Optokinetic Response Assay: A Method to Measure Visual Acuity in Zebrafish

- Secure an anesthetized fish on a platform with its eyes and gills extending beyond the platform's edge. Position the fish upright in a water-filled cylinder within a well-lit drum that can rotate freely. Once the fish revives, indicated by gill and eye movement, place a grating or pattern of alternating white and black vertical stripes into the drum. Now place a solid black occluder over the stripes in the view of the left eye.

Begin the rotation and record the optokinetic response, OKR, for the right eye. The OKR consists of reflexive eye movements in response to a visual stimulus. Replace the pattern with smaller and smaller black and white stripes until eye movement is no longer observed. Perform the same procedure for the left eye.

To calculate monocular visual acuity, the ability to distinguish fine details, measure the distance from the center of the lens of the eye to the pattern and the length of the smallest pattern of a pair of white and black stripe at which eye movement was observed. In the example protocol, we will use the optokinetic response to measure monocular and binocular visual acuity in adult zebrafish.

- Optokinetic studies are carried out with a custom-buil