More rarely, it occurs following a sudden increase in pressure in the eye.
This is a medical emergency. It causes extreme eye pain and other noticeable symptoms, such as loss of vision and colored halos around lights.
Intraocular pressure sometimes rises to 80 mmHg.
Usually, such attacks occur in the evening when the lighting is dim and the pupils dilate.
If this type of glaucoma is not treated promptly, the person can become blind. If it is treated in time, the risk of blindness is greatly reduced.
Narrow-angle glaucoma usually attacks one eye first and can then spread to the other if not properly monitored and preventatively treated.
Two factors are required for a crisis to occur:
- an anatomical predisposition: narrow iridocorneal angle
- dilation of the pupil (the central opening of the iris, where light rays pass): following a long stay in the dark, stress or the use of a medication that dilates the pupil, such as antispasmodics, antihistamines, antidepressants and nitrates.
