Construction of a mouse defocus myopia model based on an anti-scratch device and changes in ocular OCT parameters

Objective  To build a mouse model of defocus myopia based on an anti-scratch device and dynamically analyze changes in the ocular parameters using optical coherence tomography (OCT).

Methods  Twenty SPF-grade 21-day-old C57BL/6J mice were selected and randomly divided into a defocus group and a normal control group using the random number table method, with 10 mice in each group. Mice in the defocus group wore an anti-scratch defocus device containing a -25.00 D lens on their right eyes. Mice in the normal control group were not subjected to special treatment. On days 7, 14, 21, and 28 after modeling, diopter was measured using a viroscope, and axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous cavity depth (VCD), retinal thickness (RT) and choroidal thickness (ChT) were measured using OCT. During the experiment, the device wear and activity status of the mice were observed, and whether the lens was scratched and the anterior segment status of the mice were observed under a slit lamp microscope. The care and use of experimental animals followed the Guide for the Care and Use of Laboratory Animals, and the experimental protocol was approved by the Animal Research Ethics Committee of the Anhui University of Science and Technology First Affiliated Hospital (No. 2025-SY-Q001-001).

Results  Four weeks after modeling, the right eye refraction, AL and RT were + 0.02(-0.25, + 0.10)D, 3.39(3.36, 3.45)mm, 0.16(0.14, 0.19)mm in the normal control group, respectively, and -2.21(-2.54, -1.29)D, 3.66(3.61, 3.76)mm, and 0.20(0.18, 0.21)mm in the defocus group, respectively. Compared with the normal control group, the right eye refraction of mice in the defocus group decreased, AL increased, and RT thickened, with statistically significant differences ( Z=-3.790, -3.638, -2.576; all P<0.05). There were statistically significant overall differences in refraction, AL, ACD, LT, VCD, RT and ChT in the defocus group at different time points after modeling ( H=34.647, 35.136, 26.844, 10.978, 19.347, 18.269, 27.082; all P<0.05). Among them, at 3 weeks of modeling, the refractive power decreased compared with 1 week of modeling, AL and LT increased compared with 1 week of modeling, ACD, VCD, and RT increased compared with 1 and 2 weeks of modeling, and ChT became thinner compared with 1 week of modeling (all P<0.001). At 4 weeks of modeling, the refraction decreased compared with 1, 2, and 3 weeks of modeling, AL and RT increased compared with 1 and 2 weeks of modeling, ACD increased compared with 1 week of modeling, and VCD and ChT decreased compared with 1 and 2 weeks of modeling (all P<0.001). During the experiment, no lens detachment and obvious scratches were found; the mice were in normal activity, and no obvious stress reaction or eye infection was observed.

Conclusions  The anti-scratch defocus device has good stability and can successfully induce myopic phenotypes in mice. The decrease in refraction of the defocus myopia model is related to the increase of AL, thinning of ChT and thickening of RT.