Sudden vision loss in one eye needs same-day evaluation. If it is accompanied by a new headache, scalp tenderness, jaw pain when chewing, fever, or aching in the shoulders and hips, go to an emergency department — these can be signs of giant cell arteritis, which is treatable and which threatens the other eye within days if it is missed.
What it is
The optic nerve carries every visual signal from the eye to the brain, and it depends on a delicate network of very small arteries for its blood supply. When that supply is interrupted, the nerve head swells and the fibers within it are injured — an ischemic optic neuropathy. Because the damage is to the nerve rather than the retina, the eye itself often looks normal apart from swelling of the optic disc.
Two forms — and why the difference matters
Non-arteritic ischemic optic neuropathy (NAION) is by far the more common form. It occurs in people typically over fifty who have a structurally “crowded” optic nerve — a small disc with little room for the fibers passing through it. Vascular risk factors contribute: high blood pressure, diabetes, high cholesterol, and particularly obstructive sleep apnea and episodes of low blood pressure overnight. Patients characteristically wake up having lost vision.
Arteritic ischemic optic neuropathy is caused by giant cell arteritis, an inflammation of medium-sized arteries that occurs almost exclusively after age fifty and becomes more common with each decade. It is much less common than NAION but far more dangerous, because untreated it frequently takes the second eye within days to weeks. It is a medical emergency, and it is treatable with high-dose steroids started immediately.
Distinguishing the two is the central task of the initial evaluation.
Symptoms
- Sudden, painless loss of vision in one eye, frequently noticed on waking
- Loss of the upper or lower half of the visual field, with a sharp horizontal edge
- Dimming of vision, or colors appearing faded and washed out
- In the arteritic form, vision loss is often more profound, and may have been preceded by brief episodes of vision blacking out and returning
Warning signs of giant cell arteritis
Tell us or the emergency physician immediately if you have any of these along with vision loss:
- New headache, especially over the temples
- Tenderness of the scalp — painful to comb hair or rest the head on a pillow
- Aching or fatigue in the jaw while chewing
- Fever, night sweats, loss of appetite, or unintended weight loss
- Aching and stiffness in the shoulders, neck, or hips
- Double vision or a brief total loss of vision that came back
How we evaluate it
Examination shows a swollen optic disc and a relative afferent pupillary defect — an asymmetry in how the pupils respond to light that confirms the nerve is not conducting normally. We check visual acuity, color vision, and visual fields, and OCT imaging is used to measure the swelling and, later, the thinning that follows.
When giant cell arteritis is a possibility, urgent blood tests (ESR, CRP, and a platelet count) are drawn the same day, and a temporal artery biopsy is arranged. Steroid treatment is started before the biopsy result comes back — the biopsy remains informative for a period after treatment begins, and waiting risks the other eye.
Treatment and outlook
For the arteritic form, high-dose corticosteroids are started immediately and continued under the care of a rheumatologist, usually tapered slowly over many months. Steroids rarely restore vision already lost, but they are highly effective at protecting the fellow eye, which is the goal.
For NAION, there is no treatment of proven benefit that reverses the damage. Vision typically stabilizes over weeks, and a minority of patients see modest spontaneous improvement over the following months. The optic disc swelling settles and is replaced by pallor. What remains is usually a fixed area of field loss, often in the lower half.
Protecting the other eye
The most productive conversation after NAION is about the fellow eye, which carries a meaningful risk over the following years. That means being evaluated and treated for obstructive sleep apnea — a strong and modifiable association — and reviewing blood pressure medications with your physician, since drops in blood pressure overnight are thought to contribute. Taking blood pressure medication at bedtime, and use of erectile dysfunction medications, are both worth raising with the prescribing physician. Diabetes and cholesterol should be well controlled, and smoking stopped.
We coordinate with your primary care physician and, when appropriate, with neuro-ophthalmology, and we will follow you to document the field loss and to watch the other eye.