Abstract
Purpose :
To explore the effects of 430, 480, 530, and 580 nm monochromatic light on refractive development and the scleral extracellular matrix in guinea pigs, determine whether scleral MMP2 was involved in the changes observed.
Methods :
Fifty guinea pigs (black, brown, and white; 4 weeks old) were randomly divided into five groups(n=10/group),and irradiated with 430, 480, 530, and 580 nm and natural light (500 LUX) under a 12 h:12 h light–dark cycle. Ocular refraction and axial length were measured prior to and after 4 and 8 weeks of treatment. After 8 weeks of treatment, enucleated eyeballs were subjected to hematoxylin and eosin (H&E) staining and transmission electron microscopy to measure the thickness and fiber diameter of sclera, protein extracted from sclera were determined by Western blotting.
Results :
After 4 and 8 weeks of exposure, compared to the natural light group, myopia can be induced by 530 and 580 nm wavelength light, were shown the longer axial length (p<0.001,p<0.01)and decreased refraction(p<0.001,p<0.01); while the axial lengths of the 430 and 480 nm groups were significantly shorter (p<0.001,p<0.001)and refractions were more hyperopic(p<0.001,p<0.001). In addition, the thickness and fiber diameter of sclera thinned in the 530 and 580 nm groups(p<0.001,p<0.01); in the 430 nm and 480 nm groups, the thickness and fiber diameter of sclera were relatively thicker(p<0.001,p<0.001). Finally, Western blotting showed that, compared to the natural light group, the scleral MMP2 level increased in the 530 and 580 nm groups (p<0.05,p<0.05).
Conclusions :
Monochromatic light of different wavelengths affects the refractive development of guinea pigs. Long-wavelength (530 and 580 nm) light induces myopia; short-wavelength (430 and 480 nm) light induces hyperopia. In guinea pigs with light-induced myopia , scleral MMP2 protein expression was upregulated,this elevation may cause the longer axial length.
This is a 2020 ARVO Annual Meeting abstract.