WATCH: Dr. Andrew Lee Shares Tips on How to Spot Optic Neuropathy

In his latest educational whiteboard video, Houston Methodist Chief of Ophthalmology Dr. Andrew Lee delivers a concise yet comprehensive overview of how to clinically diagnose optic neuropathy — an essential skill for any eye care provider.

"Optic neuropathy, defined as damage to the optic nerve, can present subtly but has clear clinical hallmarks if you know what to look for," explains Dr. Lee, who specializes in neuro-ophthalmology. "Since the optic nerve acts as the 'cable' transmitting visual information from the retina to the brain, any compromise can manifest as vision loss or field deficits."

To identify the condition, Dr. Lee recommends a structured exam that includes:

• Visual acuity testing — Most optic neuropathies result in decreased central vision.
• Visual field assessment — Defects may be central, arcuate or altitudinal depending on the etiology.
• Swinging flashlight test — A relative afferent pupillary defect (RAPD) is a key objective sign. When light is swung from the unaffected eye to the affected one, the pupil paradoxically dilates instead of constricting. This finding strongly suggests optic nerve dysfunction, especially when the fundus appears normal.
• Fundoscopic exam — The optic nerve may be swollen, pale or normal in appearance.

RAPD in conjunction with vision loss and a normal retina is often the clearest indicator of optic nerve pathology.

"While large retinal lesions can sometimes produce RAPD, it is more commonly associated with optic neuropathy," explains Dr. Lee.

In adults, acute optic neuritis is the leading cause of optic neuropathy in younger patients and typically reflects inflammation. In contrast, anterior ischemic optic neuropathy (AION) is more common in older individuals, particularly those with vascular risk factors like hypertension or diabetes. It is due to impaired blood flow to the optic nerve.

Ultimately, despite recent advances in ophthalmological technology, traditional visual testing, pupil assessment and optic nerve evaluation remain the cornerstones for diagnosing optic neuropathy and guiding appropriate management, according to Dr. Lee.