Abstract
Purpose :
First, to understand the impact on refractive and structural changes on onset and progression of myopia in 3 guinea pigs models a) lens-induced myopic model (LIM), b) natural progression myopic model (NM) and c) “naturally resistant to myopia” model (NRM). Second, to identify and validate the most appropriate guinea pig model with predictive myopia progression to study myopia control intervention strategies and its translation to human myopia progression.
Methods :
Dunkin Hartley albino (n = 42) and Elm Hill pigmented strains (n = 30) were used in this study. Myopia was induced experimentally on the right eyes for both strains of hyperopic animals by affixing a negative (-4 D) lens over them on P7. Left eyes were attached with the Plano lens to serve as controls. Myopia induction was followed for 1day (n = 8), 5days (n = 8) and 10days (n = 8). Biometry measurements, refraction, and ocular imaging were performed pre and post-induction. The thickness of the sclera, choroid, retina, anterior chamber depth (ACD), vitreous chamber depth (VCD), central corneal thickness (CCT) was measured with a built-in caliper.
Results :
Albino GPs were classified as exhibiting spontaneous myopia if the refractive error was more than -3D at P7 and it increased over time (P8: -3.5±1.1D; P12: -5.5±1.1D; P17: -6±1.9D). Based on 2 batches of experiments, significant differences in refractive measurements, biometry and in 3 models were determined. There were differences between LIM and NRM refractive error (-6.8±1.6D vs +4.2±1.5); Axial length (8.62±0.54mm vs 7.44±0.39mm); thickness of sclera (93±19µm vs 152±20µm, p<0.01), choroid (52±14µm vs. 121±18µm, p<0.01), retina (140±4µm vs. 168±5µm, p<0.01), VCD (3.92±0.22mm vs. 3.31±0.16mm, p<0.01) and CCT (181±37µm vs. 220±15µm, p<0.01), but not of ACD. The thickness of the sclera, choroid, retina, ACD, VCD, and CCT did not significantly differ between LIM and NM groups.
Conclusions :
These study results suggest that the difference in refractive changes may have an association between central corneal thickness and posterior segment changes in GPs. This also supports that central corneal thickness changes may serve as a biomarker of posterior segment changes and subsequent pathology.
This is a 2020 ARVO Annual Meeting abstract.