The cornea is the transparent, dome-shaped outer layer of the eye. It provides about two-thirds of the eye’s focusing power by bending light to create a sharp image on the retina. The cornea also serves as a protective barrier, shielding the eye from germs, dust, and other foreign materials.
Protecting Your Corneas
Maintaining the health of your corneas involves several proactive measures. One of the most impactful habits is practicing meticulous contact lens hygiene. This includes washing hands thoroughly before handling lenses, using prescribed disinfecting solutions, and strictly adhering to the replacement schedule to prevent infections. Improper care can lead to serious conditions, including corneal abrasions and ulcers.
The use of protective eyewear is another fundamental aspect of corneal care. During activities such as yard work, woodworking, sports, or handling chemicals, wearing safety glasses or goggles provides a physical barrier against dust, debris, and flying objects that can cause injury.
Protecting your eyes from the sun’s ultraviolet (UV) radiation is also important for long-term corneal health. Sunglasses that block 99-100% of both UVA and UVB rays shield the cornea from damage that can contribute to certain growths and other conditions. For comprehensive protection, wraparound styles are particularly effective at blocking light from all angles.
Finally, managing eye dryness helps maintain a healthy tear film, which is necessary for corneal function. Blinking regularly, especially during prolonged screen use, helps to spread tears evenly across the eye’s surface. Staying well-hydrated and using artificial tears if needed can also alleviate dryness and irritation, ensuring the cornea remains properly lubricated.
Common Corneal Conditions and Symptoms
One of the most frequent injuries is a corneal abrasion, which is a scratch on the eye’s surface. These occur from direct trauma, such as being poked by a fingernail, or from foreign debris like dust or sand getting trapped under the eyelid. Symptoms are immediate and include:
- A sharp pain
- The distinct feeling that something is in the eye
- Significant redness
- Tearing
- Sensitivity to light
Keratitis is the inflammation of the cornea, which can be caused by bacteria, viruses, fungi, or parasites, introduced through improper contact lens wear or an injury. The symptoms can be more severe than a simple abrasion and include:
- Intense pain
- Significant redness
- Blurred or decreased vision
- A pus-like discharge from the eye
This condition requires prompt medical attention to prevent complications.
A corneal ulcer is an open sore on the cornea that develops as a serious complication of an untreated infection, such as keratitis. This condition is a medical emergency, as it can lead to severe scarring and permanent vision loss. Symptoms include:
- Severe eye pain
- Heavy discharge
- A visible white spot on the cornea
- Blurry vision
- Extreme light sensitivity
Medical Diagnosis and Treatment Options
If a corneal problem is suspected, an eye care specialist will conduct a comprehensive eye exam. A key diagnostic tool is the slit-lamp, a microscope that provides a highly magnified view of the eye’s structures. To reveal surface damage like abrasions or ulcers, the doctor may use a special dye called fluorescein, which makes any irregularities on the corneal surface glow green under a blue light.
For infections like keratitis or corneal ulcers, medicated eye drops are a common treatment. These can include antibiotic drops for bacterial infections, antiviral medications for viruses, or antifungal drops for fungal keratitis. In cases of inflammation, steroid eye drops may be prescribed to reduce swelling and prevent scarring.
For certain injuries, such as a large corneal abrasion, a bandage contact lens may be used. This special lens is placed over the cornea to act as a protective shield, which can reduce pain and promote healing by allowing the epithelial cells to regenerate underneath.
In more severe cases where scarring or thinning has permanently affected vision, advanced procedures may be necessary. Corneal cross-linking is a treatment used for conditions like keratoconus, where the cornea weakens and bulges. For extensive damage, a corneal transplant, where the damaged corneal tissue is replaced with healthy donor tissue, may be the only option to restore vision.