Abstract
Purpose: :
Zebrafish (Danio rerio) has found its way into visual research because of its excellent visual system with a cone-dominated retina. Up to now, no empirical data about the visual acuity of adult zebrafish are available. However, a standardized and reliable method for visual acuity (VA) measurements is a prerequisite to analyze genetically modified fish lines and to evaluate the effect of pharmacological or genetic interventions in the visual system. The aim of the present study was to evaluate the VA and contrast sensitivity of adult zebrafish based on optokinetic reflex measurements.
Methods: :
Using a modified commercially available optomotor device (OptoMotry®, CerebralMechanics, Lethbridge, AB, Canada), virtual three-dimensional gratings of variable spatial frequency and contrast were presented to adult zebrafish (n=6). In a first experiment, visual acuity was evaluated by changing the spatial frequency at different angular velocities (10, 15, 20, 25, and 30 degrees/second). Thereafter, visual acuity (VA) was evaluated at different contrast levels (2.5, 5, 10, 20, 40, 80 and 100 %).
Results: :
At the different tested angular velocities (10, 15, 20, 25, and 30 degrees/second) and a contrast of 100%, VA values ranged from 0.56 to 0.58 cycles/degree. Correlation of visual acuity with contrast sensitivity was highly significant (p<0.0001).
Conclusions: :
Visual acuity measurements in adult zebrafish with the OptoMotry® device are feasible and reliable. The values reveal a remarkably higher VA and contrast sensitivity compared to larval zebrafish and mice. The system is a useful device to increase the impact of adult zebrafish in vision research.
Keywords: perception • temporal vision