Glare

Glare is an important consideration for everyone; even for those with 20/20 visual acuity. It becomes even more important in those eyes with compromised vision due to ocular disease and in individuals with medical conditions that can either impact on glare sensitivity through their effects on the eyes and vision or through side effects of medications used to treat them.

Problems with glare can impact on many aspects of the everyday visual lifestyle, hindering such common activities as driving, using a computer, watching television, or simply being outdoors. Healthy Sight Counseling in the customized eyeglass prescription offers at least a partial solution to the problem of glare through the use of eyeglass lens enhancements.

What Is Glare?

It is defined as the loss of visual performance or visibility, or the annoyance or discomfort produced by luminance in the visual field that is of greater intensity than the ambient light to which the eyes have adapted. Glare results from excessive or misdirected light, or stated differently, incidental or sudden luminance that is higher than the background illumination.

Luminance is quantified in terms of the lumen, a unit of measurement of the amount of light incident upon a surface. Higher luminance indicates increased brightness. Optimal lighting for human vision ranges from 100 to 1400 lumens. Table 1 shows examples of typical luminance levels in some common environments.