Effect of wavelength in the efficacy for treatment of non-proliferative diabetic retinopathy / 中华眼底病杂志

ABSTRACT

Objective To compare the therapeutic effects of 577 nm laser and 532 nm laser panretinal photocoagulation (PRP) in the treatment of non-proliferative diabetic retinopathy (NPDR).Methods This is a prospective controlled study.A total of 23 patients (41 eyes) with clinically diagnosed severe NPDR were randomly divided into two groups including 577 nm group (11 patients,20 eyes) and the 532 nm group (12 patients,21 eyes).577 nm group and 532 nm group received 3-4 times PRP with single-point mode.The laser energy and the number of laser spots were compared,and the laser energy density was calculated.Before treatment and 1 day,1,3,6 and 12 months after treatment,the changes of best corrected visual acuity (BCVA),average threshold sensitivity,a/b-wave amplitude of flash ERG (F-ERG) in the 30°-60° visual field,and fundus fluorescein angiography (FFA) were compared between two groups.Results The response rate was 85.0％ and 23.8％,respectively in the 577 nm and 532 nm group,the difference was statistically significant (x2 =15.43,P ＜ 0.05).Compare to the pre-treatment measurement,the average threshold sensitivity,a/b wave amplitude of F-ERG and the 30°-60°visual field were reduced at 1 day after treatment both in the 577 nm and 532 nm group,the difference were statistically significant (F =8.68,7.57,4.52;P＜0.05).The average threshold sensitivity (t=2.41,3.48,1.23),a/b wave amplitude (a wavet=5.82,4.45,7.83;b wavet=5.40,3.23,4.67) of F-ERG were different between 577 nm and 532 nm group at 3,6 and 12 months after treatment (P＜0.05).There was no retinal neovascularization and non-perfusion region in two groups at 6 months after treatment.The average laser power were (436.25 ±54.65) and (446.43 ± 35.61) mW,number of laser spots were (1952.95 ± 299.09) and (2119.05 ± 302.69) spots,energy density were (7.60±1.30) and (7.60±3.00) mW× ms/μm2 in the 577 nm group and 532 nm group,respectively.There was no difference in average laser power (t=1.35),number of laser spots (t=2.85) and energy density (t=1.99) between two groups (P＞0.05).Conclusion Compared with the 532 nm laser,577 nm laser treatment has better visual outcomes for NPDR patients.