Episode 37 - Bow Ties and Blink Reflexes

Bow Ties and Blink Reflexes: Periocular Perils on SkinFlint In this month's episode, Sue & John invite a well known vet with his eye on pet eyes - David Williams. (00:00) John opens SkinFlint. Today’s focus is the periocular region — small real estate, big consequences — from itchy eyelids and rogue hairs to lumps and lesions that can threaten vision. Chapter 1: The Eyelid Is the Windshield Wiper (03:54) David Williams joins: associate lecturer in veterinary ophthalmology at Cambridge, teaching students and travelling between practices to manage eye cases. He’s been operating that morning on a severe corneal ulcer — a reminder that “eyelid problems” often matter because of what they do to the cornea. (06:10) Mucocutaneous junction basics. David frames the eyelids as protective, moving structures that maintain the ocular surface. The lid margin is more than skin: it includes meibomian gland openings that support tear film stability. (07:21) Tear film (briefly, promise). David describes modern tear film understanding as a mixed mucin and aqueous layer with a lipid surface. The eyelid spreads it over the cornea; tears behave as a non Newtonian fluid, becoming “runnier” as the lid moves, which helps smooth distribution during blinking. (09:08) Rubbing: skin itch vs eye pain. Sue highlights the GP dilemma: is the dog rubbing because periocular skin is pruritic (allergy) or because the eye is painful? David describes the vicious cycle (irritation → rubbing → more inflammation) and stresses looking at both eyelids and the globe. Stopping self trauma (sometimes a collar) can be part of breaking the loop. (11:01) Red eye triage and eyelid eversion. David’s practical tip: clinicians don’t evert eyelids enough. If both palpebral conjunctiva (inside the lid) and bulbar conjunctiva (on the globe) are inflamed, conjunctivitis is more likely. If the globe looks red but the inner lid does not, widen your differential (including uveitis and glaucoma). Don’t guess from the outside. (11:45) The lash trio explained. Trichiasis: normal hairs rub the cornea due to lid conformation. Distichiasis: extra lashes from the meibomian gland orifices at the lid margin. Ectopic cilia: a lash emerges through conjunctiva and points at the cornea — often very irritating. David suggests checking for allergy clues elsewhere (paws, general pattern) if you suspect pruritus is the driver. (13:33) Distichiasis: common, not always guilty. Many dogs have distichiae in both eyes without ulcers. Lashes may delay healing rather than cause the initial lesion. Plucking, freezing or electrolysis can lead to regrowth (sometimes shorter and more abrasive). If treatment is truly needed, David prefers approaches that remove the lash follicle within the eyelid to reduce recurrence. (16:45) Older Cockers and “saggy lash syndrome”. David describes age related lid changes in Cocker Spaniels where long lashes start rubbing persistently. He flags the importance of a Schirmer tear test, as dry eye commonly co exists and must be addressed alongside lid conformation. (18:15) Two quick diagnostics. A topical local anaesthetic drop can be used diagnostically (briefly) to see if discomfort reduces, but repeated use is unsafe for the corneal epithelium. David also reminds listeners to check the third eyelid: lymphoid follicles on its inner surface can keep an eye irritated and are only found by everting it. Chapter 2: Lumps, Bumps and the Cat Exception Clause (22:56) Eyelid masses: chalazion or tumour? David frames the common dilemma as meibomian gland inflammation versus neoplasia, though many cases end up managed surgically either way. In dogs, most eyelid tumours are benign (often meibomian adenomas/epitheliomas) and are usually suitable for wedge resection. His bias: remove earlier rather than later (smaller surgery, lower anaesthetic risk than waiting). (24:38) When heat helps. If you suspect a meibomian gland abscess or granulomatous lesion, David suggests warm compresses applied regularly (as hot as comfortably tolerated) to encourage drainage and reduce the lump. (26:20) Cats: higher suspicion. David contrasts this with cats, where eyelid tumours are more likely malignant (including squamous cell carcinoma) and may look ulcerated or invasive. He mentions photodynamic therapy as a tissue sparing option in delicate areas like eyelids. (27:40) A feline oddity to remember. A dark, round medial canthus mass in a Persian cat may be an apocrine hidrocystoma (benign), and similar lesions can appear at other mucocutaneous sites. (29:03) Melanomas. Behaviour varies by species and site. David is generally more concerned in cats than dogs and flags mucocutaneous junction melanomas as potentially more aggressive — excise when feasible. Chapter 3: VKH — The One You Don’t Sit On (30:45) Sue brings up VKH (Vogt Koyanagi Harada) syndrome, a true derm ophthalm crossover ...