The defective iris severely impairs patients’ vision because the natural iris is missing.
In the healthy eye, the iris controls the incidence of light by adjusting the pupil diameter to the light conditions: the brighter it is, the tighter the pupil contracts. In this way, contrasts between light and dark objects in the room can be easily perceived. Like a camera, the pupil also affects the depth of field, the area in which objects near and a little farther away are seen sharply at the same time.
If the iris is missing, light can enter the eye almost unhindered. Patients affected by the condition perceive strong glare even in normal daylight and are very sensitive to light. In addition, contrasts are less noticeable and depth of field is reduced.
A defective iris is also a cosmetic impairment that can negatively affect the personal appearance as well as their quality of life. Other people may be disturbed by a deformed or missing iris.