Glaucoma treatment often starts with medicated eye drops. Be sure to use the drops exactly as prescribed; otherwise, your optic nerve damage could get even worse. If your doctor prescribes more than one type of eye drop, make sure to ask how long to wait between applications. To minimize this absorption, close your eyes for one to two minutes after putting the drops in. Press lightly at the corner of your eye near your nose to close the tear duct, and wipe off any unused drops from your eyelid. Multiple drugs are available. The most popular are the prostaglandin analogs. Other drugs include selective adrenergic agonists, cholinergic agonists, and carbonic anhydrase inhibitors. Oral carbonic anhydrase inhibitors are effective, but adverse effects limit their use. Patients taking topical glaucoma drugs should be taught passive lid closure with punctual occlusion to help reduce systemic absorption and associated adverse effects, although the effectiveness of these maneuvers is controversial. Patients who have difficulty instilling drops directly onto the conjunctiva may place the drop on the nose just medial to the medial cantus, and then roll the head slightly toward the eye so that the liquid flows into the eye.