Light sensitivity is the term used to describe an intolerance of light—this can be from natural sources or artificial causes like fluorescent lights. If an individual suffers from an eye disease, they may be more sensitive to light than those without compromised vision. Light sensitivity can present as glare, and reduced visual performance and discomfort may result from glare. What causes glare, and how can you prevent glare and reduce sensitivity to light?
Glare is a reduction in vision caused by a light source, like the sun or bright lights, or from reflections of light like from water, snow, or windshields. Light scatter—or the spread of light before it reaches the retina to produce an image—is among the many causes of the visual sensation of glare. There are two types of glare, known as discomfort glare and disability glare.
Discomfort glare is a feeling of discomfort in response to a strong light source. This can occur on a sunny day, or due to harsh overhead lighting. Discomfort glare may cause watery eyes, squinting, or looking away from the light source.
Disability glare is reduced visual performance or loss of vision in response to light sources, such as the inability to see well while driving into the sunset or looking at oncoming headlights. In sensitive individuals, even small amounts of light may reduce contrast or vision causing disability glare in what others may consider a comfortable amount of light.
Some are more sensitive to light than others, and the threshold of light sensitivity varies from person to person. Eye conditions such as cataracts, macular degeneration, and inflammation or irritation in the eye, as well as autoimmune disorders and chronic illnesses can cause increased sensitivity to light and glare. If the onset of sensitivity is sudden, a serious medical concern such as meningitis may be the cause and a doctor should be consulted.
Migraine sufferers tend to be more sensitive to light during a migraine headache, and to a lesser degree at other times. Changes in eyes due to aging can also cause increased glare or light sensitivity. Photophobia, defined as an extreme sensitivity when exposed to light, may be related to eye concerns, non-eye-related medical or neurological conditions, or may be associated with prescription or illegal drug use.
Additionally, those with light colored eyes such as blue or green may be more sensitive to light than people with dark eyes. Eye color is determined by how much melanin is present, the same pigment that is responsible for skin color. Melanin protects both skin and eyes from the sun—less melanin means less protection against the sun. Light colored eyes have little to no melanin, so they may be more sensitive to light.
Light sensitivity and glare not related to eye health can be reduced with some simple steps:
Wear UV protective sunglasses.
Polarized sunglasses can further reduce glare on the water or while driving.
Photochromic, or light adaptive, sunglasses can darken in response to the light conditions.
Wrap around sunglasses cover more eye area, which blocks harsh light more effectively.
Put on a wide-brimmed hat to block overhead light.
While driving, a car’s visor can block some glare.
Decrease reflective glare from windows and surfaces with shades, curtains, etc.
An anti-reflective lens coating is an effective way to reduce glare from a computer screen or while driving.
Though adjusting the light level for comfort may cut glare, individuals with higher sensitivity to light may benefit from wearing sunglasses even inside.
While not all light sensitivity can be fixed, treating an underlying medical condition may help reduce the distress associated with glare. A consultation with a low vision specialist can help in coping with glare and the decreased contrast that may result. Additionally, an eye doctor can make recommendations for treatments to reduce glare and sensitivity caused by an eye condition. These recommendations may include cataract surgery or other procedures for eye diseases. Prescription sunglasses, special tinted or light-filtering lenses, or special lighting in the home or office may also reduce glare and provide relief from light sensitivity.
While most people have experienced inconvenience related to glare, it can be a serious concern for those who are light sensitive or suffer from photophobia. If you encounter light sensitivity or glare, have your eyes checked by an optometrist or ophthalmologist for advice and to rule out a serious underlying cause—especially if it came on abruptly. If the sensitivity is not related to an eye condition, you can take measures to reduce discomfort related to glare.