Uveal Coloboma

Coloboma can affect optic nerves, eyelid, macula, and the uveal

The word “coloboma” is derived from the Greek word “curtailed”. The word “curtailed” is used medically to describe the absence of normal tissue in the eye since birth. Coloboma affects different parts of the eye like optic nerves, eyelid, macula, and uveal. Let’s look at uveal coloboma in greater detail.

Overview of Uveal Coloboma

Uveal coloboma occurs in the iris (the colored part of the eye). It causes a “keyhole” or “cat eye” look to the iris, usually before the child is born. During the gestation period when the eye is forming, there is a seam which contains the blood vessels. This seam must close by the end of the fifth week. If this closure does not take place properly, then uveal coloboma is formed. It can happen in one or both eyes. The uveal coloboma is situated in the inner lower portion of eye.

Causes of Uveal Coloboma

Uveal coloboma is a genetic disorder which is caused by the malfunction of a gene during eye formation. There are a number of factors which cause coloboma. Intake of alcohol during pregnancy may increase the chance of uveal coloboma. In most cases, it is a matter of chance that the gene may not work properly.

Symptoms of Uveal Coloboma

One of the main symptoms of uveal coloboma is the difference in the eye color between the two eyes. This is known as heterochromia. Another obvious symptom is the difference in the eye size (microphthalmia). Clouding of the lens, near sightedness, and retinal malformation are some other common symptoms of uveal coloboma.

Other Types of Coloboma

Some other types of coloboma are eyelid coloboma, lens coloboma, and macular coloboma. Eyelid coloboma is caused when either the upper or the lower eyelid is absent from the eye. Again, it happens due to problems caused during eye formation. In lens coloboma, a part of the lens is absent. Macular coloboma refers to the incomplete formation of the center of the retina, known as the macula.

Treatment of Uveal Coloboma

Even though uveal coloboma is a genetic disease, the condition can be treated and improved as a result of advancement in science and technology. People suffering from this disease should visit an eye specialist at least twice a week. With the use of error lens, the refracting error can be corrected. Using low vision devices can also be helpful. Specialists can provide rehabilitation services and genetic counseling to the patients, which can be very helpful in treating this disorder. For patients who want to hide the iris, they can opt for colored lens to hide the iris or go for surgery to make the pupil round.


According to research, uveal coloboma is caused by incomplete closure of the optic fissure during the 5th week of gestation period. The basic aim of uveal coloboma research is to improve the condition of patients by trying to understand how they see and what difficulties they face. With the help of modern genetic tools and detailed information, scientists and eye specialists are trying to improve the condition of people who are suffering from uveal coloboma.

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