Based on WHO | Can head and neck cancer cause vision problems, and what visual symptoms should I watch for?

Head and neck cancers can affect vision, especially when tumors arise near the sinuses, nasal cavity, or skull base, or when treatments involve these areas. ^[1] Tumors and their treatments can impact the muscles that move the eyes and the optic nerve that carries visual signals to the brain, which may lead to vision problems. ^[1]

Why vision can be affected

• Sinonasal and skull base proximity: Cancers in the nasal cavity and paranasal sinuses share thin bony walls with the orbits (eye sockets), so tumors can invade the orbit and disturb eye movement or optic nerve function. ^[2] Vision changes can occur if the tumor extends to the skull base and presses on nerves controlling eye movement or sight. ^{[3] [4]}
• Nerve involvement (cranial neuropathy): Some head and neck skin cancers (especially squamous cell carcinoma) can spread along nerves (perineural spread), causing eye movement problems (ophthalmoplegia), facial numbness, and even vision loss as the disease reaches the orbital apex or intracranial pathways. ^[5] Painful ophthalmoplegia with progressive blindness has been described when tumor cells spread along the supraorbital nerve to the orbital apex. ^[6]
• Treatment-related effects: Radiation to sinonasal or orbital regions can cause dry eye and vision problems; targeted planning reduces risk but side effects can still occur. ^[2] Systemic therapies and chemoradiation regimens used for head and neck cancers may produce eye symptoms such as blurred vision, redness, pain, or light sensitivity. ^{[7] [8]}
• Specific tumor sites: Nasal cavity and sinus cancers can present with swelling around the eyes and double vision as disease advances. ^[9] Nasopharyngeal tumors may enter the skull base and cause vision problems, headaches, and facial pain. ^[4] As nasopharyngeal tumors spread to the skull base, they may compress nerves that affect vision. ^[3]

Visual symptoms to watch for

• Changes in vision quality: Blurred, cloudy, or distorted vision; trouble seeing in the dark; halos around lights; or changes in color vision. ^{[10] [7]}
• Double vision (diplopia) or misalignment: New-onset double vision can occur with orbital invasion or cranial nerve involvement (nerves controlling eye movement). ^[9] Diplopia is also reported in skull base tumors due to sixth nerve palsy. ^[11]
• Eye discomfort or surface symptoms: Dry, watery, gritty, red, or painful eyes; sensitivity to light (photophobia). ^{[10] [7]}
• Neurologic eye signs: Progressive ophthalmoplegia (difficulty moving the eye), facial numbness in the forehead or around the eye, and painful eye movements especially with severe orbital or forehead pain may signal perineural tumor spread and orbital apex involvement. ^[6] Multiple cranial nerve palsies with eye movement problems have been described with perineural spread from cutaneous facial cancers. ^[5]
• Swelling or pressure signs: Pain and swelling around the eyes can occur with tumors in the sinuses and nasal cavity. ^[12] Swelling around the eyes and decreased sense of smell may be early clues in sinus cancers. ^[9]

Red flags that need urgent medical attention

• Rapidly worsening or sudden vision loss or new severe double vision, which can indicate optic nerve or skull base involvement. ^[13] Unexplained progressive loss of vision warrants urgent imaging of the skull base. ^[13]
• Severe, persistent orbital or forehead pain with numbness that evolves into eye movement problems (ophthalmoplegia) or vision loss, suggesting perineural spread to the orbital apex. ^[6]
• New multiple cranial nerve symptoms (eye movement issues plus facial weakness or numbness), which may reflect central spread along nerves. ^[5]

How doctors evaluate vision changes in head and neck cancer

• Detailed eye exam and neuro‑ophthalmic testing: Color vision, pupillary responses (to detect optic nerve conduction issues), and formal visual field testing are used to pick up subtle optic pathway involvement early. ^[13]
• Imaging of skull base and orbits: MRI or CT helps assess orbital invasion, optic nerve compression, and cranial nerve involvement at the skull base. ^[13] When sinonasal tumors invade the orbit, imaging guides surgical planning and radiation fields. ^[14]
• Multidisciplinary care: Teams may include ENT/head & neck surgeons, neurosurgeons, radiation oncologists, medical oncologists, and neuro‑ophthalmologists to balance tumor control with preservation of vision. ^[15] Coordinated rehabilitation services can address vision-related side effects after treatment. ^{[1] [2]}

Can vision be preserved?

Vision preservation is often possible with careful selection of treatment and reconstruction when the orbit is involved but the optic nerve and critical structures can be spared. ^[16] In appropriately selected sinonasal cancers with orbital involvement, surgery plus adjuvant radiation can achieve local control while maintaining adequate eye function. ^[16] Even when orbital contents are preserved in maxillary sinus cancer, survival may remain favorable, though ocular function preservation rates vary by treatment approach and extent of invasion. ^[17]

Practical steps if you notice eye symptoms

• Report any new visual changes promptly, including blurriness, double vision, color change, light sensitivity, eye pain/redness, or gritty/watery eyes. ^{[7] [10]}
• Protect your eyes with sunglasses and lubricating drops if advised, especially during or after treatments affecting the orbital region. ^{[10] [7]}
• Seek urgent evaluation for rapidly worsening vision, severe orbital pain with numbness, or new multiple cranial nerve symptoms, as these may indicate skull base or optic pathway involvement that requires timely imaging and specialist care. ^{[13] [6] [5]}

Summary

Head and neck cancers particularly those in the sinonasal region or nasopharynx and their treatments can cause vision problems by affecting the eye muscles, optic nerve, or nearby cranial nerves at the skull base. ^{[1] [3]} Watch for blurred or double vision, eye pain or redness, light sensitivity, gritty/dry eyes, color vision changes, swelling around the eyes, and neurologic signs like painful eye movements or facial numbness, and report these promptly. ^{[10] [7] [9]} Early assessment with neuro‑ophthalmic testing and imaging can help protect vision while guiding safe, effective treatment. ^{[13] [14]}