Abstract
Purpose :
Myopia and astigmatism are two main types of refractive errors, a very common eye disorder with problems focusing images accurately on the retina. The study is to explore the biophysical responses of retinal ganglion cells (RGCs) to focused/defocused under stretching to mimic myopic status and astigmatic blur image projection to mimic astigmatism on the mouse retina.
Methods :
Adult wild-type (WT) mice of either sex (postnatal day 16–56) C57BL/6J (RRID: and connexin36 knockout (Cx36 KO) mouse retinas were used in the study. Extracellular and whole-cell recordings were obtained from single alpha(α) RGCs of the mid-peripheral retina in the nasotemporal plane. Under the 40x objective, the 15 µm diameter pixels of a green organic light-emitting display OLED (OLEDXL, Olightek, Kunming, Yunnan, China; 800 × 600-pixel resolution, 85 Hz refresh rate) presented 0.25 µm/pixel were projected onto the photoreceptor layer. Myopic and astigmatism focused/defocused 125 µm diameter of 0.0067 cycles/degree image was projected.
Results :
As previously reported, compared with focused images, defocused images showed a significantly decreased amplitude (p<0.05) of EPSC in ON (n = 9) and OFF αRGCs (n = 9). A negative pressure side (approximately 5000 Pa) was conducted with a giant glass microelectrode on the soma of the cell to stretch 5% increase in diameter of the αRGC. The αRGCs (n = 10) also show significant differences in the amplitude of EPSCs (p< 0.05) between focused and defocused images. Similar results (p<0.05) were observed by elongating αRGCs (n = 10) by stretching retinas. But this is not the case in the αRGCs (n = 10) in Cx36 knockout mice as a control group (p > 0.05). A 20µm x 200µm light bar generated by the Mightex Polygon1000 system was projected on the RGCs with the suction pipette to twist the soma of αRGCs. The αRGC (n = 15) showed no difference in spike amplitude (p > 0.05) to the different angle projections. But The αRGC (n = 15) had significant responses (p < 0.05) differences between the focused and astigmatism-defocused images. αRGC (n = 6) in Cx36 KO mice had no differences as control (p >0.05).
Conclusions :
Our results indicate that αRGCs can respond to focused and defocused images in both normal and myopic mouse retinas. αRGCs can also reflect the focused and astigmatism-defocused image. RGCs in retinas might sense refractive errors in the mouse.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.