Corneal Ectasias Flashcards
which ectasia is a rare, progressive peripheral corneal thinning disorder
pellucid marginal degeneration
when is the onset of pellucid marginal degeneration
2nd-5th decade of life
these signs are indicative of which ectasia:
- bilateral & slowly progressive band of corneal thinning from 4-8 o’clock
- marked steepening just superior to the thinned zone
- intact epithelium & no vascularization
- severe astigmatism & steepening of inferior cornea
pellucid marginal degeneration
when corneal topography shows a “kissing-dove” pattern, what ectasia is this indicative of
pellucid marginal degeneration
how can you manage pellucid marginal degeneration
- RGP CLs
- collagen cross-linking (if progression in steepening)
- surgery (if astigmatism can’t be corrected by other options)
which ectasia is an extremely rare condition that can be congenital or acquired
keratoglobus
if keratoglobus is congenital, what must you differentiate it from
congenital glaucoma
these signs are indicative of which ectasia:
- cornea develops globular ectasia & corneal thinning is generalized
- corneal hydrops are rare
- cornea is prone to rupture from mild trauma
keratoglobus
these clinical findings are indicative of which ectasia:
- irregular retinoscopy reflex
- irregular astigmatism
- globular protrusion of cornea
- diffuse corneal thinning
- normal corneal diameter
keratoglobus
how do you manage keratoglobus
- protective eyewear (polycarbonate)
- avoid contact spots
- RGP CLs
if keratoglobus perforates, how do you manage it
surgery
which ectasia is a progressive disorder that begins during puberty, progresses into 3rd-4th decade of life, then stabilizes
keratoconus
what are the 3 syndromes keratoconus is associated with
down syndrome
Ehlers-Danlos
Marfan
pts with vernal keratoconjunctivitis or an atopic disease that causes persistent eye rubbing can be associated with which ectasia
keratoconus
these signs are indicative of which ectasia:
- Charleaux oil drop reflex
- irregular scissor reflex on ret
- Vogt Striae
- Fleischer ring
- Munson’s sign
- progressive corneal protrusion in a cone configuration w/ apical thinning
- steep keratometry readings
keratoconus
these clinical findings are indicative of which ectasia:
- stromal thinning in central/paracentral cornea
- apical protrusion of cornea
- high irregular astigmatism
keratoconus
assessment of what can lead to an earlier diagnosis of keratoconus
posterior corneal curvature
the keratoconus grading scale is based on what
the highest axis of corneal power on keratometry
a mild keratoconus will have what keratometry reading
< 48D
a moderate keratoconus will have what keratometry reading
48-54D
a severe keratoconus will have what keratometry reading
> 54D
progression of keratoconus has a consistent change in at least two of what characteristics?
- steepening of anterior corneal surface
- steepening of posterior corneal surface
- thinning &/or an increase in rate of corneal thickness change
how can you optimize VA in keratoconus
- spectacles in early stages
- RGP CLs
- scleral CLs
what surgeries can be done to treat keratoconus
- intrastromal corneal ring segment implantation
- corneal crosslinking
- corneal transplant in severe cases
which keratoconus surgery is more common & what does it do
corneal crosslinking → slows disease progression
what is contraindicated in pts w/ keratoconus
refractive surgery (LASIK)
what is the procedure for corneal crosslinking
riboflavin (vitamin B2) is combined with UV-A radiation
what does corneal crosslinking do
strengthens corneal tissue
how do intrastromal corneal ring segments work
- alter morphology of cornea
- alter refractive power of cornea
what is an acute break in Descemet’s membrane
corneal hydrops
which ectasia occurs when fluid leaks into stroma, causing significant corneal swelling & opacification
corneal hydrops
these symptoms are indicative of which ectasia:
- acute decreased VA
- conjunctival hyperemia
- significant pain
- significant photophobia
corneal hydrops
these are all treatments for which ectasia:
- cycloplegia
- Muro 128 (hyperosmotic gel/drop that dehydrates stroma)
- topical NSAID
- bandage soft CLs
corneal hydrops
when ophthalmological intervention is needed for corneal hydrops, what do they do
anterior chamber gas bubble to speed up recovery
