Glare is a visual impairment that occurs when the amount of light entering the eye is greater than the eye's ability to manage the light. Glare reduces visual contrast, resulting in symptoms of discomfort, poor vision or temporary blindness. Haloes are another glare symptom, usually seen as glowing auras or "starbursts" around bright
lights. Glare recovery is a measure of how quickly an individual's vision normalizes after exposure to glare. There are three different types of glare:
: This type of glare occurs when the eye is exposed to sudden fluctuations of light brightness. For example, when driving on a sunny day there will be direct luminescence, broken up by shadows when the sun is blocked, combined with reflections of sunlight off the road and other cars. All of these light fluctuations cause the pupil to dilate and constrict, while inside the eye rod cells and cone cells struggle to adapt to the shifting light conditions. The resulting glare causes discomfort and annoyance, but visual impairment is minimal.
: Also known as disability glare
, this type of glare can be caused by misdirected light that confuses the retina and reduces visual contrast. Veiling glare is commonly associated with cataracts, in which the eye's lens becomes cloudy. Cataracts diffuse the light in random, unexpected patterns -- a phenomenon known as "Rayleigh scatter." Veiling glare is also caused when there is simply too much bright light for the eye to handle; for example, when facing high-beam headlights of oncoming traffic while driving. Veiling/disability glare significantly impairs visual performance.
: Some individuals are extremely sensitive to light, a condition known as photophobia. These individuals are also more susceptible to dazzling glare, because they do not adapt easily to changes in light and are slower to recover from glare. In addition to light sensitivity, dazzling glare is associated with retinal dysfunction such as retinitis pigmentosa, retinal detachment, and age-related retinal issues. Anything that leads to retinal damage may increase sensitivity to light and dazzling glare. Dazzling glare can be overwhelming, and often causes temporary blindness.
Contributing Factors to Glare and Haloes
While most everyone experiences glare at some point, the following factors are known to exacerbate glare and halo problems:
: With age, glare problems tend to get worse. That's because aging eyes are increasingly sensitive to light and take longer to adjust to light fluctuations.
: Those with lighter-colored eyes generally have greater sensitivity to bright light. Glare problems are more prevalent in light-eyed populations.
: LASIK surgery and some other corrective vision procedures are associated with glare and halo vision problems.
: Cataracts, scratched corneas, slow rhodopsin regeneration, retinal health issues, dry eye and other eye conditions may be a contributing cause to glare and halo vision problems.
Managing Glare and Halo Symptoms
Consulting with an eye health professional is recommended when glare and haloes interfere with vision and quality of life. A professional eye exam is especially important to rule out the possibility of cataracts, which are strongly associated with glare and halo symptoms. Early detection of cataracts improves treatment outlook. Eye health professionals may also recommend the following self-care practices to assist with glare and halo problems:
Wide-brimmed hat or visor: Protecting the eyes with a wide-brimmed hat or visor helps to block short-wave visible wavelengths from reaching the eye, thereby reducing blinding glare. Although visors help minimize light from overhead, they do not help with reflected horizontal light.
Sunglasses: Sunglasses are helpful in reducing glare and haloes, especially when combined with a wide-brimmed hat. Short-wavelength light creates the most glare, so sunglasses with a yellow, orange or red tint may be most effective at reducing glare. Polarized lenses are also recommended to reduce the horizontally-oriented glare of reflected sunlight.
Surgery: In cases of cataracts, surgery that replaces clouded lenses dramatically improves glare and halo issues while enhancing overall light tolerance.
Nutritional supplements: Science has identified several natural compounds that appear to reduce glare and halo symptoms. These compounds have been shown to filter damaging short-wavelength visible light from reaching delicate photoreceptors; accelerate glare recovery; promote lens clarity; support retinal health; replenish macular pigment; and manage dry eye symptoms that can worsen visual glare.