I went to a new eye doctor yesterday and mentioned that I’d had pituitary surgery in 1987. She asked me if I ever had a visual field test and I think I said something like DUH!. No one has ever mentioned this to me even though I’ve been seeing eye doctors forever, long before my Cushing’s.
She said that she sees many(!?!) patients with pituitary tumors and the tumor can cause issues by pressing on the optic chiasm. This was all news to me.
It seems like this would not be an issue all these years later but I think I’m going to do the test anyway.
Has anyone else been tested? What were the results?
Of course I came home and looked this up. Google AI said:
A pituitary tumor, also known as a pituitary adenoma, can cause significant vision problems by compressing the optic chiasm. The optic chiasm is a structure at the base of the brain where the optic nerves from each eye cross and transmit visual information to the brain. A large tumor (macroadenoma) growing upward from the pituitary gland can press on these nerves, disrupting vision.
Symptoms of optic chiasm compression
Visual symptoms often develop gradually, and a person may not notice changes until the vision loss is advanced. Common signs and symptoms include:
- Loss of peripheral vision: The classic symptom is bitemporal hemianopsia, which is the loss of vision on the outer (temporal) side of both visual fields, corresponding to the fibers that cross at the chiasm.
- Blurred vision: A decrease in central visual acuity can occur, especially if the tumor also compresses one of the optic nerves.
- Loss of color vision: A reduced ability to perceive colors (dyschromatopsia) is another possible symptom.
- Headaches: The pressure from a growing tumor on surrounding structures can cause headaches, which are one of the most common symptoms reported by patients.
- Double vision (diplopia): This may occur if the tumor expands laterally and compresses the cranial nerves that control eye movement.
- Pituitary apoplexy: A sudden hemorrhage into the tumor can cause an acute, severe headache and rapid vision loss, which is a medical emergency.
Diagnosis
To determine the extent of optic chiasm compression, a medical team will perform several diagnostic steps:
- Comprehensive eye exam: An ophthalmologist or neuro-ophthalmologist will perform a visual acuity test to measure central vision and a visual field test to map out the entire field of vision.
- Optical coherence tomography (OCT): This imaging technique can measure the thickness of the retinal nerve fiber layer, which helps detect damage to the optic nerve from chronic pressure.
- Neuroimaging: An MRI of the brain with and without contrast is the preferred method to visualize the tumor, confirm its size, and see its proximity to the optic nerves and chiasm.
- Endocrine workup: Blood tests are necessary to check hormone levels, especially for tumors that secrete excess hormones, such as prolactin.
Treatment and prognosis
The treatment for optic chiasm compression depends on the tumor’s size, type, and growth pattern. Early diagnosis and treatment offer the best chance for vision recovery.
- Medication: For prolactin-secreting tumors (prolactinomas), medication such as cabergoline can often shrink the tumor and relieve pressure on the optic chiasm, potentially restoring vision without surgery.
- Surgery: The most common approach for tumors that compress the optic chiasm is surgical resection, often performed through the nose using a minimally invasive transsphenoidal approach.
- Radiation therapy: This may be used as a secondary treatment if surgery is not fully successful, or for tumors that cannot be treated with medication.
- Prognosis: Recovery of vision is common after successful treatment, especially if the compression has not been long-standing. Many patients experience a significant improvement in their visual field. Long-term monitoring with regular MRI scans and visual field tests is necessary to check for tumor regrowth.