Visual Motor Responses in wild-type, eysKO and eysΔexon40-44 zebrafish. (A) A representative eye-specific Light-ON Visual Motor Response (VMR) from a single trial, presented as the distance moved (mm) per second, is shown for the time frame of 15 s prior to and after light alternation. Note that the response to light is less pronounced in the eysKO and eysΔexon40-44 larvae as compared to the strain- and age-matched wild-type larvae (5 dpf; n = 16 per group). (B) The distance moved (mm, mean of 4 Light-ON transitions per larva) during the first second after the Light-ON transition for wild-type, eysKO and eysΔexon40-44 zebrafish. The distance moved was significantly lower in the eysΔexon40-44 larvae (2.04 mm ± 0.66 (mean ± SD, n = 48)) than in wild-type larvae (2.72 mm ± 0.93 (mean ± SD, n = 48)), while no significant difference was observed between the eysKO larvae (1.75 mm ± 0.57 (mean ± SD, n = 47)) and eysΔexon40-44 larvae (5 dpf; n= 47 larvae). *** indicates p < 0.0001. Trials were conducted as 3 biological replicates containing all genotypes in each trial.