Acute glaucoma is when the pressure inside the eye goes up suddenly. This usually occurs because of a sudden closure of the drainage “angle” inside the eye. With no drainage, the aqueous humor fluid builds up and causes a spike in eye pressure that can lead to rapid vision loss. Symptoms include extreme eye pain along with nausea and halos seen around lights. Treatment is geared toward lowering the pressure and “breaking the attack,” often with a laser, eye drops, and diuretic pills like Diamox. Acute glaucoma is less common in the USA as most people with glaucoma have chronic “open-angle” glaucoma. If an eye appears to be at risk for having an attack, then we will sometimes perform a prophylactic laser procedure called a laser peripheral iridotomy (LPI) to decrease the likelihood of this problem.