Glare, a sensation of discomfort or reduced clarity, arises when bright light overwhelms the eye’s ability to adapt. It can make everyday tasks challenging, from driving at night to reading in a brightly lit room. This common visual phenomenon occurs when light scatters within the eye or reflects off surfaces, interfering with clear vision.
Everyday Reasons for Glare
Many instances of glare are a normal physiological response to challenging light conditions. While the eye functions across various light levels, intense light can cause discomfort and visual interference. For example, direct sunlight, especially at dawn or dusk, can produce significant glare due to its intensity and low angle. Similarly, the powerful beams of oncoming headlights at night can scatter within the eye, temporarily reducing visibility.
Reflective surfaces frequently contribute to everyday glare. Surfaces such as snow, water, or even wet roads can act like mirrors, bouncing a large amount of light directly into the eyes. This reflected light can be particularly disorienting and uncomfortable, making it difficult to discern objects clearly. When viewing a light source in an otherwise dim environment, such as a single lamp in a dark room, the contrast can also enhance the perception of glare. These common situations are typically not signs of an underlying problem but rather a natural reaction of the visual system to environmental stimuli.
Eye Conditions That Cause Glare
While environmental factors are frequent causes of glare, this sensation sometimes points to specific medical conditions affecting the eye. One common culprit is cataracts, where the eye’s natural lens becomes cloudy. This clouding scatters incoming light rather than focusing it cleanly onto the retina, leading to increased glare, particularly noticeable as halos or starbursts around lights at night.
Dry eye syndrome also contributes to glare, characterized by an insufficient or poor-quality tear film covering the eye’s surface. A healthy tear film creates a smooth, clear optical surface; when it is compromised, light can scatter unevenly as it enters the eye. This irregular light refraction results in glare and often accompanies feelings of discomfort, burning, or grittiness. Issues with the cornea, such as abrasions, certain dystrophies, or irregularities like keratoconus, can also distort light entry and cause glare.
Changes to the corneal shape, even those from corrective procedures, can influence glare perception. Individuals may experience temporary or sometimes persistent glare, halos, or starbursts after LASIK or other refractive surgeries. These visual disturbances occur because the altered corneal curvature can cause light to bend differently, leading to light scatter. Glare and increased light sensitivity can also be a symptom of neurological events, such as migraines with aura, where visual disturbances precede or accompany the headache.
When to Consult an Eye Doctor
While occasional glare is normal, certain characteristics warrant professional medical evaluation. A sudden onset of significant glare, especially if it appears without an obvious environmental cause, should prompt a visit to an eye care specialist. If glare is accompanied by other concerning symptoms, such as eye pain, a noticeable decrease in vision, persistent halos around lights, or double vision, it indicates a need for immediate attention.
Persistent glare that interferes with daily activities, such as driving, reading, or working on a computer, also suggests an underlying issue. If the glare seems to be worsening over time, even subtly, it is prudent to seek a comprehensive eye examination. An eye doctor can accurately diagnose the cause of the glare and recommend appropriate treatment, preventing potential progression of an underlying condition.
Tips for Reducing Glare
Managing glare involves practical adjustments and protective measures, irrespective of its cause. Wearing high-quality sunglasses, especially those with polarized lenses, can significantly reduce reflected glare from surfaces like water, snow, and roads. Polarized lenses contain a special filter that blocks horizontally oriented light waves, which are responsible for reflective glare. Applying an anti-glare coating to prescription eyeglasses or sunglasses also helps by reducing reflections off the lens surfaces, allowing more light to pass through clearly.
When using digital devices, adjusting screen brightness to match the ambient lighting and utilizing dark mode settings can help minimize the impact of emitted light. Improving indoor lighting can also reduce glare by ensuring adequate, evenly distributed illumination and avoiding direct, harsh light sources. In vehicles, using the car’s visor can block direct sunlight, and ensuring the windshield is clean can prevent additional light scatter. For mild dry eye that contributes to glare, blinking more frequently or using over-the-counter artificial tears can help maintain a smoother, more consistent tear film on the eye’s surface, improving visual comfort.