Cornea & Sclera 1,2 & 3 & Eye exam/ Diagnostics

Question 1

What is the normal state for the corneal stroma?

Answer 1

avascular

Question 2

What accounts for about 90% of thickness and is arranged in a lamellar collagen arangment?

Answer 2

Corneal stroma

Question 3

What is the function of the corneal endothelium?

Answer 3

Pump fluid out of the cornea

Question 4

What is the normal state for the cornea to be in?

Answer 4

Dehydrated

Question 5

Vascularization in corneal pathology? (2)

Answer 5

Superficial disease= branching blood vessels
Intraocular disease= more vessels that are deeper in the cornea

Question 6

What are 2 specific congenital corneal disorders?

Answer 6

Corneal dermoid
Persistent Pupillary Membrane

Question 7

Corneal Dermoid (5)

Answer 7

1) Usually arises from the limbus
2) Embryologic defect
3) misplaced skin containinng hair follicles
4)Irritating and cosmetic
5) Doesn’t regrow after surgery

Question 8

Persistent Pupillary Membrane (PPMs) (4)

Answer 8

1) absorption of the pupillary membrane is incomplete as a fetus and shred or strands remain
2) Arise from the surface of the iris
3) No significant change in iris mobility
4) Nothing to be done about it

Question 9

What is corneal ulceration?

Answer 9

Full thickness loss of epithelium

Question 10

What are the clinical signs/findings associated with corneal ulceration? (4)

Answer 10

1) Blepharospasm/epiphora
2) Corneal edema (localized)
3) Conjunctival hyperemia/chemosis
4) Variable ocular discharge

Question 11

What are the specific causes of delayed corneal healing? (6)

Answer 11

1) corneal fixation
2) unresolved source of corneal abrasion
3) Keratoconjunctivitis sicca
4) Exposure keratitis
5) Neurotrophic keratitis
6) SCCED

Question 12

What are the risk factors for ulcer progression? (5)

Answer 12

1) Is tear production normal?
2) Can/does animal blink normally?
3) Brachycephalic breed/conformation exophthalmos?
4) Adnexal abnormalities?
5) Does ulcer appear infected?

Question 13

What complications are associated with Corneal Ulceration? (4)

Answer 13

1) Secondary infections
2) Stromal collagenolysis
3) Uveitis
4) Corneal perforation

Question 14

What are the descriptive classification of corneal ulcers? (3)

Answer 14

1) Superficial
2) Stromal (mid or deep)
3) Descemetocoele

Question 15

How do all ulcers start?

Answer 15

As acute superficial ulcers that will heal

Question 16

What is the defining feature of a mid-stromal ulcer?

Answer 16

Maybe some scaring but visual and will heal

Question 17

What is the defining feature of a deep-stromal ulcer?

Answer 17

More scaring than a mid- stromal ulcer but still visual and will heal

Question 18

What is the defining feature of a descemetocoele?

Answer 18

Translucent center in the cornea, not going to heal/fill in will require surgery

Question 19

What is a chronic superficial ulcer?

Answer 19

A superficial ulcer that is not healing appropriatly

Question 20

What are the diagnostics performed to determine if it is a corneal ulcer? (5)

Answer 20

1) search for underlying cause
2) Schirmer tear test
3) Corneal culture
4) corneal cytology
5) Fluorescien stain

Question 21

What are the goal of therapy for a corneal ulcer? (4)

Answer 21

1) Prevent/control infection
2) Prevent/control collagenolysis
3) Increase patient comfort
4) Promote healing

Question 22

What are the indication for surgical therapy involving a corneal ulcer? (4)

Answer 22

1) SCCED (spontaneous chronic corneal epithelial defect)
2) Progressive corneal ulceration
3) Deep stromal ulceration or descemetocoele
4) Keratomalacia (melting ulcer)

Question 23

Conjunctival flaps (4)

Answer 23

1) Mechanical support
2) Immediate blood supply
3) Source of fibroblasts
4) Source of epithelial cells

Question 24

What is the clinical appearence of SCCED (spontaneous chronic corneal epithelial defect)? (6)

Answer 24

1) Superficial, non-healing ulceration
2) No identifiable underlying cause
3) Non-infected
4) Loose epithelial lip surrounding ulcer
5) Variable vascularization
6) Variable ocular discomfort

Question 25

What is the treatment options for SCCED? (4)

Answer 25

1) Keratotomy 2) Manage as a superficial ulcer until healed 3) +/- 3rd eyelid flap 4) +/- contact lens

Question 26

What sort of treatment should not be done for SCCED?

Answer 26

Corneal debridement is NOT recommended

Question 27

What is the classic early corneal ulceration lesion associated with feline herpesvirus (FHV-1) keratitis?

Answer 27

Dendritic ulcers/erosion Rose bengal ulceration

Question 28

Canine herpesvirus corneal ulceration? (3)

Answer 28

1) Ubiquitous infection, but rare cuase of corneal disease 2) Dendritic ulcers or non-ulcerative inflammatory disease 3) commonly seen in immunosuppressed dogs

Question 29

Infectious Bovine Keratoconjunctivitis (IBK) (4)

Answer 29

1) Moraxella bovis 2) most common bovine ocular disease 3) highly contagious organism w/ significant economic impact 4) mechanical vector (face fly) or direct contact

Question 30

What are the ocular lesions associated with IBK? (5)

Answer 30

1) Corneal ulceration; maybe severe leading to proliferation 2) Conjunctivitis 3) Blephrospasm 4) Photophobia 5) epiphora/mucopurulent discharge

Question 31

Corneal Foreign body (3)

Answer 31

1) Removal mandatory 2) Potential for perforation 3) surgical intervention in select cases

Question 32

Corneal Abscess (5)

Answer 32

1) uncommon 2) intrastromal cellular accumulation 3) infected vs. sterile 4) must vascularize to heal 5) cannot drain it

Question 33

Pigmentary Keratitis (3)

Answer 33

1) NOT a specific disease 2) a result of underlying condition causing chronic irritation 3) most common/ severe in brachycephalic dogs

Question 34

Immune-mediated keratitis (4)

Answer 34

1) Idiopathic condition 2) Typically characterized by vascularization, edema, variable inflammatory cell infiltrate 3) Responsive to topical immunosupressive medication 4) Long term treatment usually required

Question 35

Chronic Superficial Keratitis (Pannus) (3)

Answer 35

1) German Shepherds and crosses 2) Exposure to UV radiation 3) Clinical signs bilateral

Question 36

What are the clinical signs for Chronic Superficial Keratitis (Pannus)? (3)

Answer 36

Bilateral 1) Corneal vascularization/pigmentation (from lateral limbus) 2) Conjunctival hyperemia 3) Nictitan thickening/depigmentation (Plasmoma)-not always present

Question 37

4 classifications of Equine IMMK

Answer 37

1) Epithelial 2) Superficial Stroma 3) Mid- stromal 4) Endothelial: no blood vessels, edema

Question 38

Causes of Lipid Keratopathy (3)

Answer 38

1) Lipid dystrophy (bilateral: Inhereited/breed related 2) Lipid Degeneration: antecedent or active corneal/scleral disease 3) Lipid Keratopathy due to systemic lipid metabolism abnormalities

Question 39

Corneal Mineralization/ Calcification Keratopathy appearance/ clinical findings (2)

Answer 39

1) Typically a benign condition 2) Ulceration over densely mineralized tissue

Question 40

What are the causes of Corneal Mineralization/ Calcification Keratopathy? (3)

Answer 40

1) Age-related degenerative condition 2) Secondary to systemic calcium/phosphorous imbalance 3) Seen in horses w/ chronic ERU (band keratopathy)

Question 41

Endothelial Dystrophy/ Degeneration (5)

Answer 41

1) Abnormal corneal endothelial development 2) Compounded by age-related endothelial deneration 3) Progressively severe corneal edema 4)corneal bullae formation/rupture 5) Corneal ulceration

Question 42

Feline Corneal Sequestrum clinical findings (3)

Answer 42

1) Painful 2) Focal brown/black corneal discoloration 3) Variable corneal vascularization

Question 43

Feline Corneal Sequestrum etiology/pathology (3)

Answer 43

1) Chronic corneal ulceration 2) FHV-1 3) breed predisposition

Question 44

Neoplastic Cornoscleral Masses (3)

Answer 44

1) Primary corneal neoplasms are rare 2) Corneoscleral/corneoconjuncatival neoplasms are more common 3) Melanocytoma, Squamous cell carcinoma, hemangioma

Question 45

Non-neoplastic Cornosclereal Masses (2)

Answer 45

1) Inflammatory- episclerokeratitis 2) Epithelial inclusion cyst

Question 46

Episcleritis (4)

Answer 46

1) Sectorial scleral thickening 2) No corneal encroachment 3) Unilateral or bilateral 4) Self-limiting

Question 47

Nodular Granulomatous Episclerokeratitis (5)

Answer 47

1) Immune-mediated inflammatory condition 2) only seen in dogs 3) Non painful, raised cornoscleral mass 4) Responds to immunosuppressive medication 5) Surgical excision alone generally not helpful

Question 48

Diffuse Scleritis (4)

Answer 48

1) Usually bilateral 2) Painful condition 3) Secondary corneal, uveal & retinal disease common 4) Systemic immunosuppressive medication required to control

Question 49

"Oblique Illumination" (2)

Answer 49

1) Application of light @ various angles 2) Highlight subtle corneal opacities, determining depth, contours of ocular structures etc.

Question 50

"Coaxial Illumination" (2)

Answer 50

1) light angled with observer's line of sight 2) effective means of highlighting light obstruction opacities in eye

Question 51

Anterior Segment Magnification tools (4)

Answer 51

1) Head loupe (optivisor) 2) Direct ophthalmoscope 3) Otoscope without cone (2-3x magnification) 4) Slit lamp biomicroscope

Question 52

Distant Direct Ophthalmoscopy (4)

Answer 52

1) coaxial illumination technique 2) set at 0 diopters 3) work at arms length from patient 4) nuclear sclerosis vs. cataract

Question 53

Direct ophthalmoscope for magnified ocular surface structure exam (3)

Answer 53

1) set diopter setting at 15-20 D 2) move in towards area of interest until lesion comes into focus 3) limitation is small surface area that can be visualized in this manner

Question 54

Fundus Exam (2)

Answer 54

1) determine cause of vision loss 2) searching for evidence of systemic disease that may affect the retina

Question 55

Fundus Exam Technique (5)

Answer 55

1) Set lens power to 0 D 2) while looking through the ophthalmoscope, lean in towards patient until retina is in focus 3) adjust diopter focus wheel as needed 4) typically need to be within 2-3 cm from cornea 5) at this distance, fundus is typically in focus somewhere between +2D & -2D on focus wheel

Question 56

Direct Ophthalmoscopy Technique (2)

Answer 56

1) Use right eye to examine patient's right eye and use left eye to examine patient's left eye 2) Easiest to perform in dilated eyes

Question 57

Direct Ophthalmoscopy Image (5)

Answer 57

1) Highly magnified 2) Best opportunity to see fine detail 3) difficult to evaluate entirety of fundus: especially in peripheral fundus 4) hard to isolate/localize lesions due to eye movements 5) Image is an anatomic orientation

Question 58

Monocular Indirect Ophthalmoscopy (3)

Answer 58

1) Employs hand held light source 2) Finoff transilluminator held adjacent to observers eye 3) Direct ophthalmoscope

Question 59

Binocular Indirect Ophthalmoscopy (3)

Answer 59

1) Employs specialized headset 2) allows for stereoscopic image 3) frees both hands for manipulating lens & patient

Question 60

Basic technique for indirect ophthalmoscopy (3)

Answer 60

1) low level of illumination 2) obtain a tapetal reflection 3) position indirect lens into path of light in front of patient's eye to obtain fundic image

Question 61

Image for indirect ophthalmoscopy (3)

Answer 61

1) wide field of view 2) Virtual image 3) upside down and reversed

Question 62

Lens alignment for indirect ophthalmoscopy (2)

Answer 62

1) Lens should be held perpendicular to light beam 2) must maintain this alignment when looking at different areas of retina

Question 63

General tips for all forms of ophthalmoscopy (4)

Answer 63

1) retina is best view in a dark room 2) use lowest practical light intensity 3) appropriate restraint is very helpful 4) pharmacologic dilation whenever possible

Question 64

When is dilation contraindicated in an ophthalmoscopy exam?

Answer 64

If there is concern about glaucoma or lens instability

Question 65

Schirmer tear test (4)

Answer 65

1) measures tear production) 2) insert in lower eyelid (lateral) up to notch on strip 3) leave in place 1 minute 4) read immediately following removal: measures in mm/min

Question 66

Application Method Topical Fluorescein stain (2)

Answer 66

1) directly touching pre-moistened strip to conjunctiva 2) create fluorescein solution in syringe & apply drop to ocular surface

Question 67

Primary diagnostic use for Topical Fluorescein stain (2)

Answer 67

1) corneal ulcer detection 2) evaluating nasolacrimal duct patency

Question 68

Tonometry (4)

Answer 68

1) Measures IOP 2) Measured in mmHg 3) Topical anesthetic for Tonopen & Schiotz NOT Tonovet 4) Always measure both eyes