Characterization of the pupil light reflex, electroretinogram and tonometric parameters in healthy mouse eyes

Abstract

Purpose. To characterize the pupil light reflex (PLR), electroretinographic (ERG) and tonometric parameters which might be of importance for the in vivo characterization of mouse models of chronic ocular hypertension. Methods. C57/BL6 mice were used for experiments. The PLR was evaluated with a computerized pupillometer (n = 14), ERGs were recorded simultaneously from both eyes (n = 23) and IOP was measured with a modified Goldmann tonometer (n = 23). Results. The analysis of the PLR parameters confirmed the consensual PLR did not have significantly different amplitude (p > 0.1) and latency time (p > 0.1) compared to the direct PLR. However, PLR velocity (p = 0.004) was significantly smaller in the consensual PLR. Electroretinography revealed a-wave amplitude of 168.3 ± 9.6µV with latency of 27.5 ± 0.6 ms and b-wave 403 ± 28.8µV with latency of 22.7 ± 0.6 ms. The flicker ERG recording revealed amplitudes of 20.6 ± 2.4µV. Tonometry experiments revealed that modified Goldmann tonometer measurements correlated well with invasive manometry (r 2 = 0.89). The mean IOP of the mouse was 15.3 ± 0.6mmHg. Conclusions. Consensual PLR in mice is relatively slower than the direct PLR, but retains the same degree of constriction comparing to the direct PLR. A modified Goldmann tonometer seems to be a reliable non-invasive tool for IOP measurements in mice.