Eye exam Flashcards
Visual exam of adnexa
Accessory structures of the eye
* Eyelids, eyelashes, skin around eye
* Secretions
* Conjunctiva, sclera, 3rd eyelid
* Wounds, asymmetry, swelling, squinting, hair loss
* Masses, foreign material
* Redness, icterus
* Always indicate left (OS), right (OD), both (OU)
Visual exam of the globe
- Overall size
- Bulging, recessed or sunken position
- Cornea
- Cloudiness, haziness, redness, presence of blood vessels
- Anterior chamber
- Pupil size
- Dilated, constricted, asymmetrical
- Always indicate left (OS), right (OD), both (OU)
History for eye exam
- General health
- Vision reduction, vision loss
- Redness, rubbing, discharge, pain, bigger, smaller
- When did it start? How long?
- Staying the same, getting worse, getting better, comes
and goes - Risk factors and triggers
Eye exam
- Is part of every physical exam
- A full physical is part of every eye exam
What to look for in eye exam secretions
- Secretions
- Don’t clean until vet has seen it
Serous(tearing/epiphoria)
Mucoid Mucopurulent/Purulent
Ophthalmoscope exam
- Used to assess inside of anterior chamber, changes to the lens and fundus
- Fundic exams may require dilating pupils
- Usually performed by the veterinarian
Basic eye tests and procedures
- Schirmer tear test (STT)
- Local anesthetic (proparacaine/Alcaine)
- Conjunctival swab
- Eye flush
- Intraocular pressure (IOP) measurement
- Dilation of pupils (tropicamide (Mydriacyl), atropine)
- Fluorescein stain
Schirmers tear test
- Measures tear production
- Detects lack of and excessive tear production
- First part of an eye exam or manipulation
- Before eyes are cleaned/flushed/medicated
- STT strips are sterile filter papers with dye that moves across the paper due to capillary draw from tears
- Sterile strips usually come in packages of 2
- Often labelled “L” and “R”
- Fold at the notch while still in the sterile package
- Remove one strip at a time, and place the folded end under the
lower eyelid, around the middle of the eyelid - Eyelids can be open or closed
- Count to 1 minute from time of placing strip
- Record distance dye has moved in 1 minute
- Repeat in other eye - ALWAYS measure both eyes
Normal ranges of STT strips
Dogs: 12-15 mm /min
Cats: 10 mm/min
Horses: 20 mm/min
Topical anesthetic is and indicated for
- Proparacaine 0.5% is most commonly
used (Alcaine) - Blocks local nerve conduction to control pain
- Indicated for:
*Painful eye - pain causes squinting
*Cytology/scraping/debridement
*Adjunct for eye surgery, Schiotz
Conjunctival swab is and used when
- Sterile swab is taken from lower conjunctiva
- Usually to diagnose infection with the following tests
- PCR (feline upper respiratory disease complex)
- Culture (bacteria)
- Note that aseptic technique is a must:
- Sterile swab
- Aseptic technique (gloves, sterile surface)
- Sterile container (serum collection tubes work)
- Transport media if culture
- Freeze/fridge if for PCR
Conjunctival swab technique
- Put on sterile gloves (exam gloves are fine)
- Sterile opening of swab
- Moisten end of swab with sterile saline
- Pull down gently on lower eyelid
- Swab conjunctival sac (avoiding hair on face and eyelid margins)
- Place swab in transport media in fridge if culturing. Place swab in sterile serum collection tube (break off portion of handle that is
sticking out of tube) and place in freezer for PCR - Submit in a timely manner for culture/PCR
Conjunctival scraping is and why do it
- This test collects cells from the conjunctiva of the eye for analysis
- Indicated when there is chronic conjunctivitis or ocular discharge, conjunctival masses, or when distemper or chlamydial infections are suspected
- Requires a topical ophthalmic anesthetic such as Alcaine®, a number 10 sterile scalpel blade and several microscope slides
Conjunctival scraping technique
- Instill 2 drops of anesthetic into the eye, wait 30 seconds and apply 2 more drops
- Push the globe of the eye to make the nictitating membrane rise up
- Evert the lower eyelid and using the blunt end of the scalpel blade press firmly against the tissue and scrape along the surface
- Gently blot the tissue onto a glass slide, air dry, and stain for cytology
- The tissue sample may also be placed into sterile saline for PCR (Polymerase chain reaction) testing
Tonometry is and identifies what
- Measuring the intraocular pressure (IOP)
- IOP is the pressure exerted against the outer walls of the eyeball from the contents inside
- Identifies inflammation and glaucoma
- Uveitis - Inflammation in the anterior chamber, causes drop in IOP
- Glaucoma - Increased pressure in the eye
Normal pressure range of eyes
Normal pressure range is 15-25 mmHg across all species
Dogs 15 -18 mmHg
Cats 17-19 mmHg
Horses 17-28 mmHg
3 ways to measure IOP
- Schiotz tonometer
- Tonopen
- Tonovet
Schiotz tonometer does what and is contraindicated when
- Measures the amount of indentation of the cornea by applying a calibrated weight and measuring the deflection the weight produces in the tonometer’s scale
- The greater the indent, the lower the IOP
- Contraindicated if eye ulcer as could traumatize cornea further and risk rupture
Schiotz tonometry directions
- Calibrate the Schiotz tonometer as per lab
- Get patient to relax. Hold animal so nose is up in the air. Cornea needs to be parallel to the ground
- Avoid pressure on neck as that will artificially increase IOP
- Apply topical anesthetic to both eyes
- Gently rest Schiotz on the cornea and take 3 readings from each eye. Use the provided table to convert reading to mmHg
- Record the results in mmHg for each eye
- Discard any reading that is not like the other two. Take the average.
Restraint and anesthetic for eye exams
- Topical anesthetic is:
- Highly recommended for the Schiotz
- Optional for a Tonopen
- Not required for a Tonovet
- Two people required to perform Schiotz and Tonopen because of restraint
- Animal must be relaxed and cannot apply pressure to the neck or will elevate IOP
Tonopen is
Easily skewed results by improper instrument use, improper placement on the cornea, improper restraint
* Use sterile cover for each patient
* Head/pen can be at any angle, but must be perpendicular to cornea. Hold pen within 1/2 inch from cornea
* 3 repetitive taps are required for average measurement
* Works by determining force required to flatten given area of the cornea
Tonovet is
- Rebound tonometer
- Small probe is suspended in the unit with a magnet. During reading, probe is pushed out of unit which rebounds off cornea. IOP is calculated by current created when probe rebounds
- Probe must be parallel to floor for probe to move in and out of unit properly
- Probe must be perpendicular to cornea and 1/6 inch away from cornea
- Requires 6 readings to provide an average
- Does not require topical anesthetic. Very accurate
Pupil dilation
- Most common are tropicamide (lasts 20 minutes) and atropine (lasts 12 hours)
- Used to dilate pupils to allow better view of lens and fundus
- Apply after vet has examined the anterior chamber and reflexes
Fluorescein stain is and used for
- This stain is orange when concentrated and green when
dilute under blue light - Used to detect physical breaks (scratches) in the corneal epithelium
- Intact corneal epithelium has high lipid content that prevents dye from adhering
- Underlying stroma has high water that adheres to the dye
- Can also use to test patency of the nasolacrimal ducts
When to do a fluorescein stain and what materials are needed
- Vet will let you know if they need this test done
- ALWAYS AT THE END OF THE EXAM
- Materials/equipment:
- Fluorescein test strip
- Eye wash or sterile saline (room temperature)
- Eye wash has a slightly different tonicity than 0.9% NaCl
- Tissue or gauze
- Blue light (ophthalmoscope)
- Room that can be darkened
Steps on how to preform fluorescein stain
- Open strip but leave on sterile surface
- Moisten the end of the test strip with a few drops of sterile eyewash
- Raise upper eyelid and touch tip of strip to the bulbar conjunctiva for 1 second (Can also touch to the sclera)
- Allow patient to blink to move dye around surface of eye
- Darken room and view surface of cornea with blue light.
- Record any fluorescence
* Present or not, size of stained area, shape, location, if stained
throughout or areas that are not stained
* Drawing a diagram (or taking a photo) is best practice - Can observe for stain exiting ipsilateral nares
* This indicates the nasolacrimal duct is patent - Rinse the eye(s) well with sterile eye wash to remove unbound stain.
Cleaning around the eyes
- Eyes need to be clean before applying medications
- Clean the area around the eye first with a gauze moistened with warm water
- NEVER use alcohol or iodine around the eyes – can cause corneal trauma
- If there is excessive discharge the eye may require irrigation (flushing) with an eye wash solution
- If shaving around the eye, first cover eye with eye lubricant
- Shave
- Rinse eye with eye wash – this will remove both the lubricant and hairs caught in it
Rules for eye meds
Always triple check to make sure it is the right medication
1. When you pick up the medication – check that it matches the file
2. Before applying the medication – check that it matches the file
3. When returning the medication – check that it matches the file
Always check the dose
1. Which eye (OS – left, OD – right, OU both)
2. Order of medications
3. Quantity/number of drops
4. Frequency
ALWAYS give drops first
* Ointments create a protective coating over the eye and will not allow medicated drops to be absorbed
Wait at least 5 minutes between medications
* 15 minutes is better
* This allows for absorption of the medications
Eye drops
- Often requires two people; one to restrain and one to administer the medication
- Tilt the head back
- Hold the eyelids open with the thumb and index finger of one hand
- Rest the hand holding the medication on the patient’s head and apply one drop of medication on the sclera of the eye
- Do not touch dispenser tip to cornea
- Causes contamination of bottle
- May cause trauma to cornea
Eye ointments
- After any drops have been given
- Provides a protective coat to the eye surface
- Often requires two people
- Tilt the head back
- Hold the eyelids open with the thumb and index finger of one hand
- Apply a 3-5 mm ribbon of ointment to the (upper) sclera of the eye
- Either have the patient blink or close the eyelids once or twice to spread the ointment over the eye
- Never touch dispenser tip to cornea
Precautions to take while administering eye medication
- NEVER touch the eye with the tip of the dropper/ointment bottle(s)
- Can damage the eye
- Contaminates the eye medications which could cause an infection
- If ophthalmic eye drops/solutions appear cloudy, contain particles, or have a colour change, they should be discarded
- Elizabethan collars are often put on the patient to prevent the animal from rubbing or scratching at the eye(s)
- They are worn for 24 hours a day, 7 days a week until issue resolved or stated otherwise by veterinarian
- 7-14 days, depending on the procedure
Owner info on eye medications
- Treatment and medications are prescribed by the vet
- Role of RVT to review prescribed medications with owners AND demonstrate how to administer
- Give first dose in clinic when possible as demo
- Have owner give in second eye
- Role of RVT to tell owner about:
- Order of medications, time in between each
- Cleaning around the eye(s)
- Reasons for the medications – increases compliance
- Follow up instructions (what to look for, compliance, how to tell if improving or getting worse, etc.) <– Ask the vet for what to tell owner if unsure
- Write down a dosing schedule if 3 or more medications
Flushing the nasolacrimal duct is and tools needed
- This procedure is performed to remove minor obstructions from the nasolacrimal duct
- It is indicated when the fluorescein dye test indicates that there is not a patent nasolacrimal duct
- It requires
*Gauze sponges
*Topical ophthalmic anesthetic
*Sterile 23-27 gauge nasolacrimal cannula
*3 ml syringe filled with sterile saline or eye wash
Steps in preforming a flushing of the nasolacrimal ducts
- The patient may require sedation
- Clean the eye first
- Instill 2 drops of topical ophthalmic anesthetic, wait 30 seconds and apply 2 more drops
- Restrain the head and roll out the upper eyelid exposing the superior punctum
- Use the lacrimal cannula and slide it along the inner lid margin toward the medial canthus
- Once the cannula is well seated flush 2-3 ml of sterile saline or eye wash
through the punctum - Observe fluid emerging from the inferior punctum
- You should be able to see fluid coming from the nostril when you occlude the inferior punctum
- If saline/eye wash does not come through the inferior punctum, cannulate the lower punctum and flush it as well
Ophthalmoscope cleaning
*Does not touch patient, so cleaning is only whenvdirty
* Clean head with gauze lightly wet with alcohol – Never immerse
* Wipe viewing window with a cotton swab or lens paper dipped in alcohol or lens cleaner
* Be careful not to damage/move the mirror (should not require moving)
*Never leave the ophthalmoscope upright on a counter/table/shelf
* Dropping will damage the mirror
Otoscope/Ophthalmoscope maintenance
*ALWAYS turn off when not in use
*Never submerge
*Come with replaceable batteries or rechargeable batteries
*Rechargeable batteries should be charged regularly
* Most are charged by removing the head and plugging the handle into a regular socket
* Change batteries when light starts to dim even after charging and with a new bulb
Replacing bulbs
*Make sure power is off before changing
*It is recommended to wear protective eyewear as halogen bulbs are pressurized
*Remove bulb and replace with the proper manufacturer’s bulb
* Typically, bulb location is at the base of the head where it attaches to the handle
