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