What should be included in a “baseline” eye examination?
- Visual acuity (“center vision”)
- Visual field (“peripheral or side vision”)
- Pupil exam (“the black part of the eye”)
- Slit Lamp exam (exam of the structures of the “front part of the eye”)
- Motility exam (“how the eye moves”)
- Dilated fundus exam (“looking at the back of the eye including the optic nerve”)
What symptoms will the patient have?
- Unexplained usually painless decreased visual acuity or visual field-common
- Double vision (diplopia)-less common
- Droopy eyelid (ptosis)-less common
Why should every patient with a pituitary adenoma have an eye exam?
- Visual loss may be the presenting and only sign of pituitary tumor
- Visual improvement may indicate treatment response of pituitary tumor
- Progressive visual loss may indicate recurrence of tumor
- Baseline ophthalmologic exam
What is the eye doctor looking for?
- Decreased visual acuity or visual field
- Abnormalities in the response of the pupil
- Abnormal eye movements
- Optic atrophy (visible damage to the optic nerve)
How does a pituitary adenoma decrease vision?
- Pituitary tumors (and other types of brain tumors) can cause visual loss by pressure (compression) of the visual pathway
- Depending on where the tumor is located the vision loss may be in one or both eyes and may affect central vision or side vision
How does a pituitary tumor cause double vision?
- Compression of the nerves that control eye movement (ocular motor nerves or cranial nerves III, IV, and VI)
- Loss of vision can cause loss of the ability to keep the eyes aligned (fusion)
How does pressure on the anterior visual pathway cause visual loss?
- Pressure on the optic nerve causes loss of vision in the ipsilateral (“same side”) eye
- Pressure on the optic chiasm causes a bitemporal hemianopsia (“loss of temporal side vision in each eye”)
- Pressure on the optic tract causes a homonymous hemianopsia (Homo: same, Hemi: half, Opsia: loss of vision)
What factors make it more or less likely that the patient with visual loss due to a pituitary tumor will recover vision?
- Age (younger patients do better)
- Vasculopathic risk factors: patients without hypertension, diabetes or other medical problems do better
- Duration of visual loss (the longer the symptoms have been present, the less likely the vision will return
- Presence of optic atrophy (optic atrophy implies some component of irreversible visual loss)
What is the anatomy of the visual pathway?
- Visual information passes through the cornea (the clear part of the eye), the lens, to the retina (like film in a camera) and to the optic nerve, optic chiasm (a crossing point), then to the optic radiations and the occipital cortex
- Pituitary adenomas affect the anterior (or front part of the brain) visual pathway
Is the visual loss reversible after treatment?
- If the pressure on the visual pathway can be relieved most patients experience improvement in vision after treatment
How often should I see the eye doctor?
- Preoperative baseline
- Postoperative baseline
- Postoperative 3 months
- Postoperative 9-12 months
- Yearly if stable
When should I call my eye doctor?
- Blurry central or side vision
- Double vision
- Droopy eyelid
One additional note
- Persons with Cushing’s should also be checked for cataracts since long term exposure to cortisol increases your chances of cataracts.
Author: Dr. Andrew Lee, MD (Spring, ’98)
Editor’s Note: Dr. Andrew G. Lee, MD, Baylor College of Medicine, Division of Neurosurgery, MD Anderson Cancer Center, University of Texas, Neuro-ophthalmology Unit, Department of Ophthalmology, Neurology and Neurosurgery, Baylor College of Medicine, Division of Neurosurgery, MD Anderson Cancer Center, University of Texas