Contact lenses work in the same way as glasses do to correct vision. They redirect light that enters the eye so that it focuses correctly onto the retina. Many people prefer contacts to glasses because of the convenience of not carrying glasses around and because they believe they look better without glasses on. Contacts do require regular maintenance to keep them working properly. If your contacts don't fit correctly, mild or serious symptoms will likely result.
A contact that doesn't fit correctly is likely to irritate the eyeball and the tissue of the eyelid. This irritation can lead to pain and inflammation. There are numerous nerves in the eye and it is very sensitive to stimuli, which is one reason why proper-fitting contact lenses are so important. If a contact is causing pain, it could actually be scratching the surface of the eye, and permanent damage is a possibility. A contact lens needs to be removed as soon as possible the second there is pain associated with it, and it should not be used again until it has been examined by an eye professional.
The irritation caused by a poor-fitting contact lens causes the blood vessels to widen. This allows more blood to flow through and sweep away damaged cells so the eye and surrounding tissue can heal. This inflammation results in redness both in and around the eye. The severity of the redness varies depending on the individual and on the severity of the eye irritation. A contact should be removed even if mild redness is noticed because that is always indicative of eye irritation, and the contact is the likely cause of it.
Loss of Visual Acutity
If a contact is not fitting properly, it may not refract light to the retina properly anymore and as a result, your vision while wearing the contacts will be negatively affected. Continuing to wear the contacts in this condition can result in eye trauma and also cause permanent vision damage to the cornea, which can warp due to frequent use of misfitting contact lenses. Contacts should be removed whenever visual disruptions occur so that both the lenses and your eyes can be checked for damage and the cause of the problem can be treated.