Common Complications of Soft Contact Lenses Part II
| Common Complications of Soft Contact Lenses Part II |
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| Date: August 6, 2006 | |
| Blood Vessel Growth Abnormal ingrowth of blood vessels in the cornea, especially at the edges of the cornea (corneal neovascularization) is often due to corneal hypoxia (lack of high permeability to oxygen). It is a common sign associated with soft contact lens wear. The cornea, which normally has no blood vessels, derives its oxygen directly from air and not from the bloodstream. Contact lenses reduce the cornea's ability to derive oxygen. The cornea responds to chronic oxygen deprivation (which can occur during extensive contact lens wear) by growing new, abnormal blood vessels. Sometimes by changing the type of contact lens material or your wearing schedule the new blood vessel growth can be reversed. In some cases you may simply need to stop wearing your lenses completely. Contact lenses are designed to allow an adequate amount of oxygen through the lens. This only works if they are worn properly and evaluated on a regular basis. Many patients try to extend the life of their lenses by wearing a monthly disposable lens for five to six weeks instead of four. Another example would be sleeping in a lens prescribed for daily wear. This cuts the life of the lens in half. At the end of the life of the lens, oxygen does not permeate the lens. This initiates the body to respond to oxygen deprivation by growing new blood vessels into the cornea. This process does not cause pain or discomfort until basically, it's too late. At this point, contact lenses must be discontinued and/or patients develop corneal breakdown or a serious vision threatening infection. Corneal Infections The development of a corneal ulcer (an infection of the cornea) unfortunately, can be a complication of contact lens use. A corneal infection is a localized corneal excavation due to hypoxia and then subsequent epithelial disruption. Although there is a higher incidence of corneal infections associated with soft contact lens wear than rigid lens wear, all lenses have some risk. A corneal ulcer starts when a bacteria infects an area of breakdown in the corneal surface. The surface may break down, forming a small corneal abrasion, due to routine lens use. Normally, a corneal abrasion, even if tiny, is uncomfortable. However, a contact lens can act as a bandage on the eye masking symptoms, and some contact users develop a lack of sensitivity of the cornea. Upon development of a corneal infection, acute pain is felt in conjunction with a foreign body sensation, and the eye typically becoming red and light sensitive. Vision loss is not uncommon. Even with successful treatment, a corneal ulcer may still leave a scar that may affect vision or the ability to resume contact lens wear. Please contact our office with questions concerning these topics at 405-372-1517 in Stillwater or 918-762-2573 in Pawnee. |
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