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Opthamology > Corneal Disorders > Flashcards

Corneal Disorders Flashcards

1
Q

Layers of the Cornea

A 
from innermost to outermost 
-epithelial cells
-Bowmans layer
-stroma (highly innervated & 90% of cornea)
-Descemets Membrane
-Endothelial cells 
(anterior chamber)
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2
Q

Red flags of Corneal Disorders

A
  • reduction of visual acuity
  • sever deep eye pain (not just irritation)
  • ciliary flush (redness most pronounced at the limbus)
  • photophobia
  • severe foregin body sensation that prevents pt from keeping the eye open
  • corneal opacity (looks cloudy–we are worried about infection)
  • Fixed pupil
  • severe HA w/ nausea
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3
Q

Subconjunctival Hemorrhage

  • Sx
  • dx confirmed by
  • potential cause?
  • tx
A

-Sx: asymptomatic, typically dont notice until they see in mirror.

  • this is blood that has extravasated (popped blood vessel in sclera) NOT injection
  • may occur spontaneously w/ cough, sneeze, strain, or vomiting.

-dx confirmed by: normal visual acuity, absence of discharge, photophobia, foreign body sensation.
Possibly HTN related???

tx: no specific therapy
blood typically reabsorbs 1-2 wks

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4
Q

What is injection of Conjunctiva?

A

-tiny blood vessel appearance, eye appears red and irritated, could mean viral, bacterial conjunctivitis

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5
Q

What is Keratoconus?

A

-degenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape than its normal gradual curve.

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6
Q

Presentation of Keratoconus

A
  • substantial distortion of vision
  • photophobia
  • dx in adolescent years typically
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7
Q

Tx of Keratoconus

A

-corrective lenses fitted by specialist are effective enough to allow pt to continue to drive legally and function normally.

Surgery: intrastromal corneal ring segments, mini asymmetric radial keratotomy, corneal transplant.

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8
Q

What is a Corneal Abrasion ?

A

any defect in the corneal surface epithelium

aka corneal epithelial defect

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9
Q

Classifications of Corneal Abrasions

A
  • traumatic; mechanical trauma (fingernail, paper, make up applicator, branch)
  • foreign body (wood, glass, plastic)
  • contact lens; removal of or over warn, improperly fitted or improperly cleaned lens.
  • spontaneous/recurrent erosions; no injury or foreign body; May be autoimmune disease related.
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10
Q

Clinical Presentation of Corneal Abrasion

A
  • a lot of eye pain ( cornea is richly innervatead w/ sensory pain fibers)
  • inability to open eye d/t foreign body sensation
  • photophobia
  • pt too uncomfortable to work, drive, or read.

*** any pt who complains of eye pain with foreign body sensation preventing opening of the eye generally can be presumed to have a corneal epithelial defect.

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11
Q

What you will see on eye examination of someone with a corneal abrasion

A
  • pupil is typically small from reactive miosis (constriction)
  • large nonreactive or irregular pupil suggest injury to pupillary sphincter
  • hyphema (blood) or hypopyon (pus) in anterior chamber…means infectionCALL OPHTHO!!!
  • visual acuity may be normal if abrasion is away from visual axis, abnormal if abrasion is in visual axis
  • injection will be apparent
  • no discharge, only tears
  • no corneal opacity, if there is concerned about ulcer or infection

*any hint that it may be penetrating trauma you should discontinue the exam, shield the eye and call the ophthalmologist.

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12
Q

When should fluoroscein staining be used?

A

should be done after penlight and funuscopic exam if:

  • corneal abrasion suspect and…
  • lack of signs of other disorders
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13
Q

Keys when using fluourscein

A
  • make sure fluoroscein strip doesnt touch any area of the eye
  • use magnifying glass on a head lamp or the woods lamp
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14
Q

Important principles to remember when thinking about tx of corneal abrasion

A
  • once the epithelium has been disrutped it is now prone to secondary infection
  • the eye is the most vascular part of the body
  • most corneal abrasions heal regardless of therapy in 24-72 hrs.
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15
Q

Tx of Corneal Abrasion

A
  • dont patch unless ophtho tells you to
  • topical abx; ointment is better than drops because it functions as a lubricant.
  • if no contacts you prescribe erythromycin and sulfacetamide.
  • *aminoglycosides should be avoided since they can be toxic to the epithelium.
  • *Steroids are CI, they slow epithelial healing and reduce host resistance to superinfection.

For traumatic/ foreign body abrasion:
-Pain control: cycloplegic agents (inhibit pupil constricting to light which helps with pain, does not relieve foreign body sensation)

-systemic therapy: opiods can be used for comfort

**Topical anesthetics are never to be prescribe for pain relief as they delay corneal epithelial healing

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16
Q

Tx of corneal abrasion for contact lens wearers

A
  • throw out contacts and do not wear them again until completely healed
  • topical abx that is effective against pseudomonas
  • ofloxacin or ciprofloxacin
  • ** do not use erythromycin or sulfacetamide
  • cyclopegic agents
  • opiods as necessary
  • d/t severe risk of infection these pts should NEVER be patched.
17
Q

Contact lens wear is the most common cause of what infection?

A
  • infectious keratitis–pseudomonas

* can result in corneal melting and perforation within 24hrs

18
Q

Steps of foreign body removal

A
  1. irrigation
  2. swab
  3. refer…NO PATCH. treat w/ abx ointment.
19
Q

Corneal Ulcers

-due to what?

A
  • d/t infection:
    bacteria, fungus, virus, ameba
-non-infectious causes 
neurotrophic keratitis 
exposure keratitis
severe dry eyes
severe allergic eye disease

*if not infectious its generally a systemic cause.

20
Q

Bacterial Keratitis

  • most common pathogens
  • who is more apt to get this?
  • what does cornea look like>
  • how treat?
A
  • pseudomonas aeruginosa
    pneuomococcus
    moraxella
    staphylococcus
  • contact lens wearers, especially overnight or trauma
  • cornea is hazy w/ central ulcer and stromal abcess, hypopyon is often present
  • treated with round-the-clock high-concentratino topical abx (fluoroquinolonse are preferred)
21
Q

Herpes Simplex Keratitis

  • where does virus colonize?
  • what type of ulcer is most characteristic?
  • tx
A
  • colonize in the trigeminal ganglion
  • dendritic, branching ulcer
  • debridment and patching +/- topical antivirals…refer to ophtho.
22
Q

Stromal Herpes Simplex Keratitis Signs and Tx

A

-produces increasingly severe conreal opacity with eah re-occurrence

-treat with topical anti-viral, oral anti-viral, topical steroids.
REFER!!

23
Q

Fungal Keratitis

  • when does this occur?
  • more common in what population?
  • progression of disease?
  • tx
A
  • tends to occur after injury from plant material (tree branch in the eye or agricultural setting)
  • most common in contact wearing population
  • indolent, much slower growing infection leading to less acute symptoms.
  • need stromal scrapings for culture and tx is usually difficult and conreal grafting may be required.
24
Q

Acanthamoeba Keratitis

  • what is this?
  • more common in which population?
  • characteristic signs of this?
  • sx
  • tx
A
  • free living ameba
  • contact lens wearers
  • perineural and ring infiltrates in the corneal stroma
  • sever pain, entire cornea will look hazy, looks like aliens.
  • difficult b/c organisms ability to encyst, corneal grafting may be required.
25
Q

Herpes Zoster Opthalmicus

  • what is this?
  • affects which nerve?
  • Signs and Symptoms
  • Tx
A
  • shingles in the eye
  • ophthalmic division of trigeminal nerve
  • malaise, fever, HA, periorbital burning and itching, rash (vesicular–> pustular—> crusted), Ocular signs include conjuncitivits, episcleritis, anterior uveitis(middle layer of the eye), and increased intraocular pressure

****involvment of the tip of the nose predicts eye involvment.

Tx: oral vancyclovir within 72 hours of rash, anterior uveitis requires topical steroids and cycloplegia
REFER!!!!

26
Q

Eye pain + foreign body sensation = ???

A

corneal abrasion

27
Q

Subconjunctival hemorrhages are ____.

A

benign

28
Q

What is the true aim in treating conreal abrasion?

A

prevention of infection, especially pseudomonas in contact lens pt.

Opthamology (8 decks)

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