Abstract: Objective  Investigate the effects of instantaneous biomechanical forces on retinal ganglion cells (RGCs). Design  Experimental research. Participants 35 C57BL/6J mice. Methods Eight-week-old C57BL/6J mice were randomly assigned to groups (control group, 10-day eye rubbing group, 20-day eye rubbing group, 30-day eye rubbing group). Erythromycin eye ointment was applied to the left eye of the mice three times daily at 4-hour intervals to induce the mice to rub their eyes with both forepaws, mimicking the transient biomechanical forces generated during human eye rubbing. The frequency of eye rubbing was continuously monitored using video recording. After 10, 20, and 30 days of eye rubbing, the retinas were isolated, and immunofluorescence staining was performed to label RGCs, followed by quantitative analysis of the changes in RGC numbers in the peripheral, intermediate, and central regions of the retina. Main Outcome Measures The number of RGCs. Results One hour after applying erythromycin eye ointment, the frequency of mice rubbing their left eyes increased by 6.23 times compared to the control (P<0.0001), and the frequency of rubbing their right eyes increased by 3.39 times compared to the control (P<0.01). In the peripheral retinal region, after 20 days of eye rubbing, the number of RGCs in the left eye decreased by 8.3% compared to the control (P<0.01), while the number of RGCs in the right eye showed no significant change (P>0.05); after 30 days of eye rubbing, the number of RGCs in the left eye decreased by 11.7% compared to the control (P<0.001), and the number of RGCs in the right eye decreased by 9.7% compared to the control (P<0.01). In the mid-peripheral retinal region, after 30 days of eye rubbing, the number of RGCs in the left eye decreased by 6.9% compared to the control (P<0.05), while the number of RGCs in the right eye showed a decrease compared to the control, but without statistical significance (P>0.05). In the central retinal region, the number of RGCs in both the left and right eyes showed no significant change at any time point. At the same time point, there was no obvious difference in the number of RGCs between the left and right eyes in the same retinal region. Conclusions Long-term eye rubbing leads to a reduction in the number of RGCs in mice, with damage showing a time-accumulated effect; compared to the central and intermediate regions, RGCs in the peripheral region exhibit higher susceptibility to instantaneous biomechanical fluctuations; low-frequency eye rubbing does not show a significant difference in RGC damage compared to high-frequency eye rubbing.

Key words: Rubbing, Transient mechanical stimuli, Retinal ganglion cells, Glaucoma