An open-source platform for measuring optomotor responses in mice

The optomotor response (OMR) is a valuable behavioral index for assessing visual function in basic research; however, commercially available OMR evaluation equipment is expensive and lacks flexibility, as proprietary software and fixed hardware geometry restrict custom stimulus protocols and system modifications. Alternative low-cost, non-OMR methods often require extensive animal pre-training and are unsuitable for high-throughput studies. To overcome these limitations, we developed a low-cost, open-source OMR recording system for mice that lowers both financial and practical barriers, thereby facilitating widespread adoption across laboratories. Following a one-hour training session for evaluators, the system enabled precise quantification of visual acuity and assessment of contrast sensitivity in normal-sighted mice, detection of age-related visual decline, and evaluation of OMR extinction in retinitis pigmentosa model mice. This system facilitates accessible and efficient assessment of visual function in vision research.