Light in your eyes
MONICA CHAUDHRY
| Glare is a common cause of visual discomfort. |
Require protection: Some lenses adjust to the level of light.
Light is essential to vision but too much light or too little light diminishes quality of vision. One of the key factors that affect the quality of vision is glare.
Glare affects the ability of the eyes to distinguish the borders and details near the source of the light. It reduces contrast (the ability to see an object in its background clearly) and also alters perception of colour and shape.
The potential results of glare are squinting, headaches, eye fatigue and, in extreme cases, temporary blindness. As a result, it can be distracting and dangerous.
Four types
There are four types of glare that can impair the visual quality in our daily life: distracting, discomforting, disabling and blinding or reflected. Distracting glare normally comes from car headlights or streetlights at night causing eye fatigue and annoyance.
Discomforting glare emerges from bright sunlight. It can occur, depending upon one's sensitivity, in any weather, at any time of day, in any level or intensity of light, or going from one lighting condition to another. It can bring on squinting and eye fatigue.
Disabling glare occurs as a result of exposure to excessive, intense light, such as that experienced when facing the sun. It can block vision, because it results in reduced contrast of the retinal image.
Blinding or reflected glare comes from light reflected off smooth, shiny surfaces such as water, sand, or snow. It can be strong enough to block vision.
Protection
Most of us are likely to be affected by glare in some form or the other and so require protection. While choosing spectacles, it is important to ensure that the lens material provides protection from glare.
Eye examinations normally happen in a controlled environment in the absence of external factors that can affect vision. In reality one is subject to varying light conditions that affect the quality of vision. Choosing spectacles with the right lens enhancements is critical to ensuring visual quality.
Good quality sunglasses and photochromic lenses (variable tint lenses) provide protection from both harmful UV radiation and glare. Photochromic lenses automatically adjust to the level of light they are exposed to, going from exceptionally clear indoors to comfortably dark outdoors.
They are the best solution for the discomforting, disabling and the distracting glare as they can be worn indoors as well as outdoors. Photochromic lenses with an anti-reflective coating enhance visual quality and comfort by improving contrast and reducing squinting and eye fatigue.
The writer is a Senior Optometrist based in New Delhi.
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