Squinting, the act of partially closing your eyes to see objects more clearly, is something everyone does. But it is more common for people who have refractive errors of the eye so that they can improve their eyesight momentarily. Contrary to popular belief, squinting does not damage your eyes or make your vision worse.
This is a common eye health myth. But the truth is, squinting improves your eyesight by altering the shape of your eye and allowing you to focus correctly by decreasing the amount of light entering your eye. The only possible side effect of frequent squinting is a headache from the contraction of your facial muscles.
What Condition(s) Cause People to Squint?
While squinting does not make your vision worse or damage your eyes, it may suggest that you have a refractive error. For this reason, people with refractive errors who are not using or do not have eyeglasses are more likely to squint frequently. Several eye conditions and other conditions that cause people to squint are:
- Too much light
Nearsightedness, or myopia, refers to an eye disorder in which light focuses in front of your retina rather than on it. The result: distant objects appear blurry while close objects appear normal. If you are myopic and are not wearing your glasses, you may squint to help you focus.
Farsightedness, or hyperopia, is an eye condition in which you see distant objects clearly but closer objects appear blurry. Incoming light is focused behind, instead of on, your retina due to insufficient lens accommodation. The most common symptom of hyperopia is eye strain, characterized by frequent squinting.
Astigmatism refers to an imperfection in the curvature of the cornea or lens. It results in blurred or distorted vision at any distance. Other signs and symptoms of astigmatism include eyestrain, squinting and headaches.
Presbyopia, also referred to as reading blur, is insufficient accommodation associated with aging. It worsens the ability to focus clearly on close objects. It occurs because of age-related changes in the lens, including increased hardness and decreased elasticity. It generally affects individuals older than 45 years and may result in blurred vision, difficulty reading, frequent squinting and headaches.
Too Much Light
This is not a medical condition but an environmental condition. Looking into a strong source of light can lead us to squint, which limits the amount of light that can get into your eyes. Examples are looking at someone who is located near a sunrise or sunset. Or if you have a strong floodlight or camera light pointed directly at you. In those cases, you squint to see.
Is Squinting Harmful to Your Vision? Does It Damage It or Make It Worse?
Squinting has no adverse effects on the health of your eyes. This action does not make your vision worse or damage it. This is a popular eye myth that has been debunked.
Squinting represents an attempt to make your pupil smaller to let in less light. It allows you to focus on what you are observing by eliminating the rays of light that enter your eye at an angle. These rays of light would need to be focused on by your faulty cornea and lens.
Pinhole glasses produce the same effect as squinting by restricting the amount of light entering the cornea. Besides the headaches from prolonged contraction of facial muscles, squinting is harmless.
Why Does Squinting Make Your Eyesight Better?
There are two ways through which squinting makes your eyesight better. First, it improves your vision temporarily because it alters the shape of your eyes. Light enters your eye through your pupil and travels to your lens. Your eye muscles change the shape of your lens to focus the light on your retina.
To see fine details more clearly, light has to reach your fovea, a small spot in the middle of your retina made up of photosensitive cones cells (for color vision). Because of refractive errors in the eye, light coming in through your lens may not be adequately focused, leading to vision problems such as blurry vision.
When you squint, you alter the shape of your lens slightly, allowing the light to be focused properly on your fovea. However, the more significant optical principle at work when you squint is the pinhole effect.
Clear vision comes from light rays properly focusing on your retina at the back of your eye. Typically, this is achieved with contact lenses and eyeglasses, which bend light into focus to correct vision.
When you squint, you create a similar effect as looking through a pinhole. You allow only a small amount of focused light rays into your eye as your eyelid covers up the rest. The unfocused light rays from the periphery do not reach your retina, resulting in improved vision.
How to Stop Squinting
If you are frequent squinter, it may indicate a refractive error of the eye that requires a diagnosis from an eye doctor. To If so, you must treat the causative refractive errors.
Management options for refractive errors and eye conditions that cause frequent squinting include eyeglasses, contact lenses, refractive surgery or a combination of the three based on the diagnosis.
Contact lenses and eyeglasses function by substituting your eye lens that focuses light incorrectly so that you will not have to squint frequently. Vision correction is unique to each patient requiring a unique lens type and power to adjust the focal point of the incoming light on the retina.
Surgical options for correcting refractive errors include LASIK, LASEK, PRK and refractive lens exchange.
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Why can people see more clearly when they squint their eyes? (May 2011). University of California, Santa Barbara.
Eyeglasses for Refractive Errors. (July 2019). National Eye Institute.