Optomotry software

The measurements of retinal layers were performed using a Spectralis HRA + OCT device (Heidelberg Engineering, Germany) with several adaptions for rodents.²² The analysis and scanning protocols are described elsewhere^{11 (link),23} and in the eMethods, links.lww.com/NXI/A706, in line with the APOSTEL recommendations.^{24 (link)} Visual function analysis was performed with a testing chamber and OptoMotry software from CerebralMechanics, Canada, as previously described^{23 ,25 (link)} and explained in detail in the eMethods, links.lww.com/NXI/A706.

We assessed behavioral responses by measuring the spatial frequency threshold during OKT, as previously described,²⁵ (link) using rodent-specific OptoMotry software (Cerebral Mechanics). Briefly, a virtual cylinder was created that comprised a vertical sine wave grating projected onto four computer monitors that surrounded a platform that the mice were placed upon. The cylinder was rotated at 12 deg/s, and the head tracking was monitored via a video camera. The highest spatial frequency capable of driving the head tracking response was adopted as the threshold (photopic intensity, 142 cd/m²).

The spatial vision of both eyes was measured using the OptoMotry system (CerebralMechanics Inc., Lethbridge, Alberta, Canada) dependent on opto-kinetic response (OKR). In brief, mice were placed unrestrained on a platform in the center of four 17-inch LCD computer monitors (Dell, Phoenix, Arizona); their movement was captured by a video camera above the platform. A rotating cylinder with vertical sine wave grating was computed and projected to the four monitors by OptoMotry software (CerebralMechanics Inc., Lethbridge, Alberta, Canada). The sine wave grating provides a virtual-reality environment to measure the spatial acuity of left eye when rotated clockwise and right eye when rotated counterclockwise. When the mouse calmed down and stopped moving, the gray of the monitor immediately switched to a low spatial frequency (0.1 cycle/degree) for five seconds, in which the mouse was assessed by judging whether the head turned to track the grating. The mice were judged to be capable of tracking the grating. The spatial frequency was increased repeatedly until a maximum frequency was identified and recorded. The % of vision acuity was yielded by comparing the maximum frequency of the experimental eye to that of the contralateral eye. The investigator who judged the OKR was blinded to the treatment of the mice.