Many people instinctively rub their eyes for relief, prompting questions about the long-term effects on vision. This article clarifies the connection between eye rubbing and astigmatism.
Understanding Astigmatism
Astigmatism is a refractive error, meaning it is an imperfection in how the eye focuses light. This condition arises when the eye’s cornea, the clear front surface, or the lens inside the eye has mismatched curves. Instead of being perfectly round like a basketball, the affected eye takes on an egg or oval shape, similar to a North American football. This irregular curvature prevents light rays from bending properly as they enter the eye, causing them to focus at multiple points instead of a single, sharp point on the retina. The result is blurry or distorted vision at all distances, both near and far.
Eye Rubbing and Astigmatism
For most individuals, rubbing the eyes does not directly cause astigmatism. Chronic and vigorous eye rubbing can, however, worsen or accelerate the progression of an existing condition called keratoconus. Keratoconus involves the progressive thinning and bulging of the cornea into a cone-like shape, which severely distorts vision and induces irregular astigmatism. While not a direct cause of typical astigmatism, eye rubbing is a recognized risk factor for the development and progression of keratoconus, especially in those with genetic predispositions. The mechanical trauma from rubbing can weaken the cornea’s collagen fibers and reduce keratocyte density, contributing to this shape change.
Common Causes of Astigmatism
Astigmatism primarily results from factors unrelated to eye rubbing. Genetics play a significant role, as the condition is often inherited and can be present at birth. Natural eye development and growth can also lead to changes in corneal or lens curvature over time. Astigmatism can also develop or worsen following an eye injury that alters the cornea’s shape. Certain eye diseases or complications from eye surgery can similarly affect the eye’s curvature, leading to astigmatism.
Other Risks of Eye Rubbing
Even without causing astigmatism directly, eye rubbing carries several other potential risks to eye health. Hands frequently carry bacteria, and rubbing the eyes can easily transfer these microorganisms, leading to infections such as conjunctivitis, commonly known as pink eye. The friction and pressure from rubbing can irritate the eyes, resulting in redness and swelling. Delicate blood vessels on the eye’s surface can rupture from vigorous rubbing, causing bloodshot eyes or visible dark circles beneath the eyes.
Direct contact with the eye can also cause corneal abrasions, which are painful scratches on the clear front surface of the eye. For individuals with dry eye syndrome, rubbing can exacerbate symptoms by disrupting the tear film that keeps the eye moist. In people with certain pre-existing conditions like progressive myopia or glaucoma, eye rubbing can increase intraocular pressure, potentially worsening vision or causing nerve damage. The repeated stretching of delicate skin around the eyes from chronic rubbing can also contribute to the loosening of collagen bonds, leading to droopy eyelids and fine lines over time.
When to Consult an Eye Doctor
It is advisable to consult an eye doctor if you experience persistent blurry or distorted vision, as these can be signs of astigmatism or other vision problems. Any intense or ongoing eye pain, or persistent irritation and redness, warrants professional evaluation. Sudden changes in vision, such as new flashes of light, floaters, double vision, or shadows, should prompt immediate attention. Difficulty seeing clearly at night or experiencing significant eye strain and fatigue are also indicators that a comprehensive eye examination is beneficial. Regular eye check-ups are recommended every one to two years to monitor eye health and detect potential issues early.