Bell’s Palsy: A Half-Smile Paralysis

Author: Jenny Liu |

Droopy eyelid? Can’t frown? Can’t smile? But only on one side of your face? Ding dong! Bell’s palsy!

Bell’s palsy is defined as the sudden weakness or paralysis of one side of the face due to the malfunction of the facial nerve, also known as the 7th cranial nerve.1,2 This cranial nerve is not only responsible for all the facial expressions, but it is also responsible for the salivary and tear glands. In addition, the nerve also allows us to detect tastes in the first ⅔ of our tongues and controls one muscle in the ear for hearing.2 Bell’s palsy affects only one side of the face, and its symptoms include a droopy eyelid, excess tearing, inability to move the upper lip, droopy mouth, excess drooling, loss of taste of the anterior ⅔ of the tongue and increased sensitivity of the ear on the affected side. Although the exact cause of Bell’s palsy remains unknown, recent evidence has shown that viral infections could cause the swelling of the facial nerve, and therefore can cause symptoms of the facial paralysis.2 Normally, Bell’s palsy resolves on its own without any treatment within 6 months while severe cases are treated with corticosteroids.2

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Symptoms of Bell’s Palsy 1

Patients with Bell’s Palsy have high risks of the corneal damage as they usually have trouble closing the eyelid of the affected side. As optometrists, our goal is not to treat all the symptoms but rather relieve them in any way we can. We would advise patients to instill non-preserved artificial tears frequently while awake and ophthalmic lubricating ointments at bedtime.3 This would help with the dry eye symptoms they get from not being able to blink and the poor tear quality and/or volume due to the facial nerve damage. Wearing an eyepatch or using medical tape to forcefully close the affected eye when sleeping can prevent it from getting scratched in cases which the eyelid function is markedly reduced.3 It is important to visit your optometrists immediately when you are experiencing symptoms of Bell’s palsy and regularly until you are fully healed. Optometrists can monitor the integrity of the corneal epithelium, which is the outermost layer of the eyeball, to decrease the chance of exposure keratopathy. Exposure keratopathy is the damage to the outermost layer of the eye due to prolonged exposure to the outside environment, and it can eventually lead to vision loss.

If you have any concerns or questions about your eyes or Bell’s palsy, you can schedule your regular eye exam at Chan Optometry, and we will be glad to help you.

As a leading eye doctor and optometrist in Markham, Ontario, at Chan Optometry, we conduct eye exams and offer optometry services that include laser eye surgery consultation and co-management, contact lenses, orthokeratology and other speciality contact lenses, cataract surgery co-management across Markham, Richmond Hill, Vaughan, Stouffville, Aurora, Newmarket, North York and Scarborough.

Call (905) 604-6856 for more inquiries, or get in touch with us by clicking here.

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Jenny is the 2019 summer intern at Chan Optometry. She is an optometry student at Illinois College of Optometry in Chicago. Upon graduating in 2022, she wishes to pursue residency in either vision therapy or pediatrics. She hopes to start her career in the Greater Toronto Area after that. Jenny grew up in Vancouver, B.C and moved to Ontario to complete her Bachelor of Science degree at the University of Waterloo. Jenny is fluent in Cantonese, Mandarin, and English.


  1. Osmosis. “Bell’s Palsy - causes, symptoms, diagnosis, treatment, pathology.” Online video clip. Youtube. Youtube. 26 Mar 2018. Web. 05 Jun 2019.
  2. Rubin, Michael. “Bell’s Palsy.” Merck Manual, 2017,,-spinal-cord,-and-nerve-disorders/cranial-nerve-disorders/bell-palsy
  3. Skorin, Leonid. “How to Tell Bell’s from Masqueraders.” Review of Optometry. 19 May 2003,

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