Blog 1: Patient-Friendly Version: Pituitary Tumors and Your Eyes: What Patients Should Know
The pituitary gland is a small gland located at the base of the brain, right behind the eyes. Even though it is tiny, it controls many important hormones in the body. Sometimes, a growth can develop in or near this gland. This is called a pituitary tumor.
The good news is that most pituitary tumors are benign, meaning they are not cancer. The American Cancer Society notes that more than 15,000 pituitary tumors are diagnosed each year in the United States, and almost all are benign pituitary adenomas.
How Common Are Pituitary Tumors?
Pituitary tumors are more common than many people realize. Some are discovered because they cause symptoms, while others are found by accident during an MRI or CT scan done for another reason.
Studies suggest that small pituitary adenomas may be found in a noticeable percentage of people when looking at autopsy or imaging studies, even though many never caused symptoms during life. One large review estimated pituitary adenomas may be present in about 16.7% of people when combining autopsy and radiology studies.
That does not mean everyone with a small pituitary tumor is in danger. Many are small, slow-growing, and never affect vision or hormones.
How Can a Pituitary Tumor Affect Vision?
The pituitary gland sits close to the optic chiasm, where the optic nerves from both eyes cross. If a pituitary tumor grows upward, it can press on this area.
This can cause a classic vision problem called bitemporal visual field loss.
That means a person may lose part of their side vision in both eyes. Patients may notice:
Bumping into objects on either side
Trouble seeing cars or people coming from the side
Difficulty reading or scanning a room
A feeling that vision is “off,” even if central vision seems clear
Headaches with vision changes
In early cases, patients may not notice anything at all. That is why visual field testing can be so important.
Other Symptoms of a Pituitary Tumor
Because the pituitary gland controls hormones, symptoms may also include:
Headaches
Fatigue
Unexplained weight changes
Menstrual changes
Infertility
Low sex drive
Breast milk production when not pregnant or breastfeeding
Changes in hand, foot, or facial size
Excessive thirst or urination
Some pituitary tumors make extra hormones, while others do not. Some simply grow large enough to press on nearby structures.
How Eye Doctors Can Help Detect Pituitary Tumors
During an eye exam, your optometrist may check:
Visual acuity
Pupils
Eye movement
Optic nerve appearance
Visual field testing
OCT imaging of the optic nerve and retinal nerve fiber layer
A pituitary tumor may not always be visible just by looking inside the eye. In many cases, the key finding is an abnormal visual field test, especially one showing loss of side vision in both eyes.
When Should You Be Concerned?
You should seek medical care promptly if you have:
New or worsening side vision loss
Persistent headaches with vision changes
Double vision
Drooping eyelid
Sudden severe headache
Sudden vision loss
Nausea, vomiting, or confusion with headache
A sudden severe headache with vision loss can rarely be a sign of pituitary apoplexy, which is bleeding or loss of blood supply within a pituitary tumor. This is a medical emergency.
How Are Pituitary Tumors Treated?
Treatment depends on the type and size of the tumor. Options may include:
Monitoring with repeat MRI scans
Bloodwork to check hormone levels
Medication, especially for prolactin-producing tumors
Surgery
Radiation in select cases
Many patients are managed by a team that may include an endocrinologist, neurosurgeon, ophthalmologist, and optometrist.
Key Takeaway
Pituitary tumors are often benign, but they can affect vision when they grow near the optic nerves. A comprehensive eye exam, especially with visual field testing, can help detect patterns of vision loss that may point to a problem near the brain rather than inside the eye itself.
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