Ophthomology Flashcards
1
Q
What are the five required tools for ophthomology?
A
Good light source, schirmer tear test, fluorescein, tonometry, ophthalmoscope
2
Q
What do you need to know about your patient before even seeing it?
A
Signalment, history,
3
Q
What cranial nerves might be affected with Cavernous Sinus syndrome?
A
CN III, IV, V, VI
4
Q
Which species, cat or dog, has a shorter orbital ligament?
A
Cat, so it has more protection from the skull
5
Q
What type of dogs are most susceptible to ocular disease via damage to the orbital ligament, and why?
A
Brachiocephalic dogs. The orbital ligament is much shallower
6
Q
What are some signs you will see with exophthalmos?
A
3rd eyelid protrusion, facial swelling, soft palate bulging, pain when opening mouth, fever
7
Q
What are two most common causes of exophthalmos?
A
orbital neoplasia, orbital cellulitis/abscess
8
Q
T/F: orbital neoplasia is often benign
A
False, malignant, slowly progressive, non-painful
9
Q
T/F: orbital abscesses are often painful
A
True. acute onset
10
Q
What are the two approaches to treat orbital neoplasia?
A
Globe sparing (radiation, exploration, chemo)
Globe removal (enucleation, exenteration)
11
Q
What are the two approaches to treat orbital abscesses?
A
NSAIDs + antibiotics
Surgical intervention
12
Q
What are some clinical signs seen with enophthalmos?
A
facial muscular loss, third eyelid protrusion, entropion (eyelid facing inward)
13
Q
What are the three common mechanisms of enophthalmos?
A
Orbital volume imbalances (dehydration, emaciation, disease)
Active globe retraction (muscle retraction)
Passive globe retraction (horner’s syndrome, damage to sympathetic nerves)
14
Q
What is phthisis bulbi?
A
an acquired shrunken globe, from severe or chronic inflammation
15
Q
What is strabismus?
A
deviation of one or both eyes where both eyes are not directing the same object
16
Q
How can strabismus be acquired?
A
dysfunction of any rectus muscle of the eye. CN III (DVM), CN IV, CN VI
17
Q
What is proptosis?
A
Protrusion of the eye, where the eyelids are cause behind the equator of the globe.
18
Q
What is a commonly better prognosis for proptosis?
A
brachycephalic dogs, a few torn extraocular muscles torn, positive PLRs
19
Q
What is a commonly poor prognosis for proptosis?
A
Cats, dolichocephalic dogs, >3 extraocular muscles torn, hyphema, orbital fracture, ruptured eye
20
Q
T/F: Dogs with proptosis have a low chance of regaining their sight.
A
True. 75-80% will be blinded in that eye
21
Q
How would you treat proptosis?
A
Temporary tarsorrhaphy (suturing eyelids closed)
22
Q
T/F: Proptosis can lead to strabismus.
A
True. medial rectus is the shortest muscle and is easily torn.
23
Q
What’s another word for Meibomian glands?
A
Tarsal glands
24
Q
What are the four layers of the eyelid?
A
Skin, Muscle, Tarsus, Conjunctiva
25
What are the three muscles that are relevant for eyelid movement?
Orbicularis oculi (closes like zipper)
Levator palpebrae superioris, Muller's muscle (opens eyelid)
26
What is ptosis?
drooping of the eyelid
27
What is lagophthalmos?
Incomplete eyelid closure and globe coverage
28
What is the function of the tarsus of the eye?
It is the fibrous and glandular layer of the eyelid. Supports the Meibomian glands.
29
What do surgeons use the tarsus for?
It is the holding layer for eyelid closure
30
T/F: The bulbar conjunctiva is usually slightly more hyperemic than the palpebral conjunctiva.
False. Palpebral is more hyperemic than the bulbar.
31
What are the two types of entropion?
Anatomic, were eyelids are conformed to the eye.
Blepharospasm associated, where pain leads to retraction of the eyelid.
32
You see a 5 month old puppy with anatomic entropion. What are some options of treatment?
Temporary correction via sutures. Leave alone and it may fix itself in a few months
33
What can acquired anatomic entropion lead to?
Enophthalmos, and blepharospasm (vicious cycle)
34
How can you differentiate between anatomic and blepharospasm entropion?
Local anesthetic in eye (proparacaine) will relieve the pain-induced blepharospasm
35
What are some temporary corrections for entropion?
Viscous lubrication, eyelid tacking, partial temporary tarsorrhaphy
36
What is the permanent correction for entropion?
Modified Hotz-Celsus
37
What are the common causes of ectropion?
iatrogenic (too much entropion correction)
hereditary
38
T/F: ectropion requires a lot more treatment than entropion
False.
39
What is the surgical procedure used for ectropion?
Lateral eyelid wedge excision
40
What are the 4 common causes of lagophthalmos?
1. ) Breed
2. ) Exophthalmos
3. ) Buphthalmos
4. ) CN V/CN VII dysfunction
41
What are the ocular signs seen with sympathetic denervation?
(Horner's syndrome)
| Miosis, enophthalmos, protrusion of the 3rd eyelid, ptosis
42
How does Horner's syndrome cause ptosis and miosis?
Lack of tone in the Muller's upper eyelid muscle and pupillary dilator muscle respectively.
43
Most commonly, how do you approach treatment for Horner's?
You don't. It's typically idiopathic and resolves itself
44
Does Horner's usually affect post- or pre-ganglionic nerves?
Post-ganglionic.
45
How do you diagnose Horner's?
Phenylephrine 1% into the eye.
Normal - 60 minutes to dilation
Post-ganglionic - 20 minutes
Pre-ganglionic - 40 minutes
46
What are the three abnormal hair conditions that have clinical significance?
1. ) Trichiasis
2. ) Disctichiasis
3. ) Ectopic Cilia
47
What is trichiasis?
Normal hairs reach into the eye and cause irritation to the surface
48
What is a surgical treatment used on brachycephalic breeds with trichiasis?
Medial canthoplasty
49
What is distichia?
Cilia emerge from the Meibomian glands
50
When would you want to treat for distichia?
If it is causing corneal/conjunctival disease
51
What are the treatment options for distichia?
Cryotherapy. Pluck the hair, then freeze
52
What is something to be cautious about with cryotherapy?
Eyelis depigmentation and necrosis
53
Which of the eye hair abnormalities leads to severe pain and corneal disease, that also waxes and wanes through the hair life cycle?
Ectopic cilia.
54
How would you treat ectopic cilia?
Cryotherapy
55
T/F: Canine eyelid tumors are typically more malignant than feline eyelid tumors.
False.
56
What is the most common eyelid tumor in dogs?
Meibomian gland adenoma/melanocytoma
57
What is the most common eyelid tumor in cats?
SCC
58
What are the three questions to ask yourself when dealing with canine eyelid tumors?
Is it causing irritation? How big is it? Where is it?
59
How would you treat a canine eyelid tumor? (two methods)
Debulk and cryotherapy
Complete excision
60
What are four key concepts of closing the eyelid during surgery?
1. Limit the debridement
2. closure must be a perfect figure 8 suture pattern
3. avoid full thickness bites
4. tarsus is the holding layer
61
What is blepharitis?
Inflammation of the eyelids
62
What is a chalazion?
A type of blepharitis due to enlargement of the meibomian gland from a blockage of the duct
63
How do you treat a chalazion?
Warm compress, surgical draining via incision, topical antibiotics
64
What is a hordeolum? Meibomianitis?
Bacterial infection of a meibomian gland. Meibomianitis involves multiple glands.
65
How would you treat a bacterial blepharitis case?
Systemic antibiotics, topical antibiotics/steroid, warm compress
66
How do you diagnose immune-mediated blepharitis?
Biopsy and cytology
67
T/F: Cherry eye is not commonly an emergency nor painful.
True
68
What does the third eyelid cartilage do?
Gives structure and shape, and supports the third eyelid gland.
69
What is another way of saying 'prolapsed gland of the 3rd eyelid'?
Cherry eye.
70
When is the only indication to completely remove the third eyelid gland?
Neoplasia.
71
What are the two treatments for cherry eye?
Morgan pocket technique, orbital tacking.
72
What is one important thing to think about when suturing up a cherry eye with the morgan pocket technique?
Do not fully close the incision. The gland still needs to drain its secretions, or a cyst may form
73
How can you treat eversion/scrolling of the third eyelid?
Excise the deformed cartilage, thermal cautery to kink/contract the cartilage.
74
What are some normal ocular conjunctival variations between each patient?
Encircling of the third eyelid (more some than others
Prominent episcleral vessels
Pigment
75
Where are the lymphoid follicles of the eye typically located?
On the bulbar surface of the third eyelid.
76
Where are the episceral vessels in relation to the conjunctival vessels?
They are deeper into the eye, also larger
77
What does conjunctival hyperemia suggest about the eye?
There is some superficial irritation (conjunctivitis, corneal ulcers, KCS)
78
What does episcleral injection suggest about the eye?
Deeper inflammation and congestion than conjuncival hyperemia.
79
T/F: You do not often see both hyperemia and episcleral injection at the same time
False. Commonly present together
80
What is the most common cause of conjunctivitis?
Keratoconjunctivitis sicca
81
What are some clinical signs of a patient with allergic conjunctivitis?
Blepharospasm, epiphora, mucoid discharge, hyperemia, lymphoid follicles
82
T/F: Allergic and viral conjunctivitia have the same clinical signs
True
83
How do you treat primary conjunctivitis?
Treat underlying cause, topical anti-inflammatory (NSAID, steroid), Optimmune (cyclosporine)
84
What are the most common causes of feline conjunctivitis?
Herpes, eosinophilic keratoconjunctivitis, chlamydia, mycoplasma, calicivirus
85
How many cats (percentage) are exposed to FHV-1?
100%
86
How many cats (percentage) are persistently infected by FHV-1?
80%
87
What are the two forms of herpes in cats?
Primary disease, then recrudescence (break out).
88
T/F: It is easy to diagnose and treat FHV-1
False! It's hard!
89
What do you see with kittens that are infected with FHV-1?
Upper respiratory tract infection, blepharospasm, epiphora, and mucoid discharge
90
What cranial nerve is affected by FHV-1?
Cranial nerve V - trigeminal
91
How can latent FHV-1 be reactivated?
environmental stress
| corticosteroids
92
What are some specific clinical signs for FHV-1?
Hyperemia and symblepharon (permanent adhesion between conjunctiva and cornea)
93
What corneal lesion is pathopneumonic for FHV-1?
Dendritic corneal ulceration (can see with fluorescein stain)
94
What disease should you consider when you see a cat with conjunctivitis and presence/history of keratitis?
FHV-1
95
How do you treat ocular FHV-1?
Antivirals - topical cidofovir, oral famciclovir
96
What do you see with feline eosinophilic keratoconjunctivitis?
Raised yellow/white plaques on the corneal/conjunctival areas
97
How do you diagnose feline eosinophilic keratoconjunctivitis?
Cytology. Just ONE eosinophils is diagnostic
98
How do you treat feline eosinophilic keratoconjunctivitis?
Immunomodulation (cyclosporine), anti-inflammatory, antiviral
99
What do you typically see with chlamydial conjunctivitis?
Chemosis!
100
T/F: Chlamydia does not commonly cause ulceration on the eye
True
101
How do you diagnose chlamydial/mycoplasma conjunctivitis?
PCR, cytology, rule outs of others
102
How do you treat chlamydial/mycoplasma conjunctivitis?
intracellular antibiotics (tetracycline, macrolides)
103
What is pathopneumonic for calicivirus conjunctivitis?
Oral ulcerations
104
Because definitive diagnosis is difficult, how would you treat feline conjunctivitis?
Give antibiotics first, then if it does not work, lean towards potential herpes virus -> antiviral
105
What are the three layers of the lacrimal system?
Lipid, aqueous, mucinous
106
What is the function of the lacrimal system?
Nourish, cleanse, protection of the ocular surface
107
Define quantitative keratoconjunctivitis.
Superficial corneal and conjunctival inflammation with low measurement of tear production (via Schirmer tear test)
108
What is the most common cause of quantitative KCS?
Immune-mediated destruction of the lacrimal tissue.
109
If the patient has quantitative KCS and a dry nose, what would your diagnosis be?
Parasympathetic nerve lesion of CN VII
110
What types of breeds are at most risk of KCS?
small, toy breeds
111
What are the clinical signs of KCS?
mucoid and mucopurulent discharge (from overproduction mucous from goblet cells with absence of aqueous layer), keratitis (superficial corneal vessels)
112
How do you treat KCS?
Cyclosporine (immunomodulator)
113
What do can you use to treat KCS if cyclosporine does not work?
Tacrolimus
114
What are the four objectives of KCS treatment?
Replace the tears
Stimulate more tears
Anti-inflammatory
Anti-biotics
115
What is the pathophysiology of neurogenic KCS?
Loss of parasympathetic innervation to the lacrimal gland and ipsilateral nostril (dry nose)
116
How would you treat neurogenic KCS?
pilocarpine (stimulates PNS)
117
What is the pathophysiology of canine distemper KCS?
viral destruction of the lacrimal glandular epithelium. Severe!
118
How would you surgically treat KCS?
Parotid duct transposition, use of saliva to replace tears. Test saliva pH
119
What produces the lipids of the outermost layer of the lacrimal system?
Meibomian glands
120
Define qualitative KCS.
superficial KCS with normal Schirmer Tear test results
121
What is the innermost layer of the lacrimal system?
Mucin layer.
122
What test can you use to test for mucin deficiency?
Tear Film Breakup Time (TFBUT). See how long it takes for fluorescein stain to break up on ocular surface. (Normal = 20 seconds)
123
What do you see you corneal fibrosis, and what causes it?
A whitish hazy appearance on the cornea, caused by qualitative KCS.
124
How do you treat qualitative KCS?
Replace the tears with (artificial tears), reduce inflammation (cyclosporine)
125
What are two things that lead to epiphora?
Poor drainage, blockage
126
What is the Jones test?
Tests presence of the nasolacrimal duct system
127
What is imperforate puntum?
When the punctal opening of the nasolacrimal duct is closed. Need surgical opening
128
What is a nasolacrimal disease and how can you treat it?
Dacryocystitis, treat with dacryocystotomy
129
What are the five most common categories of ulcerative keratitis?
Superficial uncomplicated ulcers, canine indolent ulceration, deep corneal ulcers, descemetoceles, perforations
130
What is the limbus?
Junction between cornea and sclera
131
What are the four primary layers of the cornea?
(superficial to deep)
| Epithelium, stroma, descement's membrane, endothelium
132
How does the cornea stay clear?
Avascular, non-myelinated nerves, dehydrated, ordered cell arrangement
133
How doest the cornea stay dehydrated?
Epithelium has a barrier to its tear film, endothelium has an active pump to get solutes out (water follows)
134
What are the steps to epithelialization?
1. ) Superficial ulcer
2. ) Hemidesmosomes degrade from under epithelial layer
3. ) Epithelial layer is able to slide
4. ) Rapid cell division at limbus
5. ) Epithelium slides to over ulcer
6. ) Epithelium is fixed and hemidesmosomes form again
135
What are the steps to stromal healing?
1. ) Stromal cells (keratocytes) transform into contractile cells
2. ) Cell fill up the defect
3. ) Ulcer epithelializes and heals
4. ) Stromal on the bottom heal, but cause disorganization and a scar
136
What is a facet?
When the epithelium heals over the remodeled stroma before it becomes level with the epithelial layer. Forms a dip/pool
137
T/F: Facets are painful
False
138
How do descemetoceles heal?
1. ) Vascular ingrowth is first required. (LONG TIME)
2. ) Scar will form
3) Epithelialization
139
What is another term for descemetocele facet?
Epithelialized descemetocele
140
What does a blue corneal opacity represent?
Edema
141
What are the two possible causes of edema?
Epithelial barrier disruption, endothelial barrier/pump disruption
142
How does the disruption of the epithelial barrier cause edema?
The tear film is able to enter the stroma due to the inability of the lack of the physical epithelial barrier
143
How could the cornea have generalized edema?
1. ) Large geographic epithelial/stromal defect
2. ) significant depth in damage of cornea
3. ) reflux uveitis
144
How could the disruption of the endothelial barrier lead to edema?
Focal loss of the sodium pump, generalized reduction in number and function
145
What is the term given to older patients with generalized edema?
Senile endothelial degeneration
146
What two things can cause the generalized reduction in function of the endothelial barrier of the cornea?
Glaucoma, uveitis
| hyperemia
147
What are the two sources for corneal neovascularization?
Superficial - granulation tissue and ghost vessels
Deep - ciliary flush
148
T/F: You can count the length of superficial vascularized vessels on the cornea to estimate how long they have been present.
True.
149
T/F: Superficial neovascularization does not cross the limbus.
False. It does
150
When would you see granulation tissue on the cornea?
When there is a chronic stimulant, typically with non-healing ulcers
151
What would the superficial vessels look like with granulation tissue?
Dense, raised collection of superficial vessels
152
What do you ghost vessels represent?
Empty, retracted blood vessels from a healed lesion.. Happens when the stimulus or irritant has been removed
153
What do white corneal opacities represent?
1. ) White blood cell infiltration
2. ) corneal fibrosis
3. ) minerals/lipids
154
What does a white blood cell infiltrate on the cornea mean?
Corneal infection with aggressive treatment required!
155
T/F: Corneal scars are painful.
False.
156
What causes corneal minerals/lipids in the cornea?
Corneal dystrophy - lipids
| Corneal degeneration - lipid or minerals
157
What do brown or black corneal opacities represent?
Epi/endothelial Pigment (melanin) or corneal sequestrum (cats)
158
What causes tan or greasy punctates in the cornea?
Keratic precipitates = cellular and fibrinous adhesions to the endothelium
159
What are the four brachycephlic risk factors for corneal ulcers?
1. ) ocular prominence
2. ) decreased corneal sensitivity
3. ) adnexal abnormalities
4. ) tear film abnormalities
160
What e-collars should you use with all ocular procedures?
Firm collars that extend beyond the nose
161
T/F: It is not safe to use topical steroids with corneal ulcers.
True
162
What affect do steroids have on ulcerative keratitis?
Delayed healing and enhanced corneal destruction
163
What are some causes of corneal ulceration?
Irritants, infection, trauma
164
What are the two categories of superficial corneal ulceration?
Uncomplicated/simple and complicated/complex
165
How long does it take for simple/uncomplicated superficial corneal ulcerations to heal?
7 days or less
166
T/F: Focal corneal edema may be present with simple/uncomplicated superficial corneal ulceration
True.
167
How do you treat simple/uncomplicated superficial ulcers?
E-collar*, broad spectrum antibiotics, atropine to keep the eyes dilated, recheck
168
What are some reasons as to why an ulcer will not heal appropriately?
1. ) There is an indolent ulcer
2. ) The underlying cause is not identified/treated
3. ) Infection
169
What is another term for indolent ulceration?
Spontaneous chronic corneal epithelial defect (SCCED)
170
What breed most commonly has indolent ulcers?
Boxers
171
What makes the indolent ulcer so difficult to heal?
The epithelium does not adhere to the stroma
172
What are the ways to treat an indolent ulcer?
Debride the area around the ulcer to encourage epithelialization.
Anterior stromal puncture (ASP)
Diamond burr debridement (DBD)
173
T/F: If the indolent ulcer is infected, it is not safe to perform an ASP or DBD.
True
174
What is the consequnce of performing ASP or DBD on cats with corneal ulceration?
Corneal sequestrum formations
175
Define collagenolysis and keratomalacia.
Enzymatic destruction of the corneal collagen leading to the softening and melting of the corneal stroma
176
What are the three most common bacteria responsible for deep stromal corneal ulceration?
Staph, Strep, Pseudomonas
177
What are the different variations of stromal ulceration?
Superficial stromal, mid stromal, deep stromal, descemetocele, perforation
178
How can you identify a stromal ulcer?
episcleral injection, defect in stroma, diffuse corneal edema, aqueous flare
179
What is the seidel test?
Tests perforation of the cornea by applying fluorescein and observing if it enters through any hole
180
What percentage of stromal loss is required before you recommend surgery for a corneal ulcer?
>50%
181
What are the surgeries that can be performed for corneal ulceration?
Conjunctival pedicle flap
360 degree conjunctival graft
182
How do you medically treat a deep corneal ulcer?
FREQUENT Antibiotics (q 1-2 hrs), anticollagenase therapy, pain management (NSAID)
183
What are the three indications for parenteral (oral/IV) antibiotics?
Vascularized ulcer, perforated ulcer, iatrogenic vascularization
184
What are the two forms of nonulcerative keratitis?
Pannus, pigmentary keratitis
185
What is Pannus? Explain.
Chronic Superficial keratitis.
Immune-mediated reaction to the epithelial surface.
186
T/F: Pannus is painful.
False
187
How do you treat Pannus?
Topical anti-inflammatory therapy (steroids, cyclosporine)
UV-light protection
188
What breeds are commonly seen with pigmentary keratitis?
Brachycephalic - pugs
189
How do you treat pigmentary keratitis?
Topical anti-inflammatory is mild.
Severe: medial canthoplasty
190
What muscles of the uvea are parasympathetic?
Iris sphincter muscles
191
What muscles of the uvea are sympathetic?
Iris dilator muscles
192
What are the function and components of blood-aqueous barrier?
Iris blood vessels and ciliary body prevent passage of proteins into the anterior chamber. Allows for clear media in the eye for vision
193
What are the functions of the uvea?
To produce aqueous solution for nutrient and waste, main a good blood-aqueous barrier, light regulation
194
Define dyscoria, anisocoria, anterior synechia, posterior synechia, peripheral anterior synechia, iris bombe
D - Abnormally shapred pupil
A - unequally sized pupils
AS - adhesion of iris to cornea
PS - adhesion of iris to lens
PAS - adhesion of iris to iridocorneal angle
IB - bulging of iris from poor passage aqueous from PS
195
What are persistent pupillary membranes?
Incomplete absorption of embryonic vascular tissue and mesenchymal strands
196
T/F:(Persistent pupillary membranes) PPMs are usually uncommon, cause disease, and are always bilateral.
False. Common, incidental, and uni/bilateral
197
What are some specific lesions seen with Uveitis?
Miosis, aqueous flare, hyphema, hypopyon, keratic precipitates, thickened iris, hyperemic iris, decreased IOP
198
What causes miosis in uveitis?
Prostaglandins cause pain and ciliary spasms, leads to iris sphincter contraction
199
What does aqueous flare lead to?
Increased turbidity of aqueous humor from inflammation and breakdown of barrier, leading to proteins and cells in the anterior chamber
200
What is considered normal intraocular pressure?
10-20 mm Hg
201
What are the effects of decreased IOP?
decreased AH production, increased uveoscleral outflow
202
What are some chronic signs of uveitis?
Dyscoria, Posterior synechia, Peripheral anterior synechia, iris hyperpigmentation
203
What are the consequences of long term chronic uveitis (sequelae)?
Cataracts, lens luxation, glaucoma, retinal detachment, phthisis bulbi
204
What are the two differentials of uveitis and how do you treat them?
Exogenous (treat primary issue and uveitis) and endogenous (hard to diagnose)
205
What are some tests you want to run for a dog with uveitis?
Thorough travel history, PE, CBC, Chem panel, urinalysis, thoracic radiographs, tick titers, fungal titers
206
If hyphema is present, what additional test would you want to run?
Coagulation panel
207
What are some test you want to run for a cat with uveitis?
Thorough travel history, PE, CBC, Chem panel, urinalysis, thoracic radiographs, FIV/FeLV, toxo titer, fungal titer
208
What are the two most common fungal infections in cats with uveitis?
Cryptococcus, histoplasmos
209
What medication is required in ALL uveitis treatment, regardless of infection/non-infection?
Anti-inflammatory therapy
210
T/F: Topical steroids and topical NSAIDs are allowed simultaneously
True
211
Can you use topical corticosteroids for uveitis treatment?
No, does not penetrate the corneal wall.
212
What should you rule out before giving systemic corticosteroids to treat uveitis?
Infection
213
What medication is used as a mydriatic?
Atropine 1%
214
T/F: Intraocular bacterial infections typically have a good prognosis
False
215
How do differentiate between a uveal cyst and a tumor?
Translumination. If light flashes in the mass, is most likely a fluid filled cyst
216
T/F: Most intraocular tumors in dogs are malignant.
False. Benign
217
T/F: Most intraocular tumors in cats are malignant.
True
218
What is the second most common uveal tumor in dogs?
Ciliary body adenoma/adenocarcinoma.
219
What is the most common uveal tumor in cats?
Feline diffuse iris melanoma
220
What are the two things to do with cats and potential uveal tumors?
Monitor!
Enucleation
221
T/F: Any color, shape, or size change in the uvea can be serious for the cat.
True
222
What is the most common secondary uveal tumor in both cats and dogs?
Lymphosarcoma
223
What is the basic function of the lens?
To focus light onto the retina to produce a sharp image
224
Define nuclear sclerosis.
When new lens cells and fibers are produced and the nucleus becomes compressed with age. Loss in ability to contract and relax shape
225
What does an eye with nuclear sclerosis look like?
Bluish-gray, pearly haze
226
T/F: Nuclear sclerosis patients have a loss of vision.
False
227
Define a cataract.
Any opacity of the lens of capsule.
228
T/F: Cataracts can cause a loss of vision.
True
229
How would you classify cataracts?
Age of onset, location within the lens, state of maturation, cause
230
Where would the nuclear vs the equatorial cataract be located?
Nuclear is in the center of the lens, equatorial is on the equator
231
What two methods do you use to examine cataracts?
Oblique - judges the position of opacities
| Parallax - decides depth of opacities
232
Case: You see an opacity in the lens move on the opposite direction of the animal's direction of sight. Where is the opacity?
Posterior part of the lens.
233
What are the four stages of cataracts?
Incipient, incomplete (immature), complete (mature), resorbing (hypermature)
234
How large is an incipient cataract?
235
T/F: You cannot see the tapetal reflection with incipient cataracts and vision is typically affected
False. You can see it and they can see!
236
T/F: You cannot see the tapetal reflection and vision is typically affected with incomplete cataracts
False!
237
How much of the lens is affected in a complete cataract?
100%
238
T/F: In a complete cataract, the tapetal reflection is not visible and the animal is blind.
True
239
What happens to the lens with resorbing cataracts?
It liquefies, and shrinks
240
What other disease of the eye do you commonly see with resorbing cataracts?
Uveitis
241
What happens to the lens in an intumescent cataract?
It swells up and gets larger
242
What endocrine condition commonly has association with intumescent cataracts?
Diabetes! (metabolic cataracts)
243
What is the most common cause of cataracts in dogs?
Inherited.
244
What is the most common cause of cataracts in cats?
Chronic uveitis
245
What breed of dogs commonly have inherited cataracts?
Boston Terriers
246
What is the pathophysiology of chronic uveitis in cats/horses?
Inflammatory mediators diffuse into the lens and alter its structure/metabolism, leading to aqueous humor production
247
What is the pathophysiology of metabolic cataracts?
Sorbitol accumulation in the lens, draws water from aqueous humor and changes in the lens
248
What enzyme is upregulated in diabetes that leads to the increase in sorbitol?
Aldose reductase
249
What early signs may you see in the lens of a diabetic cataract?
Clefting of the Y-suture
250
How do endogenous toxic cataracts cause disease?
Degenerating photoreceptors release toxic substances into the vitreous humor.
251
T/F: Senile cataracts impair vision
False.
252
How do you treat cataracts?
Medication - anti-inflammatories
Surgery - phacoemulsification
253
What is the only proven and effective cataract treatment?
Phacoemulsification - high frequency vibration emulsifies the cataract and is then removed via aspiration
254
What is pseudophakia and aphakia?
Presence (and absence) of an artifical intraocular lens after surgery
255
What are some factors to consider before doing cataract surgery?
Extent of visual defects, overall health of animal and eye, client commitment, animal temperament
256
When is the best time to refer an animal for cataract surgery?
ASAP!
257
What is a phacoclastic lens-induced uveitis (LIU)?
severe form of LIU associated with traumatic tears of the lens capsule
258
What is the phacolytic lens-induced uveitis (LIU?)
mild form of LIU associated with leakage of lens proteins
259
What should you expect with a red eye with a cataract?
Phacolytic lens-induced uveitis
260
What dog breed is most predisposed to lens luxation?
canine terrier breed due to their abnormal zonular ligament degeneration
261
What is the most common cause of lens luxation in cats?
Chronic uveitis
262
What are some early signs of lens luxation?
Iridodonesis/Phacodonesis (shaking of iris/lens)
263
How does glaucoma and buphthalmos cause lens subluxation?
The pressure in the eye stretches the lens zonules and tear them
264
T/F: Anterior lens luxation is an emergency
True.
265
What should you do to the eye of a dog with anterior lens luxation before sending it to the referral ophthomologist?
Mannitol, carbonic anhydrase inhibitors, NO miotics/mydriatics
266
How do you treat an anterior lens luxation?
Intracapsular lens extraction
267
How do you medically treat an anterior lens luxation, if surgrey is not possible?
Dilate the pupil, let the lens fall to the back of the eye, then dilate the pupil to trap it back in.
268
How does glaucoma cause disease?
Increased intraocular pressure leads to damaging of the optic nerve and retina, and loss of vision
269
T/F: Glaucoma is almost always due to impaired inflow.
False. Outflow
270
What are some common clinical signs associated with glaucoma?
```
Red eye - episcleral injection
Pain - blepharospasm
Cloudy - corneal edema
Mydriasis
Impaired vision
```
271
What are some clinical signs associated with chronic glaucoma?
retinal degeneration, blindness, buphthalmos, lens change, phthisis bulbi
272
Define phthisis bulbi.
End stage disease of the eye. Shrunken
273
How would you differentiate between buphthalmia and exophthalmia?
Check the IOP. Exophthalmia would be typically normal. Also check corneal diameter and for lens luxation
274
At what IOP reading should you start being suspicious of glaucoma?
>20 mm Hg
275
What IOP reading is sufficient evidence for glaucoma diagnosis?
>25 mm Hg, with clinical signs
276
What tonometry instrument measures indentation of the eye?
Schiotz tonometry
277
What tonometry instrument measures applanation of the eye?
TonoPen
278
What instrument measures rebound tonometry?
TonoVet
279
What is the benefit of using a TonoVet?
No topical anesthetic needed! even for cats!
280
Of the four readings, which is the correct IOP? 20 mmHg, 15 mmHg, 16 mmHg, 25 mmHg
15 mmHg (lowest is the best answer)
281
What is the most common primary cause of glaucoma?
Primary Angle Closure Glaucoma (goniodysgenesis)
282
What is the most common secondary cause of glaucoma?
Uveitis (do full work up)
283
What happens with goniodysgenesis that causes glaucoma?
decrease aqueous outflow from arrest iridocorneal angle
284
T/F: Animals with unilateral goniodysgenesis usually also develop glaucoma in the other eye as well.
True
285
What is the #1 treatment for primary open angle glaucoma/goniodysgenesis?
Latanoprost (prostagladin derivative). Increases uveoscleral outflow
286
When would you not want to use latanoprost to treat glaucoma?
If the glaucoma is secondary to uveitis. Use only for primary glaucoma!
287
What treatment do you use if latanoprost does not work?
Mannitol 20% with methazolamide, carbonic anhydrase inhibitors, pilocarpine (miotic)
288
What are the two glaucoma drugs to have above all others?
Latanoprost (all primary)
| Dorzolamide (all secondary, all cats)
289
What is the best long term therapy for cats?
Surgery, gonioimplant (increases outflow), ciliary body ablation (decrease production)
290
How effective is prophylactic therapy to prevent glaucoma in the fellow eye?
Very good, extends from 8 to 33 months before the other eye gets glaucoma
291
What medications are used for prophylactic therapy in glaucoma?
Betaxolol 0.5%
| Demarcarium bromide 0.125%
292
How would you treat glaucoma secondary to uveitis?
Aggressive therapy for uveitis, dorzolamide!
293
T/F: Feline glaucoma is often subtle and difficult to notice
True
294
How do you treat feline glaucoma?
Dorzolamide
295
What is aqueous misdirection syndrome and how do you treat it?
The aqueous humor is misdirected so that the lens/iris are shifted forward. Treat with dorzolamide, eventually enucleate
296
T/F: The sclera has both pigmented and non-pigmented areas to allow the tapetum to reflect.
False. The retinal epithelium does this, but may be entirely unpigmented.
297
T/F: Cats have myelinated optic nerve heads
False. Only dogs do.
298
What is a holangiotic retinal vascular pattern?
Blood vessels are distributed all throughout the retina
299
Merangiotic retinal pattern. Define it.
Localized vasculature in the retina. Rabbits
300
Paurangiotic retinal pattern. Define.
Poorly vascularized retina. Horses
301
Anangiotic retinal pattern. Define.
No blood in retina area. Hawks.
302
List some species that are atapetal.
Chincilla, blue-eyed dogs, pigs, humans, alpacas
303
What are the types of retinal hemorrhages that can be observed?
Pre-retinal, within nerve fiber layer, within the retina, sub-retinal
304
List some causes of retinal detachment
Retinal degeneration, vitreous disease, lens luxation, neoplasia, trauma
305
What are the types of retinal detachments?
focal, multifocal, complete, exudative, traction, rhegmatogenous
306
What is a common early sign of feline hypertensive retinopathy?
Exudative detachment
307
How do you treat exudative retinal detachment and feline hypertensive retinopathy?
antihypertensive therapy. the retina will then attach back on its own
308
How do you treat a partial rhegmatogenous retinal detachment?
Retinopexy
309
How do you treat a complete rhegmatogenous retinal detachment?
Re-attachment surgery
310
What can cause increased reflectivity of the tapetum lucidum?
Retinal degeneration/scarring, detachment
311
What can cause decreased reflectivity of the tapetum lucidum?
increased retinal thickness from folding, edema, effusion, infiltrates
312
What is progressive retinal atrophy? (PRA)
photoreceptor degeneration and gradual loss of vision
313
How do you treat PRA?
You can't.
314
What is a major finding in the fundus exam of a patient with PRA?
Narrowing and loss of retinal blood vessels, slow PLRs
315
What is sudden acquired retinal degeneration syndrome (SARDS)?
Sudden loss of vision from acute photoreceptor death
316
How would a fundus exam look on an patient with SARDS?
Normal.
317
What are the common conditions of animals with SARDS?
Older and fatter
318
What is feline central retinal degeneration?
Degeneration confined to elliptical area dorsolateral to optic nerve head.
319
What drug may cause retinal degeneration in cats?
Enrofloxacin.
320
What would you see in the fundus exam in a patient with active chorioretinitis?
Gray-white areas of edema or cellular infiltrate
321
What type of lesions are categorized in chorioretinitis?
Active and inactive lesions
322
What kind of lesions do you see with inactive chorioretinitis?
Scarring and flatness of the chorioretina
323
How do you treat chorioretinitis?
Anti-microbials, anti-inflammatory
324
What do you see in a patient with optic neuritis?
Hyperemia, peripapillary edema, associated retinal detachment and hemorrhage
PLR abnormalities
325
What is the main goal as a clinician when dealing with a blind animal?
Finding if its a result of an ophthomological or neurological disease.
326
What is the difference between peripheral and central blindness?
The visual pathway is shared with PLR in peripheral but not central blindness.
