Final: Ophthalmology - Exam, Orbit, Eyelids, Conjunctiva and Lacrimal System Flashcards
What term describes vision in a well-lit environment? What about a dark environment?
Photoptic
Scotoptic
What is the term for using light that is shone into the eye to reflect against internal structures and highlight normal and abnormal features during an ophtho exam?
Retroillumination
What test can you perform to detect disease of the orbit or space occupying disease behind the globe?
Retropulsion
What test can you perform to test nasolacrimal patency? What type of solution is used?
Jones Test
Fluoroscein stain (goes in the eye, and if positive comes out the nose)
Which test is used to confirm corneal perforation?
Seidel test
(will see ‘bubbles’ when you stain the eye at the site of perforation)
What can be used to assess the health of the ocular surface because it becomes disturbed when the surface is irregular?
Specular reflection
What are the 3 tests you can perform during an exam to assess vision?
Cotton ball test
Photopic maze
Scotopic maze
What are the 3 tests used for orbital symmetry?
Orbital palpation
Dorsal view assessment
Retropulsion
Which of these pictures shows an eyeball being retroilluminated?
The bottom one
(Can see vitreal opacities)
What nerves does the palpebral reflex test? Menace response?
Palpebral: V (afferent), VII (efferent)
Menace: II (afferent), VII (efferent)
Also note that menace is a response not a reflex
What nerves does the PLR test? What about the dazzle reflex?
PLR: II (afferent), III (efferent)
Dazzle: II (afferent), VII (efferent)
What nerve does not need to function in order to elicit a postive oculocephalic reflex, though it is necessary to develop the reflex initially?
CN II
What tests are in the Minimum Data Base (for ophtho)?
Schirmer Tear Test
Fluoroscein Stain- for corneal ulcer, Jones, and Seidel
Tonometry
Which parts of the eye stain because the are hydrophilic?
Tear film
Stroma
(Epithelium and Descemet’s membrane don’t stain- hydrophobic)
T/F: A positive Jones Test demonstrates nasolacrimal patency, but a negative test does not necessarily prove nasolacrimal obstruction.
True
Should you perform tonometry to measure intraocular pressure before or after pupil dilation with tropicamide? What is the measurement in (unit)? What do pressures >25 with vision loss indicate? What does low pressure indicate?
Before
mmHg
High= Glaucoma
Low= Uveitis
N= 10-25mmHg
What is the arrow indicating?
A disrupted specular reflection
Aqueous flare is pathognomic for what disease process?
Uveitis
What is the term for a congenitally small and malformed globe?
Microphthalmos
What is the term for an acquired shrunken globe, most often from severe or chronic inflammation?
Phthisis bulbi
What is the term for anterior displacement of the globe such that the eyelids are caught behind the equator of the globe?
Proptosis
T/F: The boney orbit is part of the adnexa.
True
T/F: Cats and dogs have open orbits with an orbital ligament which forms the lateral boundary of the orbital rim.
True
(Horses and ruminants have closed orbits)
Relative to skull size, does the orbital ligament span a greater or shorter portion of the orbital rim in brachycephalic dogs?
Greater
(Orbit is much shallower)
What disorder of globe position is commonly associated with third eyelid protrusion, facial swelling, soft palate bulging, fever and pain when opening the mouth?
Exophthamos - abnormal protrusion of eye from orbit
What is the single most common mechanism that causes exophthalmos? What are 2 conditions in the dog that commonly cause this?
Orbital volume imbalance
Orbital neoplasia (no pain) and orbital cellulitis/abscess (pain)
What is the enlargement of the globe due to glaucoma?
Buphthalmos
What is the difference between enucleation and exenteration?
Enucleation= removal of eye
Exenteration = removal of eye + all orbital contents
What’s wrong here? What clinical signs are commonly associated with this condition?
Enophthalmos (abnormal recession of the eye within the orbit)
CS: uni-or bilateral facial muscle loss, third eyelid protrusion, entropion
What are the three common mechanisms of enophalmos? Also give one common cause of each of these.
- Orbital volume imbalances: Dehydration, emaciation/cachexia, myopathies, space occupying lesions anterior to globe
- Active globe retraction: Pain (skeletal muscle (retractor bulbi))
- Passive glove retraction: Horner’s Syndrome
What is strabismus?
Deviation of one or both eyes, so both eyes are not directed at the same object
What are some poor prognostic indicators for globe retention following proptosis?
Rupture of the eye
Hyphema
Orbital fractures
Poor owner compliance
What is the fibrocartilagenous layer of the eyelid that contains the meibomonian glands? What do the meibomonian glands produce?
Tarsus
Lipid/Sebum, outermost layer of the 3 layer tear film
What is dropping of the eyelids called? What is incomplete eyelid closure called?
Ptosis
Lagophthalmos
What is the condition called in which the eyelid margins roll in such that hairs are touching the ocular surface?
Entropion
What is the outward rolling of the eyelids called?
Ectropion
What is the term for squinting involuntarily or excessively?
Blepharospasm
What is the surgical procedure in which the eyelids are sutured together?
Tarsorrhaphy
What is it called when hairs growing on normal skin reaches the corneal and/or conjunctival surface (for example from the nasal folds in brachy breeds)?
Trichiasis
Which is the correct order from the outside to inside of the eyelid?
a. Skin - Tarsus and Meibomian glands - Muscle- Conjunctiva
b. Tarsus and Meibomian glands - Muscle- Conjunctiva- Skin
c. Skin - Muscle- Tarsus and Meibomian glands - Conjunctiva
c. Skin - Muscle- Tarsus and Meibomian glands - Conjunctiva
What is the main function of eyelid skin?
Sensory protection
Which muscle(s) close(s) the eyelids? Which muscle(s) open(s) the upper eyelid?
What does dysfunction of those muscles cause?
Close- Orbicularis oculi
Dysfunction= Lagohthalmos
Open upper- Levator palpebrae superioris, Mueller’s Muscle
Dysfunction= Ptosis
Entropion is an abnormal relationship of the eye in relation to the eyelids. What must you identify before treating this?
The cause of the imbalance
Permanent correction of anatomic entropion may not ne necessary until _____ months of age.
6-9
How can anatomic and blepharospasm entropion be differntiated? Why is this important to do before treating?
Use proparacaine drops to remove ocular pain which induces blepharospasm.
If you fail to assess the spastic component it can lead to overcorrection and ectropion
What surgery is the permanent correction for entropion?
Modified Hotz-Celus (rolls out eyelid)
Clinical signs of Horner’s syndrome are due to disruption of three target sites of the sympathetic nerve. What are these?
Upper eyelid- Mueller’s muscle
Iris- Iris dilator muscle
Periorbital cone- Circumferential smooth muscles
What is the most common cause of Horner’s?
Idiopathic- Post ganglionic
What is used to diagnose Horner’s syndrome?
Dilute phenylephrine (0.1%) 1 drop OU
What are the arrows indicating? How is it treated if it is causing problems? What else is that treatment used for?
Distichia
Tx: Cryoepilation (followed by plucking hairs out)
Often requires multiple treatments
Also used to treat ectopic cilia
T/F: Canine eyelid tumors are usually benign while cat eyelid tumors are usually malignant.
True
Most common in dog= meibomian gland adenoma
What are the 4 key concepts of the closure of eyelid margin defects?
- Limited debridement
- Closure must be perfect - use figure 8 suture pattern at margin
- Avoid full thickness suture bites
- Tarsus = holding layer
What will an untreated prolapsed gland of the third eyelid (Cherry eye) cause?
Chronic conjunctivitis
Keratoconjunctivitis sicca
What are the 2 common techniques to treat a prolapsed gland of the third eyelid?
Morgan pocket technique
Orbital tacking
What is the area where the palpebral conjunctiva meet the bulbar conjunctiva?
Conjunctival fornix
What is the common response to ocular irritation resulting in the overproduction of tears?
Epiphora
What do you call a permanent adhesion between the conjunctiva and the cornea?
Symblepharon
What are the non-perfused corneal blood vessels that provide evidence of previous keratitis?
Ghost vessels
What is chemosis?
Edema of the conjunctiva
What test do you use when you suspect KCS?
Schirmer Tear Test
What are the blue arrows pointing at? What does the presence of these indicate?
Lymphoid Follicles (on the palpebral surface of the 3rd eyelid)
Indicate primary conjunctivitis
Blepharospasm, epiphora, mucoid discharge, and hyperemia in a young dog with atopy, indicates what disease process?
Allergic conjunctivitis
In addition to treating the underlying cause, how do you treat allergic conjunctivitis?
Topical anti-inflammatories
e.g. Steroid (Neomycin-Polymycin-Dex), NSAID (Diclofenac 0.1%), T-Cell Inhibitor (Cyclosporin 0.2%)
What are the 3 layers of tear film? What are the 3 main funcitons?
Layers: Lipid/oil (Meibomian glands), Aqueous (lacrimal gland of 3rd eyelid), Mucinoid (innermost; Conjunctival goblet cells)
Functions: Nourish, Cleanse, Protect the ocular surface
What is the most common cause of KCS? What canine virus is associated with KCS?
Immune-Mediated destruction
Distemper
_______ KCS is an aqueous deficiency. It is diagnosed with clinical signs and when the STT is _____mm/min.
Quantitative
<15mm/min
Qualitative KCS is ____ or ____ deficiency. It is diagnosed with clinical signs and a STT _____ mm/min.
Lipid
Mucin
>/=15 mm/min
What dog breeds are associated with KCS?
Toy breeds
Brachycephalic breeds
Cocker Spaniels
T/F: KCS is often bilateral.
True
These are images of an eye affected by KCS. List the pathologies you can see.
Hyperemia
Mucopurulent discharge
Severe superficial neovascularization
A dog with severe mucopurulent discharge requires fluroescein staining. What must you do before applying the stain?
Wash away all discharge (so you don’t miss the lesion)
What part of the cornea commonly shows signs of keratitis and why?
Dorsal cornea
Remaining tear film protects the ventral cornea (gravity)
What is the treatment for the majority of KCS cases? How long is the course of treatment?
Topical cyclosporin (Optimmune)
Treatment is lifelong - controls but does not cure
What are the 4 objectives of KCS treatment?
- Replace tears (Artifical tears)
- Stimulate more tears (Cyclosporin)
- Anti-inflammatory therapy (Cyclosporin)
- Antibiotic therapy (Temporary)
What is the most common cause of feline conjunctivitis and keratitis? Why?
Feline Herpesvirus
The virus has epithelial tropism
What form of herpesvirus disease becomes reactivates due to environmental stress?
Recrudescent disease
What are 2 specific and 2 very specific FHV-1 clinical signs?
Specific: URI (more common with primary infections), Hyperemia
Very specific: Conjunctival and possible corneal epithelial ulceration (Dendritic ulceration= pathognomic), Symblepharon
T/F: If you observe conjuctivitis and evidence of present of historic keratitis, then consider FHV-1 over other causes of feline conjunctivitis.
True
What is the treatment for FHV-1?
Antiviral therapy: Topical cidofovir, Oral famciclovir
Supportive care (for ulceration): Topical erythromycin
What obligate intracellular bacteria causes conjunctivitis in young and/or stressed cats?
Chlamydia
(2nd most common cause of conjunctivitis behind FHV-1)
What is the most specific clinical sign associated with chlamydial conjunctivitis?
Chemosis
(Chemosis is for Chlamydia)
What will cytology with chlamydial conjunctivitis reveal?
Intracytoplasmic inclusion bodies
T/F: Chlamydial conjunctivitis causes corneal or conjunctival ulceration.
False!