We see through the cornea, which is the clear outer lens or “windshield” of the eye. Normally, the cornea has a dome shape, like a ball. Sometimes, however, the structure of the cornea is just not strong enough to hold this round shape and the cornea bulges outward like a cone – a condition known as keratoconus.

As the disease progresses, the cone becomes more pronounced, causing vision to become progressively more blurred and distorted.

Because of the cornea’s irregular shape, patients with keratoconus are usually short-sighted with astigmatism that is not fully correctable with glasses. In moderately severe cases rigid gas-permeable contact lens are the best way to correct the vision.

LASIK (Laser-Assisted In Situ Keratomileusis, a procedure that permanently changes the shape of the cornea, the clear covering of the front of the eye, using an excimer laser) is never performed on keratoconus patients and severe cases require a corneal transplant.

Visual loss occurs primarily from irregular astigmatism and myopia, and secondarily from corneal scarring.

Symptoms:

Patients with keratoconus may report the following:

• Multiple unsatisfactory attempts to obtain optimum spectacle correction
• Monocular diplopia or ghost images
• Distortions
• Glare/flare
• Itchy eyes

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It will often appear as a grey to white opaque or translucent area on the normally transparent cornea. Some corneal ulcers may be too small to see without adequate magnification and illumination.

There are a wide variety of causes of corneal ulcers, including infection, physical and chemical trauma, corneal drying and exposure, and contact lens overwear and misuse.

Contact lens wearers are at particular risk and utmost care must be taken to follow good contact lens hygiene when inserting, removing and storing contact lenses. Unless specifically recommended by your ophthalmologist, never ever sleep with contact lenses in your eye.

Corneal ulcers may result in loss of vision or blindness, but most are preventable: With appropriate and timely treatment, the majority of corneal ulcers will improve with minimal adverse effect on vision.

Symptoms:

Patients with a sight-threatening infection of the cornea can suffer:

• Severe pain (not in all cases)
• White spot on the cornea
• Reduced visual acuity
• Light sensitivity
• Discharge
• Red eye
• Tearing

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The most common symptom of corneal erosion is mild to severe pain. The pain may be particularly uncomfortable in the morning upon awakening because the eyes naturally get dry at night, and the eyelid can stick slightly to the epithelium.

If the epithelium is not firmly attached, sometimes opening the lids can cause the epithelium to tear off. Without treatment, your eyes may continue to experience this erosion.

Other symptoms include:

• Watery eyes (particularly on awakening)
• Feeling of something in the eye
• Light sensitivity
• Blurred vision
• Dryness

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