Surgical Conditions of the Eye Flashcards
What are some clinical signs of ocular pain?
Squinting Third eyelid protrusion Redness Increased blink rate, blepharospasm Increased lacrimation and overflow Photophobia Rubbing Miosis (contraction of pupil)
What is the purpose of topical lubricants?
Provide a protective layer
Moisturise dry eyes
Soothe
Lubricate
What is the purpose of topical mydriatics?
Pupil dilation
Muscle spasm release
Comfort
What is the purpose of topical antibiotics?
Treatment/prevention of bacterial infection
What is the purpose of topical NSAIDs?
Treat inflammation within anterior eye
What is the purpose of topical carbonic anhydrase inhibitors?
Reduce IOP (glaucoma) Decrease the production of aqueous humour
What is the purpose of topical prostaglandin analogues?
Reduce IOP (glaucoma) Increase the aqueous outflow
What abbreviations are used to describe which eye is affected?
OS = Ocular Sinister (left eye) OD = Ocular Dexter (right eye) OU = Ocular Uterque (both eyes)
What pre-anaesthetic considerations should we have prior to ocular surgery?
Full physical examination
Pre-anaesthetic blood tests?
Eye drops prior to surgery?
IV catheter - increasing venous pressure will increase ocular pressure
Diabetic patients - insulin or no insulin?
When do we clip for ocular surgery?
Do clip for eyelid surgery
Do not for corneal/intraocular surgery
How do we make up povidone iodine solution for the globe and the eyelids?
Globe = 1:50 with sterile saline Eyelids = 1:10 with sterile saline
How do we prep for eyelid surgery?
Wear gloves
Apply copious amounts of lubricating gel to eye(s)
Use small, clean, sharp clippers
Clip area required as close to skin without causing irritation
Use gauze swabs and sterile saline to remove gel and hair from eye(s)
Prep globe first with 1:50 povidone iodine solution
Then prep eyelids with 1:10 povidone iodine solution
After 3 mins, flush globe with sterile saline to prevent corneal toxicity
How do we prep for corneal/intraocular surgery?
Wear gloves
Prep globe with 1:50 povidone iodine solution
After 3 minutes, flush globe with sterile saline to prevent corneal toxicity
How do we clean microsurgical instruments?
Immediately after procedure, remove any gross material with distilled water and soft nail brush/toothbrush
Check instruments for damage
Place in ultrasonic cleaner for 5-10 minutes using a neutral pH ultrasonic cleaning solution (ensure they are on a finger mat, not touching each other)
Allow instruments to air dry
Place in microsurgical tray in silicone finger matting (they should not touch one another)
TST strip, double-wrapped, sterilise by autoclave 134-137 degrees C
Allow kits to dry thoroughly before storing
Store flat
How do we care for ocular patients post-op?
Remember - increased venous pressure = increased IOP Harness walk, not collar and lead No jugular samples Buster/soft collar Recognise and monitor pain Admin pain relief/eye medication Keep wound clean and patient calm
What ocular conditions are commonly seen in practice?
Exophthalmos (abnormal protrusion of eyeball) Globe proptosis Entropion (eyelids inverted) Keratoconjunctivitis sicca (KCS) Conjunctivitis - inflammation (hyperaemia) Corneal ulcers Uveitis Opacity of the lens (cataracts) Retinal detachment
What equipment do we need for an ophthalmic exam?
Dark room Pen torch Direct ophthalmoscope 20D condensing lens Tonometer Consumables e.g. Fluorescein, Schirmer Tear Test strips etc.
How do we restrain patients for ophthalmic examination?
Minimal is best
Calm and confident
Patient seated at edge of table (unless large)
Place one hand over back towards chest and one hand supporting under the chin
How should we handle fractious patients when restraining for an ophthalmic exam?
Muzzle
Towel
+/- chemical restraint
How should we handle blind/visually impaired patients?
Talk to them before you approach them
Go slow
Guide them carefully when walking
How can we avoid increasing venous pressure to avoid increasing IOP?
No neck leads - harness walk Gentle handling Keep barking/stress to a minimum No jugular samples No temperature checks May need to sedate prior to placing IV catheter (saphenous preferred) Ensure smooth recovery from anaesthesia
What are the stages of the ophthalmic exam?
History Distant examination and close examination Schirmer tear test (+ sample collection) Neuro-ophthalmic examination Close direct ophthalmoloscopy Indirect ophthalmoscopy
What history do we need to collect about ocular patients?
Signalment General history Known illness/signs of other illness Previous ocular conditions +/- treatment Current ocular complaint +/- any treatment Vision?
How do we carry out a distant and close examination?
Animal attitude - body condition
Face - symmetry, ocular discharge
Eyelids - palpebral fissure, size, colour, swelling
Eyeballs - position, size, direction, movements, retropulsion
Observation of pupil - static (symmetry, size, shape) and dynamic (PLR)
Use of direct ophthalmoscope - retro-illumination
What reflexes do we test in the neuro-ophthalmic exam?
Pupillary light reflex (PLR) Dazzle reflex Menace response Tracking response Visual placing Maze test (in bright and dim light)
What are some common diagnostic tests?
Schirmer tear test Bacterial swab, cytology, culture and sensitivity Fluorescein staining IOP measurement Gonioscopy Ocular ultrasound Electroretinogram (ERG) CT and MRI
Describe an intraocular pressure (IOP) measurement.
Schiotz tonometer, Tonopen, Tonovet
Use topical anaesthetic with Schiotz tonometer and Tonopen
What is a normal intraocular pressure?
Normal IOP = 10-25mmHg
What is the normal value for a Schirmer tear test?
Normal dog = 15-25mm over 1 minute
Describe gonioscopy.
Indications = patients with risk of developing inherited glaucoma/patients with confirmed glaucoma (increased IOP)
Use a special lens to view the drainage angle
Local anaesthetic applied prior to performing
Why do we use CT and MRI?
Investigating exophthalmos
Main differentials = retrobulbar abscess, retrobulbar neoplasia, foreign body
