Did you know? The Botox dry eye conundrum...
Did you know?
Botox is used to treat dry eye, blepharospasm and other eye diseases.
But…it has also been shown to cause dry eye.
Periocular BTX injection has become the first-line treatment for patients with blepharospasm and hemifacial spasm [435–441]. Further ophthalmological indications include persistent epithelial defects or ulcers in which protective ptosis is induced [442,443], lid retraction in thyroid eye disease , entropion [445,446], strabismus, abducens paralysis , nystagmus, gustatory tearing [433,448], superior limbic keratoconjunctivitis , refractory filamentary keratitis  and dry eye [451–455]. Periocular BTX injections are also currently widely used in facial rejuvenation to reduce lateral periocular wrinkles (crow's feet), medial nose-bunny lines and glabellar rhytids [456,457]….
A randomized, placebo-controlled, double-blind, single-dose trial in 109 blepharospasm patients reported dry eye symptoms in 18.9% of patients after injection of highly purified botulinum neurotoxin A . In retrospective studies, symptomatic dry eye was found in 0.5–7.5% of blepharospasm patients after BTX injection [438,459]. Injection of BTX-A into the lateral canthal region for aesthetic correction of crow's feet can trigger dry eye of varying severity [460,461] as reported in 1–5% of recipients .
The possible mechanisms responsible for the development of dry eye after BTX treatment are weakness of the orbicularis oculi muscle, causing reduced tone, blink strength and delayed tear clearance, and direct diffusion of toxin into the lacrimal and meibomian glands, decreasing secretory function ….