This study aims to compare the ability of the Freiburg Acuity and Contrast Test (FrACT) and Berkeley Rudimentary Vision Test (BRVT) to quantify visual acuity (VA) in patients who score non-numerical VA using standard charts and in artificially degraded subjects. Results will contribute to evidence-based clinical guidelines for measuring low vision.

This study aims to assess the effect of room illumination and chart luminance on visual acuity and contrast sensitivity. Results will provide an evidence-based recommendation on luminance and illumination levels that produce valid, repeatable and reliable visual acuity measures, and will serve as a basis for further studies on the effect of light on other visual parameters.

The notion that different diseases differ in their optical effect is simulated through the use of different types of artificial stimulus degradation — in particular dioptric and gaussian blur. With gaussian blur, VEP acuity, psychophysical grating acuity and Landolt C acuity are expected to show better agreement than with dioptric blur, where VEP and grating acuity are expected to deviate from Landolt C acuity.