Angle Closure Glaucoma
Angle closure glaucoma is type of glaucoma that occur due to closure of the angle between the cornea and the iris. Aqueous humor is secreted behind the iris and flows anteriorly in front of the lens and iris to the angle where it is drained outside the eye through trabecular meshwork to canals of schlemm and then through veins to outside the eye.
For some reasons the angle is closed and the aqueous can not be drained outside the eye, so the secretion of aqueous humor is more than the drainage and the intra-ocular pressure will increase dramatically.
Closed angle glaucoma is considered as medical emergency because it is acute and painful and it can cause rapid and severe damage to cornea, iris, lens and optic nerve. Sometimes the angle closure glaucoma is silent and comes in chronic form.
The angle in those patients are partially closed in which there is restriction in the amount of aqueous that drained.
Symptoms in chronic form will be the same as primary open angle glaucoma but the difference in both can be seen during your ocular examination when your doctor notices that your angle is closed.To be able to see the angle, your doctor will use special lens called gonioscope to view the angle.
Sometimes the attacks can be intermittent and it occurs in patients with narrow but not occluded angle. Those patients are usually with hyperopia in which the length of the eye is shorter than normal and its structures are crowded with narrow angle.
The space between the iris and cornea is small and any cause that can further makes this space smaller will lead to closed angle and high I.O.P but when this cause or stimulus is ended or terminated ,I.O.P will returns to normal.
These attacks occur mainly in darkened rooms or environments like in cinemas and also it can occur when one is excited or anxious, during exercise and with certain medications. These things will cause the pupil to dilate which will push the iris further more on the angle and overcrowd it leading to angle closure. When the stimulus is ended, the pupil will comeback to its normal position and the angle is opened again with I.O.P drops to normal.
There are certain signs can be seen during eye exam which will give a clue about previous attacks of angle closure.
Medications that can cause Pupil Dilation
1- Eye drops used in eye clinics for routine eye exam like Cyclopentolate, Tropicamide and atropine eye drops.
2- Tricyclic antidepressants like as Protriptyline (Vivactil) and Doxepin (Sinequan).
3- Antihistamine medications like Cetirizine (Zyrtec) and Desloratadine (Clarinex).
4- Topiramate (Topamax) which is oral medication used to treat bipolar disorder and migraine.
Symptoms of Angle Closure Glaucoma
1- Severe eye pain.
3- Excessive tearing.
5- Red eye.
6- Sudden drop in vision or blurred vision: sudden drop of vision mainly due to corneal edema initially and lately due to cataract and optic nerve damage.
7- Halos around lights which occur mainly due to corneal edema.
8- Nausea and vomiting.
Types of Angle Closure Glaucoma
Angle closure glaucoma types will be according to the causes and according to the time of onset.
Read more about types of Angle Closure Glaucoma
Narrow Angle Glaucoma
Narrow angle glaucoma is type of angle closure glaucoma. There are anatomical factors in the eye which will cause a narrow or smaller space between the peripheral iris and trabecular meshwork.
Read more about Narrow Angle Glaucoma
As we know that the iris lies infront of the lens and there is small contact between the back surface of the iris with the anterior surface of the lens. The aqueous will flow from the posterior chamber of the eye through this space between the iris and the lens to the anterior chamber..
Read more about Pupillary Block