Many people with glaucoma need surgery on both eyes. Because vision may be worse right after surgery or complications may develop, both eyes are not operated on at the same time. The following are guidelines that ophthalmologists use to determine which eye needs to be operated on first.

In most cases, the eye with greater vision loss and more advanced glaucoma is treated first.

• If the surgery on the first eye is not successful, the person can still rely on his or her better eye.
• If surgery must be delayed, the better eye will be able to tolerate increases in pressure better than the other eye could.

Occasionally it is better to do surgery on the best eye first. The best eye may be operated on first if:

• The damage in the eye with the worse vision is so advanced that the surgery will not improve the vision, even if the glaucoma is under better control.
• The person does not want to have surgery on both eyes.

The second eye is operated on as soon as the doctor and the person can tell how well surgery on the first eye worked. The time between surgeries varies with the type of surgery done.