Non-Infectious Corneal Disorders: Cornea, Anatomy of Rx, Punctate Epithelial Erosions (SPK) & Thygeson SPK Flashcards
how many layers is the epithelium of the cornea?
what is it attached to?
6-8 cell layers,
attached to basement membrane
where are the corneal stem cells located and where do they migrate?
located at limbus → migrate to central cornea.
explain the afferent pathway of blink reflex
long ciliary → nasociliary → V1 → trigeminal ganglion → brainstem
explain the efferent pathway of blink reflex
brainstem → CN7 → orbicularis oculi
explain the afferent pathway of tear reflex
lacrimal → V1 → pterygopalatine ganglion
explain the efferent pathway of tear reflex
greater petrosal → CN7 → lacrimal gland
latent/inflammatory phase (4-8 hrs)
- mitosis stops at wound edge & damaged cells shed
- MMP-9 upregulation breaks cell adhesions (hemidesmosomes)
- cells develop filopodia (“foot” extensions) for migration
what stage of epithelial wounding healing?
stage 1
cell migration (12-24 hrs)
- inflammatory response continues
- cells migrate in a monolayer close to wound to form X/Y suture
- cells start reestablishing hemidesmosomes
what stage of epithelial wounding healing?
stage 2
adhesion & proliferation (24-36 hrs)
- cells continue forming adhesion complexes to Bowman’s layer
- cell proliferation reestablishes normal thickness & nerves regenerate
- a damaged basement membrane may slow this process
what stage of epithelial wounding healing is this?
stage 3
what disorder do these cause?
dry eye, blepharitis, CL wear, lagophthalmos, etc.
punctate epithelial erosions (SPK)
these clinical findings are indicative of?
tiny epithelial defects that stain w/ NaFl & Rose Bengal dye
- intercellular gaps due to tight junction loss
- damaged or dead epithelial cells
punctate epithelial erosions (SPK)
clinical findings of inferior SPK indicative of
lagophthalmos, blepharitis
clinical findings of defuse SPK indicative of
dry eye
these treatments are for what disorder?
frequent lubrication w/ artificial tears; nighttime ointment
if pt wears CLs → discontinue use until epithelium heals
consider prophylactic antibiotics in CL wearers w/ significant SPK
SPK
management: when do you see the pt back for SPK?
depends on severity, pt symptoms, ocular history, etc.
describe anatomy of a prescription
- prescriber’s name required by law (address & phone number required for controlled substances)
- need DEA# to prescribe controlled substances
- pt’s name required by law (address & phone number required for controlled substances)
- date is required
- drug name (generic/brand), strength & type of delivery (topical solution/suspension, topical gel, oral)
- -specify strength if there are multiple strengths
- sig: # of doses, frequency, route
- disp: volume of bottle, quantity of day supply (for oral medications)
- indicate if the pt needs refills & how many
- initial box if you don’t want to substitute for a generic
- sign prescription w/ license number
- -NPI to save time for pharmacists
these signs & symptoms are indicative of?
bilateral, irritation, mild, photophobia, vision blur, tearing, burning
thygeson superficial punctate keratitis
clinical findings:
- coarse, elevated greyish epithelial lesions (usually around pupillary area)
- superficial lesions can stain w/ NaFl
- absent conjunctival hyperemia
- can have mild subepithelial haze
what describes these findings?
thygeson superficial punctate keratitis
what is the management for?
- lubrication, restasis BID (long term),
- therapeutic (bandage) soft CLs
- topical steroid: loteprednol QID x 4 wks → very slow x 3-6 mo
thygeson superficial punctate keratitis
what provides a protective layer over cornea to decrease continuous rubbing from the eyelid & to promote healing?
what if there is an epithelial defect?
bandage CLs
add a prophylactic antibiotic
