It is a serious condition that occurs when there is a sudden increase in pressure inside the eye. It is an emergency and if not treated promptly, may result in decreased vision or worse, permanent vision loss.
Follow this link to know- What is the angle of the eye?
Follow this link to know about basic structure of the eye
What leads to the development of acute angle closure?
Normally, the space between the cornea, the iris, and the lens is good enough that when the iris moves, it doesn’t get stuck on the lens. The distance between the iris and the lens is least during the mid- dilated state ( i.e. when the pupil expands- Video 2).
In some eyes when there is not enough space, in the mid dilated state, rarely does the pupil gets stuck on the lens and blocks the fluid behind it. This pushes the iris forward and further blocks the aqueous (fluid inside the eye) drainage. When this occurs, the pressure inside the eye raises acutely and if not treated, will lead to permanent changes in vision.
How will the patient know if that happens?
There will be sudden pain, decreased vision, difficulty seeing the light, redness, colored halos, headache, etc. There may be associated nausea, vomiting, diarrhea, and other gastrointestinal symptoms.
What to do if that happens?
Get an immediate consultation by an ophthalmologist.