Corneal Disorders Flashcards Preview

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Flashcards in Corneal Disorders Deck (28):
1

Layers of the Cornea

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

2

Red flags of Corneal Disorders

-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

3

Subconjunctival Hemorrhage
-Sx
-dx confirmed by
-potential cause?
-tx

-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

4

What is injection of Conjunctiva?

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

5

What is Keratoconus?

-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.

6

Presentation of Keratoconus

-substantial distortion of vision
-photophobia
-dx in adolescent years typically

7

Tx of Keratoconus

-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.

8

What is a Corneal Abrasion ?

any defect in the corneal surface epithelium

aka corneal epithelial defect

9

Classifications of Corneal Abrasions

-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.


10

Clinical Presentation of Corneal Abrasion

-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.

11

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

-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.

12

When should fluoroscein staining be used?

should be done after penlight and funuscopic exam if:
-corneal abrasion suspect and...
-lack of signs of other disorders

13

Keys when using fluourscein

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

14

Important principles to remember when thinking about tx of corneal abrasion

-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.

15

Tx of Corneal Abrasion

-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

16

Tx of corneal abrasion for contact lens wearers

-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

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

-infectious keratitis--pseudomonas
*can result in corneal melting and perforation within 24hrs

18

Steps of foreign body removal

1. irrigation
2. swab
3. refer...NO PATCH. treat w/ abx ointment.

19

Corneal Ulcers
-due to what?

- 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

Bacterial Keratitis
-most common pathogens
-who is more apt to get this?
-what does cornea look like>
-how treat?

- 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

Herpes Simplex Keratitis
-where does virus colonize?
-what type of ulcer is most characteristic?
-tx

-colonize in the trigeminal ganglion

-dendritic, branching ulcer

-debridment and patching +/- topical antivirals...refer to ophtho.

22

Stromal Herpes Simplex Keratitis Signs and Tx

-produces increasingly severe conreal opacity with eah re-occurrence

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

23

Fungal Keratitis
-when does this occur?
-more common in what population?
-progression of disease?
-tx

-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

Acanthamoeba Keratitis
-what is this?
-more common in which population?
-characteristic signs of this?
-sx
-tx

-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

Herpes Zoster Opthalmicus
- what is this?
-affects which nerve?
-Signs and Symptoms
-Tx

-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

Eye pain + foreign body sensation = ???

corneal abrasion

27

Subconjunctival hemorrhages are ____.

benign

28

What is the true aim in treating conreal abrasion?

prevention of infection, especially pseudomonas in contact lens pt.