Coloboma can present as an iris coloboma with the traditional appearance to the iris as a chorio-retinal coloboma where the retina in the lower inside corner of the eye is missing. Coloboma affects different parts of the eye like optic nerves, eyelid, macula, and uveal. Medically, Coloboma refers to the absence of normal tissue in the eye since birth.
Uveal coloboma occurs in the iris (the coloured part of the eye). It gives a keyhole look to the iris, usually before the child is born. When the eye develops during the gestation period, there is a seam which contains the blood vessels. This seam must close by the end of the fifth week. If the seam fails to close properly, then uveal coloboma is formed. It can occur in one or both eyes. The uveal coloboma is situated in the inner lower portion of eye.
What causes Uveal Coloboma?
Uveal coloboma is a genetic disorder which is caused by the malfunction of a gene during eye formation of a child inside the womb. There are various factors which are responsible for coloboma. Alcohol consumption 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. There is very little evidence today that can say why coloboma happened to a person in a family where no one else is affected.
What are the symptoms of Uveal Coloboma?
One of the main signs of uveal coloboma is the difference in the eye colour between the two eyes. This is called heterochromia. Another known symptom is the difference in the eye size. Clouding of the lens, nearsightedness, and retinal malformation are some other common symptoms of uveal coloboma.
Other forms of Coloboma
Other types of coloboma include eyelid coloboma, lens coloboma and macular coloboma. Eyelid coloboma is caused when either the upper or the lower eyelid is absent from the eye. It happens during problems caused during eye formation. In lens coloboma, a part of the lens is absent. Macular coloboma refers to the incomplete formation of the centre of the retina, known as the macula.
Treatment of Coloboma
Even though uveal coloboma is a genetic disease, the condition can be treated and improved as a result of innovation in medical science. People suffering from this disease should visit an ophthalmologist 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. Other medical professionals can provide rehabilitation services and genetic counselling to the patients, which can be very helpful in treating uveal coloboma. Patients who want to hide the iris can choose coloured lens to hide the iris or go for surgery to make the pupil round.