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Ophtho (sophomore) > Cornea dzs (Plummer) > Flashcards

Cornea dzs (Plummer) Flashcards

1
Q

Corneal anatomy

A
  • Outermost epithelium
    • 6-10 cell layers thick
  • Stroma
    • 90% of corneal thickness
    • mostly collagen
  • Descemet’s membrane
    • BM of endothelium
    • Thickens with age
  • Innermost endothelium
    • Monolayer of cells
    • The pump
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2
Q

Corneal stroma

A
  • regular parrallel arrangement of collagen fibers
  • Keratocytes
  • GAGs
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3
Q

Corneal innervation

A
  • Anterior stroma
  • Decreased sensitivity can affect healing
    • brachycephalics
    • Sick foals
    • Diabetics
  • Protection
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4
Q

Functions of cornea

A
  • anterior structure for globe
    • front of fibrous tunic
  • protection of interior structures from injury/infection
  • Clear medium for vision
  • Refraction
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5
Q

Corneal clarity

A
  • Avascular
    • normal state
    • except manatees
  • Anhydrous
  • Regular arrangement of collagen fibers
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6
Q

Corneal opacification

A
  • Cellular infiltrate
  • FIbrosis
  • Pigment
  • Neovascularization
  • Edema
  • Mineralization/Lipid deposition
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7
Q

Cellular infiltrate

A
  • Yellow or white appearance to stroma
  • WBCs migrate in
  • Often indicative of infection
  • Complicated
    • ulcers
    • stromal abscesses
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8
Q

Hypopion

A
  • White creamy infiltrate in anterior chamber
  • Indication of intraocular inflammation
  • concurrent with anterior uveitis (I think)
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9
Q

Fibrosis

A
  • White-grey color to cornea
  • End result of healing response, scar
  • Irregular rearrangement of collagen lamellae following injury
  • Quiet appearance
  • No fluid
  • Minimal vessels
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10
Q

Pigment

A
  • Usually secondary to chronic irritation
  • Pigment migrates in from limbus
  • Usually located superficial cornea
  • Frequently develops in association with conjuctival grafts

*Chronic inflammation/chronic irritation = pigment

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11
Q

Vascularization

A
  • Blood vessels grow into cornea
  • May be deep or superficial
    • brush border: deep vessels
    • Long singular branches: superficial vessels
  • Frequently leak fluid into cornea
  • Any sort of inflammatory stimulus

*bluer colorizarion is edema instead of fibrosis

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12
Q

Edema

A
  • Fluid within corneal stroma
  • Occurs at different levels
  • May appear
    • patchy
    • focal
    • diffuse
  • can form bullae or vesicles
  • Blue appearance
  • Lesions
    • Ulcers
    • keratitis
    • endothelial decompensation
    • galucoma
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13
Q

Mineralization

A
  • Usually dystrophic, in association with a degenerative process
  • rarely metastatic
  • usually just underneath epithelium
  • Difficult to treat
  • lesions
    • corneal dystrophies
    • band keratopathy
    • chronic uveitis
    • topical steroids
  • Lipid dystrophies
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14
Q

Corneal ulcer

A
  • most common presenting ophthalmic condition
  • Defect in cornea with loss of tissue
    • scratch
    • defect
    • wound
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15
Q

Corneal ulcer classification

A
  1. Depth
  2. Etiology
  3. Response to therapy
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16
Q

Corneal ulcer

Depth

A
  • Superficial
  • Stromal
  • Descemetocele
  • Full-thickness - iris prolapse
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17
Q

Corneal ulcer

Etiology

A
  • Traumatic
  • Infectious
    • bacterial
    • fungal
  • Immune-mediated
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18
Q

Corneal ulcer

Response to tissue

A
  • Simple
  • Complicated
    • indolent
    • melting
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19
Q

Superficial ulcer

Response to injury

A
  • Eipthelial cell mitosis in basal layer only
    • thickness increases from 8-15 cell layers
  • After injury, mitosis stops, loss of attachments and cells migrate over wound
    • migration at 0.6 mm/day if no infection
  • Mitosis resumes after wound closure
  • Stem cells at limbus maintain fresh supply of mitotically active basal epithelial cells
    • 6 weeks for epithelial cells to reattach basement membrane to stroma
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20
Q

Stroma response to injury

A
  • re-synthesize and cross-linking of collagen
  • balance of resorptive remodeling and restorative repair by fibroblasts
    • resorptive remodeling
      • proteinases from bacteria, PMNs and corneal cells
  • PMNs appear around necrotic areas
  • Cells adjacent to wound edge transform
    • leads to accumulation of fibroblasts
  • Firbroblasts proliferate and produce collagen
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21
Q

Vascularization response to injury

A
  • Non-specific response to insult
    • infection
    • inflammation
    • degeneration
  • Can be
    • superficial
    • deep
    • focal
    • curcumlimbal
  • result from vascular cellular sprouting from perilimbal vessels
  • Ghost vessels
    • receded, deperfused vessels

*migrate about 1mm/day I think

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22
Q

TO REMEMBER about corneal wound healing

A
  • Corneal blood vessels move at about 1mm/day
  • WBC move in cornea at 8.6 mm/day
  • Epithelial cells move about 1mm/day
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23
Q

Corneal dzs

A
  • Congenital
    • Dermoids: normal tissue in abnormal locale
      • tx: supervicial keratectomy
  • Acquired
    • Ulcers
    • Trauma
    • Inflammation
    • Dystrophy
    • Degeneration
    • Neoplasia
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24
Q

Corneal ulcer principal strategies

A
  • Quick dx is difference between sight and blindness
  • Assume ulcers will get worse
  • Treat aggressively
  • Recheck often
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25
Q

Corneal ulcer

CS

A
  • Blepharospasm
  • Epiphora
  • Serous to mucopurulent d/c
  • Miosis d/t reflex uveitis
  • Corneal edema
  • Corneal vascularization
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26
Q

Corneal ulcer

DXs

A
  • Culture infected lesions before meds/drugs
    • aerobic
    • fungal (esp. horses)
  • Schirmer’s tear test (esp. SA)
    • unless eye is about to rupture
    • N: 15-25 depending on clinical scenario
      • should be higher if ulcerative
  • Fluorescein stain painful eyes
    • squinting
    • tearing
    • cloudiness
    • redness
    • droopy eyelashes
  • Cytology (esp. horses)
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27
Q

Corneal cytology

A
  • Topical anesthesia
  • end of scalpel blade/cytology brush
  • Diff Quick or Gram stain
  • Guides Tx choice and prognosis
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28
Q

Ulcerative Keratitis

A
  • Corneal epithelium: barrier against bacterial
  • Progression to deep stromal ulcer if
    • infection
    • epithelium unable to attach to stroma
    • delayed healing
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29
Q

Descemetoceles

A
  • Epithelium and stroma lost
  • very thin, fragile, prone to rupture
    • if rupture iris prolapse usually follows AqH and plugs hole
  • bulges to do AqH pressure
  • surgical ulcer
30
Q

Melting ulcers

A
  • Complicated stromal ulcer
  • Ulcers with active proteases
    • gray-ish gelatinous appearance
    • potentiated by topical corticosteroids
  • distinguish from corneal edema
    • corneal edema doesn’t usually distort ocular surface
31
Q

Melting corneal ulcer

Pathophys

A
  • Normal tear fluid contains soluble proteins
    • MMPs, NE
  • In injury imalance of degradation and rebuilding factors can happen
  • Target of therapy
    • MMPs and NE
32
Q

Infectious ulcers

A
  • Bacteria
    • Pseudomonas
    • Stretococcus
    • Staphylococcus
  • Fungi
    • Aspergillus
    • Candida
    • Fusarium
  • Virus
    • Herpes
33
Q

Identifying an infected ulcer

A
  • presence of cellular infiltrate
  • melting
  • degree of uveitis
  • delayed healing
  • positive cytology or culture
34
Q

Herpetic Dz

A
  • Cats
  • URI
  • Epiphora
  • Cytolytic
    • conjuctivitis
    • Ulcerative keratitis
    • Symbleparon
      • adhesions of conjunctiva
  • Immunopathologic
    • stromal keratitis
    • eosinophilic keratitis
    • sequestra
  • TX
    • topical antivirals
    • topical antibiotics
35
Q

Dendritic ulcers

A
  • Pathopneumonic for herpes virus infection
    • infects epithelial cells that cover nerves
36
Q

Goals of ulcer therapy

A
  • Sterilize wound bed
  • control secondary anterior uveitis
    • ALWAYS PRESENT
  • Slow collagen breakdown
  • Provide structural support
37
Q

Medical Treatment of Ulcers

A
  • Treat etiology
  • Broad spectrum antibiotics
  • Reduce tear protease activity
    • EDTA, Acetylcysteine
    • Serum
      • contains alpha-2 macroglobulin with anticollagenase activity
  • Treat Uveitis
    • Topical mydriatic
      • topical atropine (also stabilizes blood aqueous barrier)
    • Systemic NSAIDs
38
Q

Topical NSAIDS

A
  • Can use if MAIN PROB is uveitis
  • May potentiate keratomalacia
  • Systemic NSAIDs and atropine are preferred
39
Q

Antibiotics

A
  • Toxic to epithelial cells
    • use least toxic one indicated
40
Q

TX protocol for simple superficial ulcer

A
  • Triple antibiotic TID-QID
  • 1% atropine SID
    • colic in horses
  • +/- Serum QID
  • e-collar
  • recheck 2-3 days
  • Response
    • should take up less fluorescein and be less painful in 24-48 hours
      • if not consider a complicating factor - add serum
41
Q

TX protocol for stromal/complicated ulcers

A
  • Antibiotics based on cytology/C&S
  • Antifungals if indicated
  • Serum, EDTA or acetylcysteine q 1-4
  • Atropine TID
  • Systemic NSAIDS
  • +/- surgical stabilization
42
Q

Healing of complicated ulcers

A
  • observed healing from limbus in
    • clearing
    • blood vessels
  • Reduced stimulus for uveitis
    • pupil stays dilated easier
    • can reduce frequency of atropine admin
    • can decrease systemic non-steroidals
43
Q

Melting ulcers TX

A
  • aggressive
  • antibiotics initially q 1-2h
  • antifungals if indicated
  • atropine TID until dilated
  • Serum, EDTA or acetylcystein q 1h
  • Systemic NSAIDS
  • Analgesics
  • +/- surgical stabilization
    • keratectomy and conjunctival flap
44
Q

Anti-melting therapy

frequency of therapy

Making eyedrops

A
  • Gross melting
    • treat hourly
  • Prevention/to speed healing
    • use q2-6
  • Serum or plasma
    • Best and cheapest
    • pull blood and spin down in serum separator (Tiger top)
    • refridgerate
    • good for 8 days
  • EDTA (0.17%)
    • lavendar top tube, fill to line with sterile water
    • Chelates Ca and Zn
      • so they are unavailable for MMPs to use as substrate
  • N-acetylcysteine (5%)
    • 5 mL 20% mucomyst + 1.5 mL artificial tears
45
Q

Autologous Serum

A
  • prefered anticoagenase
  • contains
    • alpha -2 macroglobulin
    • nutrients to stimulate healing
  • maintain in sterile bottle
46
Q

Melting ulcer

healing progression

A
  • should show increase in stromal rigidity in the first 24 hours
    • if not structural stabilization by surgery
47
Q

Epithelialization can move in in …..

A

days

48
Q

Stromal filling can take

A

weeks

49
Q

Surgery generally indicated for

A
  • deep ulcers
  • desmetoceles
  • perforated Ulcers
50
Q

PK/CF surgery

A
  • Brings fibroblasts
  • vascularization
  • physical support
51
Q

Types of conj flaps

A
  • 360 degrees
  • hood
  • island
  • pedicle
  • bridge
52
Q

Iris Prolapse

A
  • Emergency
  • systemic antibiotics
  • general anesthesia and surgical repair of cornea
  • reposition or amputate
    • suture cornea
    • CF if needed
  • Topical antibiotic solutions
    • NOT OINTMENTS=vehicle is damaging to inside of eye
  • Topical atropine
53
Q

Other surgical options

A
  • Penetrating keratoplasty
  • corneal transplants
  • synthetic grafts
  • amniotic membrane grafts
  • keratoprostheses
54
Q

Corneal lacerations

A
  • Ability to repair depends on
    • length
    • damage to interior structures
    • involvement of limbus
  • Initiate systemic antibiotics
  • almost always require surgical tx
    • sx for all full thickness lesions
  • following tx like a serious corneal ulcer
55
Q

Corneal foreign bodies

A
  • Look at entire eye
  • Depth
  • Fibrin
    • fibrin in anterior chamber indicates full thickness breach
  • Remove and treat ulcer
56
Q

Non-healing ulcers

A
  • check eyelid position
    • lash abnormalities
  • Tear production
  • presence of foreign bodies
    • behind third eyelid
  • infection
  • no underlying problems
    • indolent/refractory
57
Q

refractory ulcers

A
  • AKA Indolent/’Boxer’ ulcer
    • also aged animals
  • Superficial corneal erosion with epithelial ‘lips’
    • epithelium rolled up and back at the edges
  • Chronic blepharospasm, epiphora, photophobia
  • Fluorescein diffuses uder epithelium
58
Q

Indolent ulcers

Pathophys

A
  • Defect in hemidesmosomes of basal corneal epithelial cells
  • Abnormal basement membrane of basal corneal epithelium?
  • Hyaline membrane forms on ulcer
  • defect in anterior stroma?
59
Q

Tx for indolen ulcers

A
  • Remove abnormal epithel
    • topical anesthetic
    • debride with q-tip
    • may have to repeat several times
    • rub cornea with dry q-tips
  • superficial ulcers only
  • Medical tx
    • just like simple superficial ulcer
    • may add hyperosmotic agents
      • 5% NaCl ointment or soln
  • Bandage soft contact lense
    • supports stroma in healing
  • Grid Keratotomy
    • rule out infection
    • diamond bur
    • don’t perform on cats or horses
60
Q

Corneal sequestration in cats

A
  • AKA
    • corneal black spot
    • corneal nigrum
  • breeds most commonly affected
    • brachycephalics:
      • troubles distributing tear films
      • corneal axial denervation compared to other breeds
  • Surgical excision recommended
61
Q

Keratitis

A
  • Non-specific inflammation of the cornea
    • vascularization, edema
    • pigment, infiltrate
  • Variety of etiologies
    • healing corneal ulcer
    • chronic irritation
      • KCS
      • Trichiasis
      • Exposure
    • Immune mediated
62
Q

Pannus

A
  • AKA Chronic superficial keratitis
  • Immune-mediated keratitits
  • Predisposed breeds
    • German shepherds
    • greyhounds
  • exacerbated by UV radiation
  • Temporal corneosclera initially
    • migrates medially
  • Corneal vascularization
  • Pigmentation follows vessels
63
Q

Pannus tx

A
  • no cure
  • medical management
    • topical steroids
    • topical cyclosporine
  • keratectomy
  • beta irradiation
64
Q

Herpetic Stromal Keratitis

A
  • Features
    • Non-ulcerative
    • Chronic
    • Fibrosis, edema, blood vessels
    • immune mediated/immunopathologic
  • med management
    • steroids
    • CsA
    • Antivirals
65
Q

Eosinophilic Keratitis

A
  • Characteristics
    • Proliferative keratitis
    • Non-healing ulcers
    • Fleshy plaques
  • Cytology
    • Eosinophilia
    • Mast cells
    • plasma cells
    • lymphs
  • Med management
    • steroids
    • CsA
66
Q

Corneal Dystrophies

Dogs

A
  • bilaterial
  • inherited/breed related
  • no corneal inflammation, no pain
  • deposition of cholesterol and tryglycerides in stroma
  • serum cholesterol and tryglycerides not usually elevated
  • hypoT4
67
Q

Endothelium

Response to injury

A
  • minimal to no mitosis
    • limited capacity for regeneration
  • When cells lost, remaining cells enlarge and migrate
68
Q

Corneal Endothelial disease

A
  • Hallmark: dense corneal edema
  • Focal or diffuse
  • Inflammation
    • trauma
    • immune-mediated
    • hepatitis: ‘blue eye’
  • Degeneration
69
Q

Corneal Endothelial dystrophies

A
  • anomalous to Fuch’s Dystrophy
  • predispositions
    • Boston Terrier
    • Chihuahua
    • Dachshund
  • Starts as temporal corneal edema
    • extends axially
    • become progressively more dense and opaque
  • Decreased nubers and metaplasia of endothelium

*animal predisposed to ulcers

70
Q

Corneal dz vs glaucoma

A

Measure IOP

71
Q

Endothelial dz

TX

A
  • topical hyperosmotics
    • (5% NaCl)
  • thin permanent conj grafts
  • thermal keratotomy
  • penetrating keratoplasty with corneal transplant
72
Q

Train your client:

Painful eyes are….

A

Same day emergencies

Ophtho (sophomore) (11 decks)

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