Exam 2: Ophthalmology Flashcards
A condition in which the eyelid (usually the lower lid) folds inward. It is very uncomfortable, as the eyelashes constantly rub against the cornea and irritate it
Entropion
How is entropion treated?
Inject saline into eyelid and suture
with simple interrupted sutures
A full-thickness defect in the eyelid
Eyelid coloboma
What type of surgical technique is used for
removal of squamous cell carcinoma near the eye?
Sliding Flap technique and Burow’s triangles
There are no blood vessels in a normal healthy ______
cornea
Corneal stroma is made of collagen
arranged in a _______ fashion
to make it transparent
parallel
Name the layers of the cornea from outermost to innermost
Tear film
Corneal epithelium
Corneal stroma
Descemet’s membrane
Endothelium
This layer of the cornea is the thickest
and is composed of collagen arranged in a parallel manner
Corneal stroma
The innermost layer of the cornea,
the endothelium is _____ layer thick
1
Inflammation of the cornea is known as
Keratitis
What are the clinical signs of keratitis (corneal inflammation)?
Blepharospasm
Epiphora
Corneal edema
Corneal opacity
What type of block can you use to
inhibit blepharospasm in a horse?
Infraorbital block of the frontal nerve
Squinting of the eye due to pain is known as
blepharospasm
Why does the eye appear cloudy when corneal edema is present?
fluid in the stromal area causes collagen fibers to
be disorganized, resulting in the cloudy appearance
What test is used to diagnose keratitis?
Fluorescein test
What layer of the cornea is stained with
the fluorescein test?
Stroma
In normal corneal healing,
the cornea heals via this mechanism
Cell Sliding
Why does a corneal ulcer form?
Bacteria invade an epithelial defect in the cornea
causing tissue destruction and eventually
corneal perforation
What can the pattern of corneal vascularization tell you?
Depth of corneal ulcer
If you see corneal vascularization in a
circular or branching pattern,
how deep is the ulcer?
Superficial
What type of corneal vascularization pattern
do you expect to see in cases of a deep ulcer?
STRAIGHT pattern
Upon corneal inspection, you see
anastomosis of circular branching patterns and straight patterns
in corneal vascularization.
What does this tell you?
The problem is CHRONIC
________ swabs are used to culture
infections of the cornea
because cotton swabs have enzymes that can
mask some infections
synthetic
What surgical technique is used to treat
and undermined/deep corneal ulcers
after swabbing and trimming with a curette?
Conjunctival pedicle flap
brings more blood vessels to the area to help heal
You see an opacity and stain it with fluorescein, but there
is no uptake of the dye. The epithelial surface is uneven.
What is your dx?
Stromal Infection
What causes an iris prolapse (Staphyloma)?
An infection that is too deep ruptures into the anterior chamber.
The iris washes anteriorly, meaning it is pulled
against the cornea to plug the hole.
NEVER TOUCH THE IRIS- bleeds profusely
an inflammatory condition of the intraocular cavities (ie, the aqueous and/or vitreous humor) usually caused by infection
Endophthalmitis
How is Endophthalmitis treated?
exenteration of the eyeball (complete removal)
Lens luxation occurs when the lens capsule separates 360° from the zonules. This can eventually lead to
_________ formation
cataract
How is lens luxation treated?
Lens extraction
Describe what happens post-op lens extraction
Phthisis bulbi (a shrunken, non-functional eye) occurs.
Hyaluronic acid is used to fill the anterior chamber
This condition is known by all of the following names:
Uveitis
Iridocyclitis (iris inflammation)
Periodic ophthalmia (conjunctivitis, eye inflammation)
Moon Blindness
Equine Recurrent Uveitis
Equine Recurrent Uveitis is also known as
Moon Blindness
What is the most common cause of blindness in horses?
Moon Blindness (Equine Recurrent Uveitis)
What 3 components comprise the uvea?
Iris
Ciliary Body
Choroid
Inflammation of the entire vascular tunic of the eye
Uveitis
Moon Blindness (Equine Recurrent Uveitis)
is common in this breed of horses
APPALOOSAS
(Moo**n-Appal**oosas)
The prevalence of Moon Blindness (Equine Recurrent Uveitis) is _____% of all horses
12%
What are the clinical signs associated with
Equine Recurrent Uveitis/Moon Blindness?
PAIN (acute)
Photophobia, Blepharospasm, Lacrimation
Conjunctivitis
Hypopyon (inflammatory cells in the anterior chamber of the eye)
Miosis (pupil constriction)
Posterior Synechiae
is seen in ________ cases of
ERU/Moon Blindness
chronic/recurrent acute
eye condition where the iris adheres to the lens
posterior synechiae
What is going on with this eye?
Posterior Synechiae
(caused by ERU/moon blindness)
After the acute phase of ERU/moon blindness,
the eye is dilated using _______
which tears the iris from the lens and causes black dots
characteristic of posterior synechiae
Atropine
How is ERU/moon blindness diagnosed?
Ultrasound to look at posterior structures
especially retinal detachment
What medications are used in the treatment of
ERU/moon blindness?
Analgesics- phenylbutazone
Mydriatics (pupil dilation)- atropine
Topicals- corticosteroids
What surgical method is used in the treatment of
ERU/moon blindness?
Vitrectomy (removes floaters)
What tools are required to perform a Vitrectomy?
Vitreous cutter and suction
Eye prosthesis
What are “floaters”?
Inflammatory by-products in the vitreous humor
