Serious side effects of Xalatan that can require professional assistance are photo-sensitivity, excessive discharge from the eye, vision impairments, eye swelling, pain, pronounced redness, itching, or pain in the chest area. Side effects that are milder may include the following reactions: headaches, slight irritation, blurriness, dry eyes, watery eyes, a stinging sensation, or the feeling that a foreign object is in the eye. Any symptoms of an allergic reaction should be reported as soon as possible to your local doctor.