The Wet Eye Flashcards
What does the prefix Blephar mean?
pertaining to the eyelid
What does the prefix Dacryo mean?
pertaining to the NLS
What does the prefix Kerat mean?
pertaining to the cornea
What does the prefix Irido mean?
pertaining to the iris
What does the prefix Cyclo mean?
pertaining to the ciliary body
What does the prefix Phac mean?
pertaining to the lens
What does the prefix Hyalo mean?
pertaining to the vitreous
What is the term used to describe a wet face due to tearing?
Epiphora
What are the two umbrella causes of epiphora?
Lack of drainage through the NLS or irritation leading to reflex tearing. Hence investigation should focus on both blockage and irritants
What are the two glands that produce tears and what proportion of tear production do they account for?
The lacrimal gland under the dorsolateral orbit (70%) and the gland of the third eyelid (30%)
Why does epiphora usually occur medially?
Because tears are brought to the medial canthus by blinking and so accumulate here if they are not drained by the tear ducts. May be seen laterally in some cases however
What are two examples of epiphora not from the medial canthus?
Lateral entropion, central lower eyelid ectropion
What are the parts of the nasolacrimal system in order?
Puncta, canaliculus, lacrimal sac, nasolacrimal duct (intraosseous), potential additional duct openings (may be as far back as the nasopharynx), nasal punctum in the lateral nasal wall
What two things are different about the NLS in rabbits?
They have a single large punctum in the medial conjunctiva of the lower lid, the NLD is interosseous and tortuous, it runs close to the primary maxillary incisor and bends over the route. (Important site for NLD blockage in association with tooth problems)
Which species is well known for having a large nasal punctum and what is the potential use of this in treatment?
Horses, means you can cannulate retrogradely
What is the Jones test?
Apply fluorescein to the eye, allow the patient to blink normally, wait for up to 4 minutes, should appear in the ipsilateral nostril in the first couple of minutes. If delayed it may be going into nasopharynx through accessory opening or there may be a partial blockage. If it doesn’t come through at all suspect blockage and flush
Which way should the head be pointing when you flush the NLS and why is this important?
The head should be pointing downwards so that if any fluid comes out in nasopharynx/throat area it doesn’t get aspirated
What could you potentially use if you didn’t have access to a nasolacrimal cannula?
IV catheter without stylette however it may be too floppy
What can you do to counteract pain during flushing?
ALWAYS use topical anaesthetic (proxymetacaine 0.5%). Sedation for some dogs, all cats and probably all horses. Obstructions may be painful and may require GA, don’t force it, imaging if it won’t go through
What congenital abnormality can cause epiphora by blockage?
Imperforate punctum/puncta, can be unilateral or bilateral, upper and/or lower puncta, may also affect cannaliculi (malformation or aplasia)
What non congenital causes of blockage are there?
post traumatic/inflammation. History or previous disease or trauma may give clue. Herpes virus in cats
How do you treat a blocked punctum?
Cannulate the other puntum (on the same side) and pulsate fluid, you will see where it tries to get through on the opposite eyelid, make a small incision over the pulsation with the tip of an 11 blade and pass a suture through the NLS. Leave it here for 2 weeks to allow epithelialisation around it to maintain patency. Make sure to check the other side as may be bilateral
What should you do if it is not possible to canulate through the other punctum?
Retrograde cannulation if possible. Difficult and will require GA. May need to consider CT/dacryocystorhinography study with contrast
How would you diagnose blockage of the NLD?
Bulging under the skin near the medial canthus, mucous production/manually expressed by gentle massage, area may be surgically explored (GA), foreign material, imaging
How do you treat blockage of the NLD?
Cannulate with suture and tie as before, leave 14 days
Epiphora may also be caused by stimulation of the pain receptors. What are the 3 sources?
Ocular surface (eyelids/TE, conjunctiva, cornea) Intraocular structures Retrobulbar area
What might cause corneal pain?
problems with nearby hairs, the eyelid or the third eyelid
exposed corneal nerves-corneal ulcer
foreign object
The cornea is very sensitive
Primary causes of eyelid/TE problems
Traumatic, inflammatory/immune mediated/infectious e.g. bacterial (e.g. Staph), mycotic (ringworm), parasitic (demodex), Leishmania (abroad), immune mediated (e.g. pemphigus)
What is hordeolum?
A stye-infection of the meibomian glands or glands of zeiss/moll. very painful
What is chalazion?
Non-painful itself but irritates cornea. Material blocked inside meibomian gland, gland bursts leading to macrophage reaction and granuloma
Aetiology and treatment of staphylococcal blepharitis
young to young adult dogs, hypersensitivity + self trauma, leads to skin abscesses and ulcers. Treatment: clean, debride, lance if necessary, buster collar to prevent self trauma (4-6 weeks), AB e.g. cephalosporin orally and fucithalmic, +/- oral/injectable steroid short term
What is the pathophysiology and treatment of foreign body under the third eyelid?
Corneal pain due to contact with cornea and possible ulcer formation. Topical anaesthetic (proxymetacaine) and tools are needed (wire eyelid speculum, von graffe forceps). Topical AB to support (Chloramphenicol, Fucithalmic). Should heal quickly once FB removed
What would you use to suture the third eyelid?
6-0 vicryl. round bodied needle, need magnification and smaller equipment as is delicate procedure
What are the two treatments for protrusion of the third eyelid
Morgan’s pocket technique-Conjunctiva on the posterior surface of the third eyelid is sutured over the prolapsed gland
Anchoring techniques
What causes follicular conjunctivitis?
Young animals. Allergic response to environmental allergens, mostly third eyelid, more obvious on bulbar side than visible side
How do you treat follicular conjunctivitis?
Avoidance and protection (preservative free lubricant), topical anti-inflammatory, sodium chromoglycate-a mast cell stabiliser. Tricky, needs to be used just before degranulation
What can cause primary infectious conjunctivitis in small animals?
Chlamydophila (young cats, bi or uni, v hyperemic conjunctivitis, doxycycline)
FHV-1 (more of a corneal problem-ulcerative, affects conjunctiva secondarily)
What are the three common causes of conjunctivitis in farm animals?
IBR-signs in adults are URT ‘red nose’, and ocular redness and discharge, ocular development problems in utero
Moraxella bovis-aka pink eye, fomites, typically seasonal, very hyperemic conjunctivitis, new forest eye
Listeria monocytogenes-aka silage eye, fomites typically seasonal
What is corneal LPI?
Lymphocytic plastacytic infiltration aka Pannus/chronic superficial keratitis (CSK)
May be cornea only, third eyelid and cornea or third eyelid only (aka plasmoma)
What is EK
Eosinophilic keratitis and keratoconjunctivitis (cats)
How do you treat trichiasis?
cut the hair
How do you treat distichiasis?
electrolysis if many glands, wedge resection if single/few
How do you treat ectopic cilium?
wedge resection
What kinds of eyelid tumours can you get in dogs and are they generally malignant or benign?
Meibomian gland adenoma and papilloma (commonest two), also mast cell tumours
What kinds of eyelid tumours can you get in cats and are they generally malignant or benign?
variable but most are malignant
SCC, melanoma, MCTs
What kinds of eyelid tumours can you get in horses/cattle and are they generally malignant or benign?
most are malignant
sarcoid, SCC, melanoma
What is the rule of thumb for how much eyelid you can remove in a wedge resection and be able to close without tension?
25%, however some breed difference e.g. you can take more off something like a spaniel with looser eyelids than something like a Chihuahua which has very little to play with!
What modification to the wedge resection might help relieve tension?
A house resection
What two sutures are normally used to close a wedge resection?
Internal tarsal plate suture followed by a figure 8 suture. May sometimes just do a figure 8 e.g. in a very young animal
Info slide:
upper eyelid agenesis in cats-lateral upper eyelid is missing (eyelid coloboma), lead to trichiasis. requires reconstruction
X
What is the name of the procedure used to correct an entropion?
Celsus-Holtz-a slit of skin is removed to tighten the area so there’s not enough excess to role inwards. Always assess how much to take out after administering topical anaesthetic to remove the spasmodic element. Suture with 6-0 absorbable material and close according to the rule of bisection
Long eyelids lead to in turning so possibly wedge resection
Treatment of ectropion
Possibly wedge resection
What ethical considerations are there with treating entropion/ectropion?
Showing-Owner should declare if entering any showing classes that their dog has had surgery to the eye which will have altered the way that it looks (for better or worse) and that this was for its health rather than cosmesis.
Repair should only be done for health reasons
Breeding may not be ethical
Owner should inform the breed club if it’s a show animal
Intra ocular irritants can be very painful, cause spasm of the ciliary and iridal muscle, leads to miosis and photophobia. Causes are various e.g. glaucoma, uveitis. Prolonged or intense corneal stimulation can cause a reflex uveitis
iris goes into spasm with painful corneal ulcers
What are 3 examples of retrobulbar disease which can cause irritation?
Abscessation/cellulitis (painful)
Salivary Gladn disease
Neoplasia (rarely painful)
