AED - Superficial Corneal Diseases - Week 9 Flashcards
How thick is the cornea centrally? Give a range.
490-560 microns
How many cells thick is the corneal epithelium? What does this prevent the diffusion of?
6-8 cells thick
Prevents diffusion of fluorescein
What layer of the cornea is significant in recurrent corneal erosion?
Basement membrane
Consider trauma to Bowman’s layer of the cornea. Does it regenerate?
No regeneration following trauma
What happens to Descemet’s membrane during oedema?
Folds occur
Do endothelial cell numbers remain constant as we age? Can they regenerate if they are lost?
Cell numbers decrease with age and do not regenerate
How does drop toxicity appear with staining?
Small spots of fluorescein distributed evenly across the cornea
What constitutes filamentary keratopathy (2) and what is it usually due to (2)?
Usually due to abnormal areas of corneal epithelium and excess mucus in tears
Requires corneal irregularity in conjunction with tear film abnormality
In filamentary keratopathy, what adheres strongly to the corneal surface?
Filaments - mucous strands attached to abnormal epithelial cell plaques
Is filamentary keratopathy common? List 5 common causes of this condition.
Uncommon
Severe dry eye
Superior limbic keratoconjunctivitis
Ocular surgery (cataract/corneal graft)
Recurrent corneal erosion
Neurotrophic keratopathy
List 4 symptoms of filamentary keratopathy. Explain why they occur if applicable (3).
Foreign body sensation
-pulling on filaments with blink
watery eye
-due to stimulated reflex tears
Decreased VA
-due to filaments and poor tear flims
Photophobia
What appearance do filaments in filamentary keratopathy have? What colour and how long? What do they stain well with? What about fluorescein? Which end of the filament is adherent and to what?
Greyish filaments, one to several mm in length
Stains well with rose bengal and lissamine green
Less well with fluorescein
Adherent to corneal plaque at the proximal end of the strand.
List three components to assessing filamentary keratopathy.
Good history
Appropriate slit lamp and tear assessment
How are filaments in filamentary keratopathy treated? Are they recurrent?
What does removal of the filament cause and can it be treated?
They are removed under local anaesthesia using sterile forceps
Will reccur if the underlying cause isnt treated
Removal will cause an epithelial defect - topical antibiotic prophylaxis
Aside from treating the filament itself, list 4 treatment options for filamentary keratopathy.
Ocular lubricants
Topical corticosteroids if filaments are persistent
Bandage contact lens
Topical acetylcysteine
How common is superficial punctate keratopathy? What acronym is used for it? What is it due to?
Very common
Also called PEE
Due to superficial damage (erosion) of the surface corneal epithelium
List 8 common causes of superficial punctate keratopathy.
Dry eye
Drug toxicity
Foreign body
Contact lenses
Hyopxia
Lid disease
Corneal disease
Thygeson’s superficial punctate keratopathy
What three dyes does superficial punctate keratopathy stain with?
Fluorescein
Rose bengal
Lissamine green
What does the position of staining/erosion in superficial punctate keratopathy indicate?
It may determine cause
List symptoms of superficial punctate keratopathy (3).
May be asymptomatic
If symptomatic - gritty and photophobia
What may happen if superficial punctate keratopathy is dense?
Visiond loss
List 5 signs of superficial punctate keratopathy.
Fine, coarse, dense, or sparse areas of superficial corneal epithelial erosions
Eyes remain white and clear
List 6 components for assessing superficial punctate keratopathy.
History
Slit lamp
Fluorescein
Wratten filter
Tear workup
Identify underlying cause
Within what time period will superficial punctate keratopathy typically repair? What can promote repair?
Within 24h
Ocular lubricants can promote repair
If wearing contact lens and superficial punctate keratopathy is noticed, what advice should be given?
Discontinue contact lens wear
Are corneal infiltrates present with superficial punctate keratopathy?
No
What may be required if superficial punctate keratopathy is severe (3)?
Prophylactic topical antibiotic cover
Steroids
-only if underlying condition is inflammatory
Are subepithelial infiltrates common or rare? What are they due to?
Relatively common
due to inflammatory response within the anterior corneal stroma
-leukocyte infiltration
List 5 common causes of subepithelial infiltrates.
Viral infection
Blepharitis
Tygeson’s SPK
Preservative toxicity
Contact lenses
List 5 symptoms of subepithelial infiltrates.
Foreign body sensation
Photophobia
Watery eye
Decreased visiond if central
SPK over the area of infiltrate
How do subepithelial infiltrates appear? What may happen with the overlying epithelium?
Appears as a subepithelial, diffuse grey opacity
Overlying epithelium may stain with fluorescein
List 6 components for assessing subepithelial infiltrates.
History
Slit lamp
Fluorescein
Wratten filter
Tear workup
Identify underlying cause
What is a treatment option if subepithelial infiltrates are symptomatic?
Ocular lubricants
What should be done when treating subepithelial infiltrates?
Manage the underlying cause
What should be considered if there is significant epithelial breakdown over the infiltrate with subepithelial infiltrates?
Antibiotics
Can steroids be given for subepithelial infiltrates?
Yes, with a slow taper
Define CLARE-CIE and what it is.
Contact lens (induced) acute red eye
It is an acute inflammatory event
What can lead to CLARE? What does it lead to (2)?
Contact lens tight fit can lead to a stasis of the tear film, causing a buildup of bacterial population under the lens and limbal hypoxia
What is the hallmark sign of CLARE in a contact lens wearer?
Corneal subepithelial infiltrates
List 5 symptoms of CLARE.
Discomfort
Bulbar conjunctival redness
Irritation
Mild photophobia
Watery eye
Within what time period does CLARE typically resolve? What percentage reccurs and within what time period? Why does this occur (2)?
88% resolves by day 22
Recurrence rate is 30%
Most recurrence within 2 months
Possibly due to not treating inflammation effectively and returning to contact lens wear too early
Why are antibiotics administered concurrently with anti-inflammatories for CLARE management (4)?
Decrease bacterial load
More than normal discharge
Unsure of diagnosis
Optometrist peace of mind
Is CLARE inflammatory or infective, or both?
Inflammatory
How is inflammation in CLARE treated?
Steroids, which must be tapered
Is it ok to use ocular lubricants concurrently with steroids in CLARE?
Yes
What can be done to reduce recurrence of CLARE (3)?
No overnight wear
Change to high Dk
Change to dailies