment especially obvious drop. There was no statistical difference in the macular fovea at the 3 month after treatment compared with pre-treatment(P>0.05). There was no statistical difference in both groups in the macular fovea at the 3 month after treatment(P>0.05).3. After the laser photocoagulation, the P1, N1 amplitude had various loss and reach the lowest level at 1 week after treatment and recovered gradually from 1 month to 3 month after treatment. Compared to the test group, the P1, N1 amplitude decreased more significantly in control group and recovered more slowly. The P1, N1 implicit time had significant delayed in both control group and the test group,the recover of P1, N1 implicit time in test group better than control group.ConclusionAmong the patients of severe NPDR, after supra scan laser photocoagulation treatment, the extent of the macular fovea thickness increased and the macular function significantly decreased in a short period because of the effects of laser damage, then it seems to recovery in the following observation period. Supra scan laser photocoagulation for DR is as effective as classic laser treatment and reduce the damage at the same time.