The cornea, the eye’s transparent cover, refracts light, which enables the eye to see clearly. A healthy cornea is vital to good eyesight, so damage to the cornea can cause pain, sensitivity to light, blurriness, inflammation, headaches and vision loss.
Conditions and diseases harmful to the cornea include:
- Injuries and trauma
- Keratitis, an inflammation of the cornea resulting from an injury, bacteria, viruses, fungi, or parasites. (One form, neurotrophic keratitis, is a rare degenerative disease characterized by corneal numbness, thinning, ulceration and perforation.)
- Dry eye, resulting from the eyes not producing enough tears or tears of subpar quality
- Shingles, herpes and other viruses
- Iridocorneal endothelial syndrome, causing corneal swelling, glaucoma and changes in the iris
- Pterygium, a growth of tissue on the cornea
- Stevens-Johnson syndrome (erythema multiforme major), a serious skin disorder that also causes conjunctivitis, corneal blisters and erosions, holes in the cornea and painful blisters on the eyelids
- Corneal dystrophies (such as keratoconus, lattice corneal dystrophy, map-dot-fingerprint dystrophy and Fuchs’ dystrophy), which cause parts of the cornea to become cloudy starting in childhood
- Allergies and minor scratches
