Literature Update: Application of the ICare Tonolab Rodent Tonometer in Glaucoma Research
Release time:
2025-09-25
Prospective studies confirm that the ICare Tonolab rodent tonometer is the reliable gold standard for monitoring intraocular pressure changes in mouse models of glaucoma.
Objective
Glaucoma is a neurodegenerative disease characterized by elevated intraocular pressure (IOP), which leads to progressive retinal ganglion cell (RGC) loss and visual impairment. The primary objective of this study is to investigate the correlation between IOP and morphological, functional, and behavioral parameters in a mouse model of magnetic microbead-induced glaucoma.
Methods
Elevated intraocular pressure (IOP) was induced in 10-week-old male C57BL/6JRj mice (N=14) through intracameral unilateral injection of magnetic microbeads on Day 0. IOP was monitored using the Tonolab rebound tonometer up to Day 31 post-induction. On week 4 post-induction, spectral-domain optical coherence tomography (SD-OCT) imaging was performed to quantify the inner retinal thickness (INL). Pattern electroretinography (pERG) was recorded to assess retinal ganglion cell function. In addition, visual acuity (VA) and contrast sensitivity (CS) were evaluated on Day 31. On the same day mice were sacrificed, retinas were collected for retinal ganglion cell immunostaining with anti-RBPMS antibody and quantification of RBPMS-positive cells using stereology.
Results
IOP was significantly elevated by Day 3 as compared to contralateral eyes (17.6 ± 1.3 vs. 10.1 ± 0.1 mm Hg) and remained significantly elevated throughout the whole follow-up period of 31 days. On Day 31, INL thickness was significant decreased in microbead-injected eyes as compared to naïve eyes (85.7 ± 3.7 vs. 97.6 ± 0.5 µm, respectively, P<0.001). Similarly, microbead-injected eyes had significantly decreased pERG amplitude (2.4 ± 0.6 vs. 6.0 ± 1.0 µV, P=0.007) as compared to naïve eyes. Furthermore, a significant decrease was observed in both optomotor reflex parameters VA (0.178 ± 0.038 vs. 0.389 ± 0.001 cycles/°, P<0.001) and CS (52.0 ± 16.5 vs. 8.4 ± 0.7 %, P=0.03) in microbead-injected eyes as compared to naïve animals. The number of RBPMS-positive cells decreased by 28% in the microbead-injected eyes as compared to healthy contraletaral eyes (2192 ± 102 vs. 3040 ± 69 cells/mm2, P<0.001). Cumulative IOP showed no significant correlation with INL thickness, OMR measurements or RBPMS-positive cell numbers, but significantly correlated with pERG amplitudes (r = -0.7545, P<0.005).
Conclusions
Cumulative IOP has a significant correlation with RGC function in the magnetic microbead-injected mouse model.
References： https://experimentica.com/scientific_pub/arvo-2025-presentation-microbead-induced-mouse-glaucoma-model/
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