Abstract
Purpose :
To characterize the guinea pig contact lens (CL) induced myopia model, the temporal profile of short-term ocular changes both during induction and after treatment is terminated.
Methods :
To induce myopia, 2-week-old pigmented guinea pigs (New Zealand strain, n = 8) wore monocular -10 D rigid gas-permeable (RGP) CLs for one week, while the fellow eye served as a control. Ocular measurements were made at baseline, 3, and 7 days after initiation of CL wear. The CL treatment was then terminated on day 7, and additional measurements were made 3, 7, and 14 days later. Measurements included retinoscopy (spherical equivalent refractive error; SE), noncontact optical biometry (axial length, AL), and spectral-domain optical coherence tomography (choroidal and scleral thicknesses; ChT & ScT).
Results :
Mean interocular differences (treated - fellow) in SE and AL were significantly different from baseline after 3 and 7 days of CL wear (p < 0.0001). ChT was also significantly reduced by day 7 of CL wear (p = 0.004). Interestingly, while both SEs and ALs of treated eyes recovered fully within 7 days of CL removal, the earlier ChT thinning, during the induction phase, was replaced by sustained thickening compared to baseline values, remaining significantly so on day 7 (p = 0.009), but returning to the normal by day 14. While ChT changes would have contributed to AL changes, they were much smaller in magnitude than AL changes in both phases. Interocular differences in ScT showed no significant changes.
Conclusions :
The above patterns of myopia induction and recovery validate this negative RGP-CL model as an alternative to traditional spectacle lens models, at least for guinea pigs. The scaling mismatch between ChT and AL changes warrants further investigation in relation to underlying mechanisms.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.