Wearing contact lenses that are too strong, known as over-correction, means the lens power exceeds what your eye requires to focus light correctly onto the retina. This often happens when a prescription is miscalculated or when a wearer attempts to self-correct their vision with a stronger lens than recommended. Wearing lenses that are significantly too powerful introduces a persistent strain on the visual system. The immediate consequence is not damage, but rather uncomfortable symptoms as your eyes attempt to manage the excess power.
Immediate Signs of Over-Correction
Symptoms of over-correction are typically acute and noticeable soon after the lenses are inserted. A common complaint is a tension headache, frequently felt across the forehead or temples, resulting from the sustained effort of the internal eye muscles. This strain is often accompanied by visual fatigue or “tired eyes,” even after adequate rest.
Users may experience difficulty focusing, especially on objects up close, because the stronger lens power provides too much correction. This forces the eye to work harder to relax its focus for near tasks like reading or looking at a phone screen. Blurred vision can also occur at a distance if the over-correction is significant enough to push the focal point of light past the retina. The visual confusion and muscle strain can sometimes lead to mild, transient feelings of dizziness or nausea as the brain struggles to process the incorrectly focused images.
Understanding Eye Strain from Stronger Lenses
The physiological mechanism behind the discomfort from over-corrected lenses centers on the ciliary muscles, which control the shape of the eye’s lens. When a person wears a lens that is too strong, the lens over-focuses light, making distant objects appear to be focused in front of the retina. To compensate for this excess power, the eye must constantly engage its focusing mechanism, a process called accommodation.
The ciliary muscles must contract to flatten the eye’s natural lens, attempting to relax the focus backward to counteract the strong contact lens. This sustained muscular effort leads to eye strain, or asthenopia, and the associated tension headaches. The eye repeatedly attempts to find the correct focal point, resulting in muscle fatigue. This continuous, forced accommodative state is the body’s attempt to achieve clear vision despite the incorrect prescription.
Addressing Concerns About Permanent Damage
A major concern for anyone experiencing discomfort from an incorrect prescription is whether the over-correction will lead to lasting harm. Wearing contact lenses that are too strong, while highly uncomfortable and fatiguing, generally does not cause permanent structural damage to the adult eye or result in permanent vision loss. The symptoms experienced, such as headaches and eye strain, are a direct result of muscle fatigue and are temporary.
The effects of over-correction are completely reversible. Once the incorrectly powered lenses are removed and replaced with the proper prescription, the ciliary muscles can relax, and the associated symptoms typically resolve quickly. The primary risk associated with contact lenses relates to improper wear or hygiene, which can lead to infection, not to the optical power being slightly off.
What to Do If Your Lenses Are Too Strong
If you suspect your current contact lenses are too strong due to persistent symptoms like headaches, dizziness, or eye fatigue, stop wearing them entirely. Remove the contacts and revert to wearing your most recently used, comfortable pair of eyeglasses or a previous pair of contacts. This action immediately relieves the excessive accommodative demand on your eye muscles.
Contact the eye care professional who issued the prescription. Explain the specific symptoms you are experiencing and how long they have persisted. The doctor will likely schedule a re-examination, specifically a new refraction test, to accurately measure your current vision needs and confirm the degree of over-correction. Never try to adjust your own prescription by choosing a slightly weaker lens without a doctor’s confirmation, as this can lead to an imbalance in your visual system.