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Understanding Corneal Diseases & Disorders

Corneal disease refers to several conditions that affect the cornea. These include degeneration, infections, and other disorders that are hereditary. Corneal disease is a severe condition that can cause distortion, clouding, tearing, pain decreased/reduced sharpness of vision (vision acuity), and eventually blindness. There are several types of corneal diseases and disorders and some are mentioned below.

Herpes zoster (shingles)

Herpes zoster is the recurrence of the chickenpox virus in individuals who have suffered from the disease before. After a chickenpox attack, this virus always remains dormant in the nerves of the body. It may later move down these nerves, causing infection in specific parts of the body, like the eye. It can cause blisters on the cornea, pain from the affected nerve fibers, and fever.

Corneal blisters always heal by themselves, but antiviral treatment might shorten the disease’s course. Some individuals may develop chronic inflammation of the cornea after suffering from shingles that require the use of long-term eye drops, or corneal surgery, though it’s not common.

Shingles can affect anyone that is exposed to the chickenpox virus, but there’s a high risk in older adults (mostly those over 65 years) and individuals whose immune system is weak. It is advisable to see an ophthalmologist if you have any symptoms of herpes zoster near or in the eye.

Keratoconus

Keratoconus is a continuous disease where the cornea thins and changes shape. Keratoconus switches the curvature of the cornea, creating either severe or mild distortion, known as irregular astigmatism and normally nearsightedness. It can also cause scarring and swelling of the cornea and vision loss.

Causes are genetics, eye trauma, eye diseases like retinopathy of prematurity, retinitis pigmentosa, allergic conditions like eczema, hay fever, and vernal keratoconjunctivitis. Other diseases are osteogenesis imperfect, Down syndrome, etc. In the beginning, the condition is correctable with soft contact lenses or glasses, but as the disease develops, you may be required to put on rigid gas permeable contact lenses.

Corneal transplantation might also be important; the injured cornea is replaced with a donated cornea during the procedure. The contact lenses/ glasses are most likely to be required to see clearly. Corneal crosslinking is a current treatment for keratoconus that uses a special form of ultraviolet light to riboflavin eye drops put on the cornea.

Fuch’s dystrophy

Fuch’s dystrophy is a slow deterioration of the innermost layer of the cornea. This layer serves as a fluid pump to eradicate excess water from the cornea, maintaining the clarity of the cornea. The cornea might swell if these cells weaken with time, therefore, causing blurred vision.

In the advanced phases of this condition, small blisters and haze on the corneal surface may appear, causing irritation and pain. The early signs of Fuch’s dystrophy may be seen in patients in their 30s and 40s. However, the disease normally doesn’t affect vision until about 20 years later.

It is more common among women than men. Some patients with the condition experience blurred vision in the morning and it clears up slowly during the day. As the disease becomes serious, swelling becomes consistent, and vision might be blurry always.

Treatment includes eye drops and ointment for mildly symptomatic patients, observation for the first stages of the disease, Corneal transplant surgery when the vision is notably impaired or when there is chronic pain, and more. In this type of corneal transplant, only the inner lining of the cornea requires a transplant to restore vision.

Vision recovery occurs quicker in contrast to a full-thickness corneal transplant. These procedures are Descemet’s stripping endothelial keratoplasty (DSEK) and (Descemet’s membrane endothelial keratoplasty) (DMEK).

Lattice dystrophy is marked by the presence of unusual protein threads throughout the stoma. Though this condition might occur at any age, early variations can be visible in childhood. It makes clear overlapping protein lines in the stroma. This might make the cornea have clouded and reduced vision. In some individuals, these proteins may lead to epithelial erosion.

Treatment includes ointment or eye drops for symptomatic irritation and corneal transplant for chronic pain, or serious vision loss. Lattice dystrophy may recur in transplant patients who need long-term treatment despite the first results being good.

Keratitis

Keratitis is the corneal inflammation that occurs with infection after fungi or bacteria enter the cornea. These microorganisms might get into the eye after a deep injury, causing inflammation, infection, and ulceration of the cornea.

It is not common, but this type of infection might also occur after an injury from wearing contact lenses. Its symptoms include reduced visual clarity, severe pain, light sensitivity, and corneal discharge. Treatment usually includes antifungal or antibiotic eye drops.

You can read more on corneal ulcers to understand the disease better.

Corneal diseases and disorders are very serious conditions that one must be cautious about because they might lead to loss of vision. You should book an appointment to see an ophthalmologist if you experience any of the symptoms mentioned above.

The ophthalmologist usually uses a slit lamp, an instrument that allows a doctor to check the eye under high magnification. It is often used to check the cornea for infection.