Clinically, glare is one of the most common visual complaints. Fortunately, it is also one of the most easily remedied. The use of antireflective (AR) coatings in combination with photochromic eyeglass lenses is a simple and effective way to minimize the effects of everyday distracting and discomforting glare. The use of photochromic, tinted, or polarized lenses will reduce disabling glare and help alleviate its adverse affects on quality of vision and promote a more satisfactory visual experience. In extreme conditions, polarized lenses will help reduce blinding glare.
The Difference Between Glare and Contrast Sensitivity
Because glare is often used in testing contrast sensitivity, there may be some confusion about the difference between the two. While glare is luminance in the visual field that is greater than the ambient illuminance, resulting in compromised visual performance, contrast sensitivity refers to the ability of the visual system to differentiate various shades of gray, or variations in reflected luminance. Glare and contrast are intimately related; when glare is present, contrast sensitivity will be compromised.
- Contrast sensitivity tests measure the amount of contrast necessary to recognize a target with various gradations of reflected visual luminance
- Glare sensitivity tests measure the change in visual function that results from a glare source in another part of the field of vision
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Testing Glare Sensitivity
Glare sensitivity can be tested using contrast detection tasks or by acuity-based measures. The majority of glare tests in current use assess the effects of glare on contrast sensitivity by measuring contrast thresholds in the presence or absence of glare.