Colored contact lenses are a popular way to change your appearance, offering options from subtle enhancements to dramatic costume effects. These lenses are classified as medical devices by the Food and Drug Administration (FDA) in the United States, not simple cosmetic accessories. While colored contacts, including both vision-correcting and purely cosmetic (plano) types, can be worn safely, they carry a risk of causing significant eye damage. This damage occurs almost exclusively when lenses are acquired illegally without oversight or when the wearer disregards established safety and hygiene protocols.
The Necessity of a Proper Prescription
Every type of contact lens, even those with no vision correction power, legally requires a valid prescription from an eye care professional. This federal regulation exists because lenses sit directly on sensitive corneal tissue and must be custom-fitted to the eye’s specific measurements. Lenses purchased without a prescription often come from unauthorized sources, bypassing this essential medical fitting process.
The prescription ensures the lens has the correct base curve and diameter, defining how the lens rests on the eye’s dome-shaped surface. A poorly fitting lens that is too tight can press against the cornea, leading to a painful corneal abrasion (a scratch on the outer layer). An ill-fitting lens can also impede the natural exchange of tears, trapping debris and making the eye susceptible to infection.
Colored lenses are often thicker than clear lenses because the pigment is embedded within the material, reducing the amount of oxygen that reaches the eye. A lens that is not fitted to allow proper movement, combined with reduced oxygen flow, can cause corneal hypoxia (oxygen deprivation). This lack of oxygen stresses the cornea and makes it vulnerable to serious complications.
User Habits That Lead to Eye Injury
Non-compliance with the prescribed care routine is the main factor contributing to eye damage from contact lenses. Microbial keratitis, a severe eye infection, is caused by introducing pathogens to the eye with contaminated lenses. The risk of infection increases significantly when lenses are exposed to non-sterile liquids, such as using tap water or homemade saline solutions for cleaning or storage.
Microorganisms like bacteria, fungi, and the waterborne parasite Acanthamoeba can adhere to the lens surface and multiply if the lenses are not adequately rubbed and rinsed with fresh disinfecting solution. Using expired solution or “topping off” the lens case with old solution instead of replacing it entirely reduces disinfection efficacy. This allows dangerous pathogens to persist on the lens before it is placed onto the eye.
Overwearing lenses, particularly sleeping in them, is the highest risk factor for microbial infection and other complications. When the eyelids are closed and a lens is worn, the cornea’s oxygen supply is drastically reduced, inducing chronic hypoxia. In response to this long-term oxygen deprivation, the eye may attempt to compensate by growing new, abnormal blood vessels into the clear cornea, a condition called neovascularization. These fragile new blood vessels can eventually lead to permanent vision loss if they grow toward the center of vision. Sharing colored contacts is also dangerous, as it instantly transfers bacteria, viruses, and other microorganisms between users.
Identifying Symptoms of Contact Lens Damage
Recognizing the early warning signs of a complication helps prevent permanent damage to the eye. Symptoms suggesting a problem include persistent redness that does not clear up quickly after removing the lens, or significant pain in or around the eye.
Other concerning symptoms include:
- Blurred vision that continues after the lens is removed.
- Unusual sensitivity to light (photophobia).
- Excessive tearing or discharge from the eye.
- A persistent gritty, foreign-body sensation.
If any of these symptoms appear, the contact lenses should be immediately removed and not reinserted. Contact an eye care professional right away, such as an ophthalmologist or optometrist, rather than attempting to self-treat with over-the-counter drops. Serious conditions like corneal ulcers or severe keratitis can progress quickly and may lead to irreversible vision loss if not treated immediately with prescription medication.