Comparing Effect Of Single-Point And Multi-Point Scanning Laser On Retinal Structure And Function In Patients With Non-Proliferative Diabetic Retinopathy

Objection:To analyze and compare the effect of multi-point and single-point scanning mode panretinal photocoagulation on retinal structure and function in patients with non-proliferative diabetic retinopathy(NPDR).Methods:A retrospective case study.57 patients(93 eyes)who were clinically diagnosed as severe NPDR and treated with panrentinal photocoagulation(PRP)in Qingdao Municipal Hospital Affiliated to Qingdao University from January 2019 to July 2020were analyzed retrospectively.The patients were divided into control group(single-point mode group)and observation group(multi-point scanning mode group)according to the different laser mode selection during PRP.In the control group,27 patients(46 eyes)were performed in single-point mode in 3～4 times,including 17 males(29 eyes)and 10females(17 eyes),with an average age of(62.37±9.36)years,average diabetes duration of(11.37±4.34)years,average glycosylated hemoglobin(Hb A1c)of(6.85±0.67)%,and average serum creatinine level of(69.41±17.32)μmol/L.In the observation group,30patients(47 eyes)underwent 532nm multi-point scanning mode in 2 times,including 15males(22 eyes)and 15 females(27 eyes),with an average age of(61.74±8.48)years,average diabetes duration of(12.49±6.50)years,average glycosylated hemoglobin(Hb A1c)of(7.05±0.74)%,and average serum creatinine level of(71.30±16.92)μmol/L.The pain grade,laser parameters,the mean sensitivity(MS)in the 30°～60°visual field,a/b-wave amplitude of flash electroretinogram(F-ERG),and the central macular thickness(CMT)were compared between the two groups.The pain scores according to the Numerical Rating Scale(NRS)on the data after laser treatment was statistically analyzed.The laser energy,the number of laser spots and spot diameter were recorded,the energy density were calculated,and the statistical analysis and comparison were made between the two groups.To observe the mean sensitivity(MS)in the 30°～60°visual field,a/b-wave amplitude of flash electroretinogram(F-ERG),and the central macular thickness(CMT)were compared between the two groups at 1 day,1 month,3 months,and 6 months after treatment.The non-perfusion area(NPA)was measured at preoperative 1 day and neovascularization based on fundus fluorescein angiography(FFA)was observed at 6 months after treatment.All the data was analyzed by SPSS 23.0statistical.The classified data were compared byχ~2test.The independent-samples T test was used for the pain score,laser parameters and other measurement data comparison between group.The data of the mean sensitivity,a/b-wave amplitude of F-ERG,and CMT were analyzed by two-factor repeated measures ANOVA.If the data did not conform to Mauchly’s test of sphericity,the calibration coefficient was used to calibrate the degree of free.P<0.05 was considered statistically significant.Results:There were no significant differences in age,sex composition ratio,duration of diabetes,BMI,Hb A1c and serum creatinine levels,history of alcohol consumption,smoking and family history between the control group and the observation group(P>0.05).The postoperative pain score of observation group was(1.49±0.95),which was significantly lower than that of control group(2.57±0.50)(t=6.840,P<0.001).There was significant difference in laser energy and energy density between the two groups(t=0.240,P=0.021;t=12.840,P<0.001),but there was no significant difference in the number of laser spots between the two groups(t=-1.490,P=0.139).After treatment,1 month and 3months,the mean sensitivity,a-wave amplitude of F-ERG and the central macular thickness range of the control group and the observation group were significantly different from those 1 day before treatment(P<0.001).The amplitudes of 1 month,3months and 6 months F-ERG b waves after treatment were significantly lower than those before treatment(P<0.001).There was no significant difference about NPA 1 day preoperatively(P>0.05).FFA at postoperative 6 months showed no neovascularization and obvious perfusion area in both groups.Conclusion:1.There was no difference about retinal structure and function in patients with severe NPDR treated with 532nm multi-point laser and single-point scanning mode at 6months postoperatively.2.The multi-point scanning mode laser can improve the treatment comfort of patients with shorter treatment time and less pain.