Abstract： Objective To compare the effect of 650nm semiconductor laser with different irradiation duration on the retinal thickness of guinea pigs with form-deprived myopia(FDM).Methods The FDM guinea pigs model was established by means of headgear and were divided into the normal control group(n=10),simply covered group(n=10)and covered+laser irradiation group.Guinea pigs in the covered+laser irradiation group received 650nm laser irradiation twice a day.They were divided into 3min group(n=10),6min group(n=10)and 12min group(n=10)according to different irradiation duration.After 4 weeks,the diopter values of each group were measured by strip photoscope,and the posterior pole retinal thickness of each guinea pigs was measured by Optical Coherence Tomography(OCT).The differences of eyeball diopter and retinal thickness among all groups were analyzed and compared.Results The diopter of simply covered group was significantly more myopic than that in the normal control group(P<0.05).The diopter value of the hiding+laser irradiation group was lower than that in the simply covered group,and the 6 min group and 12min group were lower than that in the 3min group(P<0.05).However,there was no significant difference in myopia diopter between 6 min group and 12min group(P>0.05).The posterior polar retinal thickness of the simply covered group was significantly thinner than that in the normal group(P<0.05).The retinal thickness of the hiding+laser irradiation group increased compared with that in the simply covered group(P<0.05).The retinal thickness of the 6min group and 12min group increased compared with that in the 3min group(P<0.05).However,there was no significant difference in retinal thickness between 6min group and 12min group(P>0.05).Conclusion 650nm semiconductor laser can control the development of form-deprived myopia and improve the tendency of retinal thinning in guinea pigs.