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People who are far sighted (who have positive prescriptions, those which make the eyes look larger) are at greater risk for glaucoma attacks because their eyes are smaller than average and the iris and the lens is crowded within a smaller space. Angle closure is the result of a ball valve effect. The lens pushes on the pupil causing a partial blockage of the pupillary opening. This causes the pressure of the fluid behind the lens and iris to rise pushing the lens even more forcefully against the pupil, causing even more blockage. If the pupil is partially dilated, as happens at night, the iris becomes more loose and can trigger an attack. Narrow angle glaucoma caused by the anatomy of the eye is called primary open angle glaucoma. Sometimes an injury in the form of a strong blow to the eye can loosen the lens and cause what is called secondary angle closure. A screening eye exam can detect narrow angles before an attack occurs and a simple laser treatment called a peripheral iridectomy (PI) greatly reduces the risk of a future attack. A PI is a small hole in the iris, usually made by a laser.
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If it the disease is caught early, the underlying retinal disease can be treated with laser photocoagulation. This is a procedure where laser is used to make small burns in the peripheral retina which cause abnormal capillaries to shrink by an unknown mechanism. Furthermore, anti-VEGF medications such as Lucentis or Avastin can be injected into the back of the eye. If the IOP has risen significantly and cannot be controlled with medicated drops then glaucoma surgery is necessary. The common trabeculectomy does not work well for this condition because the opening made to drain the eye can become occluded by the capillary sheets. Instead, a valve or tube shunt is usually placed. This consists of a tube which is inserted into the anterior chamber (the front space) of the eye. The tube is connected to a plate which has a flap-like mechanism which forms a valve that controls the IOP.
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