[Evaluation and comparison of visual acuity measurement methods in developing C57BL/6J mice]

Objective: To investigate the developmental characteristics of visual acuity in C57BL/6J mice and to evaluate the consistency and reliability of different measurement methods. Methods: This was an experimental study. One hundred and seventy-two C57BL/6J mice were divided into eight groups based on postnatal days (P): P13/14 (first day of eye opening,18 mice), P15 (11 mice), P16 (10 mice), P18 (21 mice), P21 (onset of the critical period for visual development, 29 mice), P28 (peak of the critical period, 28 mice), P35 (end of the critical period, 25 mice), and P60 (adulthood, 30 mice). Visual acuity was assessed using three methods: visual evoked potentials (VEP), the optomotor reflex (OMR) task, and the visual water task (VWT). Statistical analyses were conducted using the least significant difference t-test, one-way ANOVA, and independent sample t-tests. Results: VEP measurements of monocular visual acuity showed that the visual acuity in the P13/14 group was (0.20±0.06) cycles per degree (cpd), and increased to (0.44±0.08) cpd in the P21 group and (0.52±0.06) cpd in the P35 group, with significant differences between groups (all P<0.05). The visual acuity in the P60 group was (0.56±0.05) cpd, which was not significantly different from that in the P35 group (P>0.05). For binocular visual acuity assessed by the OMR task, the P13/14 group had a visual acuity of (0.11±0.06) cpd, which increased to (0.20±0.07) cpd in the P15 group, (0.35±0.05) cpd in the P16 group, (0.40±0.05) cpd in the P18 group, and (0.47±0.05) cpd in the P21 group, with significant differences between groups (all P<0.05). The visual acuity in the P60 group was (0.50±0.05) cpd, which was not significantly different from that in the P21 group (P>0.05). The binocular visual acuity assessed by the VWT in the P60 group was (0.50±0.03) cpd. There was no significant difference in visual acuity measured using the three methods in the P60 group (P>0.05). Conclusions: Visual acuity in C57BL/6J mice increased rapidly from the first day of eye opening to the onset of the critical period for visual development, followed by a slower increase until adulthood. In adult C57BL/6J mice, it ranged from 0.50 to 0.56 cpd, as measured using the VEP, OMR task, and VWT, which can yield comparable and reliable results.