Keratoconus is a vision disorder involving the generally round cornea (the front part of the eye) becoming thin and irregularly (cone) shaped. The abnormal shape prevents the light entering the eye from being focused correctly on the retina and causes distortion of vision.
In its earliest stages, keratoconus causes slight blurring and distortion of vision and increased sensitivity to glare and light. These symptoms usually appear in the late teens or late 20s. Keratoconus may progress for 10-20 years and then slow in its progression. Individual eyes may be affected differently. As keratoconus progresses, the cornea bulges more and vision may become more distorted. In a small number of cases, the cornea will swell and cause a sudden and significant decrease in vision. The swelling is due to the strain exerted by the cornea’s protruding cone-like shape which results in development of a tiny crack. The swelling may last for weeks or months as the crack heals and is gradually replaced by scar tissue. If this sudden swelling does occur, the doctor can prescribe eye drops for temporary relief, but there are no medicines that can prevent the disorder from progressing.
Keratoconus is an uncommon condition in which the normally round, dome-like cornea (the clear front window of the eye) becomes thin and develops a cone-like bulge. Keratoconus literally means “cone-shaped cornea.”
The cornea is a very important part of your eye. Light enters the eye through the cornea, which refracts, or focuses, the light rays so that you can see clearly.
With keratoconus, the shape of the cornea is changed, resulting in vision distortment. It can make it difficult to carry out certain activities such as driving, typing on a computer, watching television or reading.
The cause of keratoconus is still not known. Some researchers believe that genetics play a role, since an estimated 10 percent of people with keratoconus also have a family member with the condition.
In addition, keratoconus is associated with:
- An eye injury, too much rubbing of eyes or wearing hard contact lenses for a long time (many years).
- Certain eye diseases, such as retinitis pigmentosa, retinopathy of prematurity and vernal keratoconjunctivitis.
- Systemic diseases, such as Leber’s congenital amaurosis, Ehlers-Danlos syndrome, Down syndrome and osteogenesis imperfecta.
Keratoconus generally affects both eyes, although its symptoms for each eye may be different. Symptoms generally seen to occur in adolescence and may include:
- Blurring of vision
- Distortion of vision
- Increased sensitivity to light
- Mild eye irritation
Progression rate of keratoconus may vary. It will often show slow progression for 10 to 20 years and then suddenly disappear. As the keratoconus progresses, the most common symptoms include:
- Increased blurring and distortion of your vision
- Increased nearsightedness or astigmatism
- Frequent eyeglass prescription changes
- Inability to wear contact lenses
There is a risk of rejection after a cornea transplant, but the risk is much lower than with other organ transplants.
You should not have laser vision correction (such as LASIK) if you have any degree of keratoconus. Corneal topography is done beforehand to rule out people with this condition.
In rare cases, other laser vision correction procedures such as PRK may be safe for people with mild keratoconus.
Occasionally, keratoconus can advance rapidly, with sudden swelling of the cornea and development of corneal scarring. Scar tissue on the cornea causes the cornea to lose its smoothness and clarity. As a result, even more distortion and blurring of vision can occur.
Your ophthalmologist will be able to diagnose keratoconus during a routine eye exam. A slit lamp can be used to diagnose severe cases of keratoconus, but sometimes corneal topography is needed to diagnose the more subtle cases of keratoconus.
Additional tests may be appropriate to determine the shape of cornea. These include:
- Keratometry. In this procedure, a circle of light is focused on the cornea, and the reflection is used to determine the curve of cornea.
- Computerized corneal mapping. This procedure is used to take a picture of cornea and generate a topographical map of eye’s surface.
- Keratoconus treatment often depends on the severity of the keratoconus symptoms. During early stages, vision can be corrected with eyeglasses. As the condition progresses, rigid contacts may need to be worn so that light entering the eye is refracted evenly and vision is not distorted. A person should also refrain from rubbing eyes, as this can aggravate the thin corneal tissue and make symptoms worse.
- Keratoconus can also be treated with Intacs, which are small curved implantable corneal devices that can reshape the cornea. Intacs are FDA approved and can help flatten the steep cornea found in keratoconus.
- Collagen cross-linking is another treatment option for keratoconus but it is not approved by FDA. It uses a special laser and eyedrops to promote “cross-linking” or strengthening of the collagen fibers that make up the cornea. This treatment may flatten or stiffen the cornea, preventing further protrusion.When good vision is no longer possible with other treatments, a corneal transplant may be recommended. This surgery is only necessary in about 10 percent to 20 percent of patients with keratoconus. In a corneal transplant, your ophthalmologist removes the diseased cornea from your eye and replaces it with a healthy donor cornea.
- Slow healing is observed in a transplanted cornea. It can take a year or longer than that to recover good vision after corneal transplantation.
- Transplant of cornea can relieve the symptoms of keratoconus, but it may not provide you with flawless vision; however, of all conditions that require corneal transplants, a lower rejection rate and the best prognosis for clear vision is observed in keratoconus.
- Another type of cornea transplant that is becoming more popular as a treatment for keratoconus is called DALK, or Deep Anterior Lamellar Keratoplasty. With this procedure, only the front and middle layers of the cornea are transplanted. The benefits of this transplant over the “full” cornea transplant is a much faster healing period and less risk of rejection.
Keratoconus treatment in India at Sanjeevan focuses on the oxygenation of the cornea which helps improve its health, regulates the activity of the enzyme proteases and the enzyme aldehyde dehydrogenase which in various studies has been shown to be a major cause of development of Keratoconus. These enzymes are also responsible for the buildup of free radical and oxidizing species in the cornea, hence we use antioxidant supplements to control their activity which helps in stopping the disruption of the regular arrangement of the collagen layers and collagen fibrial orientation. The treatment helps in strengthening the corneal tissue and improves the shape of the cornea.