The iris is the coloured part of the eye. The iris plays an important role with regard to vision, but it also has another function. The colour of the iris is an important individual facial trait. This is why a damaged or absent iris not only causes a medical problem for the patient due to an excess amount of light entering the eye, but also a psychological problem because the patient has this “strange eye” with a black hole. Although the target group is small, there is a real need here for specialised products. Reason enough for OPHTEC to offer these products.
- The function of the iris
- Vision and iris defects
- Iris disorders
 |
The iris is the coloured part behind the cornea with the pupil at its centre. |
The function of the iris
The iris regulates the amount of light that enters the eye in much the same way as the diaphragm of a camera. The organ consists of muscle tissue and pigment. When the tiny sphincter muscles of the iris contract, they cause the pupil to constrict in response thus reducing the quantity of light that reaches the eye. When the tiny sphincter muscles relax, they cause the pupil to dilate thus allowing more light to reach the retina. The pigment determines eye colour. The more pigment there is in the iris, the darker the eyes.
Iris defects and the acuity of vision
A damaged or congenitally defective iris does not function well which results in poor quality of vision. Too much light enters the eye making it is impossible or very difficult to focus on a given object. It is almost as if you were constantly looking straight into the headlights of an oncoming car: lots of bright light with accompanying glare and halos. Less severe damage, such as small holes in the iris, may cause shadows to occur because the holes allow additional light to reach the retina. These shadows are known as double or phantom images.
Iris disorders
- Aniridia
Aniridia is a rare congenital complex eye disease characterised by an underdeveloped iris. It originates during pregnancy and is caused by a genetic defect.
 |
Aniridia literally means absence of the iris. Sometimes all that is left is a tiny edge of the iris. |
- Iris coloboma
In the case of Iris Coloboma, the iris contains a hole. This may be the result of a genetic defect or an accident.
 |
Iris coloboma If the hole is at the edge, it looks as if the pupil has an abnormal shape. |
- Eye trauma, with damage to the iris
The iris may be damaged in an accident.
• Accidents in which the eyeball is pierced by a sharp pointed object. (glass, knife, bullet, scissors). Such accidents may cause severe damage to the iris.
• Accidents in which the eye is damaged as a result of a hard jab or a blow to the eye. For instance by a small ball, an airbag or fireworks. This may cause the iris to rupture.
