Pituitary Adenomas and Your Vision

Pituitary adenomas are tumors that can affect vision, sometimes causing vision loss. As they grow in size, pituitary adenomas can put pressure on important structures in the body, such as the optic nerve. Putting pressure on the optic nerve may cause blindness, so it is crucial for eye doctors to detect pituitary tumors before they cause damage to vision.

The pituitary gland is about the size of a bean and is attached to the base of the brain behind the nasal area. Although small, the pituitary controls the secretion of many different types of hormones. It helps maintain growth and development and regulates many different glands, organs, and hormones. Changes in hormones can cause significant changes in our bodies.

The most common structures that a pituitary tumor compresses are the optic nerve and optic chiasm. The optic nerve is the nerve cable that connects the eye to the brain. The optic chiasm is the point at which the two optic nerves cross. Optic nerve compression causes a gradual loss of vision or a loss of peripheral vision. Loss of peripheral vision in the temporal or side area of our visual field is called a bitemporal hemianopsia.

Besides vision changes such as double vision, drooping eyelids, and visual field loss, pituitary adenomas also may cause the following symptoms:

• Forehead headaches
• Nausea or vomiting
• Change in sense of smell
• Sexual dysfunction
• Depression
• Unexplained weight changes
• Change in menses or early menopause

Because of their effects on vision, eye doctors may be the first to diagnose a pituitary adenoma. To measure the extent of vision loss, eye doctors usually order a computerized visual field test. Because some pituitary tumors can cause hormonal changes, a complete medical history is also taken. The doctor may then order blood and urine testing, as well as magnetic resonance imaging (MRI).

Pituitary adenomas are often treated with neurosurgery to remove the tumor. Radiation therapy using x-rays and proton beams are also used to kill tumors. Medications may first be prescribed to help shrink the tumor.

Early detection of pituitary adenoma is extremely important because of the risk of blindness associated with these tumors. Since your eye doctor is capable of diagnosing pituitary adenoma, see your eye doctor annually.