noninfectious corneal disorders

corneal epithelium characteristics

6-8 cell layers attached to basement membrane

regenerates in 7-10 days

stems cell located at limbus; migrate to central cornea

epithelial wound healing stage 1

latent inflammatory phase (4-8 hrs)

mitosis stops at wound edge & damaged cells shed

MMP-9 up regulation breaks cell adhesion (hemis)

cells develop filopodia (foot) for migration

epithelial wound healing stage 2

cell migration (12-24 hrs)

inflammatory responses continues

cells migrate in a monolayer to close the wound to form X or Y suture

cells start reestablishing hemis

epithelial wound healing stage 3

adhesion & proliferation (24-36 hrs)

cells continue forming adhesion complexes to bowman's layer

cell proliferation reestablishes normal epithelial thickness & nerve regenerate

damaged basement membrane may slow this process

causes of punctate epithelial erosions (PEE)

dry eye

blepharitis

CL wear

lagophthalmos

what are PEEs?

intracellular gaps due to tight junction loss

damaged or dead epithelial cells

PEEs stain with what dyes

NaFl

Rose Bengal

PEE treatment

frequent lubrication with artificial tear

nighttime ointment

if pt is a CL wearer, discontinue CL use until heals

consider prophylactic antibiotic in CL wearers

thygeson SPK onset

young adult (mid 20s)

chronic with periods of exacerbation & remission

symptoms of thygeson SPK

irritation

mild photophobia

vision blur

tearing burning

bilateral coarse, elevated grey lesions

no conjunctival hyperemia

what is the suspected cause of thygeson SPK?

viral etiologies

treatment for thygeson SPK

lubrication

topical steroid: loteprednol (lotemax) QID x 4 weeks then taper for 2-3 months

restasis BID (long term)

bandage soft CL

what is a bandage CL?

provides a protective layer over the cornea to decrease continuous rubbing from the eyelid & to promote healing

if there is an epithelial defect what should you add to the bandage CL?

prophylactic antibiotic

FDA approved therapeutic bandage CLs?

acuvue oasis (6 nights)

air optix night & day aqua (30 day)

purevision (30 day)

patiophysiology of filamentary keratitis/keratopathy

loose area of epithelium attracts deposits of mucus & cellular debris from dead epithelial cells that are shed into the tear film

symptoms of filamentary keratitis

foreign body sensation

discomfort

redness

photophobia

signs of filamentary keratitis

strands of degenerated epithelial cells & mucus move with blinking

strands are attached to cornea at one end

filaments stain with rose bengal & NaFL

causes of filamentary keratitis

severe dry eye (ADDE)

CL over wear

post surgical

prolonged eye closure/patching

chronic ocular surface toxicity

superior limbic keratoconjunctivitis

neurotrophic keratopathy

treatment for filamentary keratitis

lubrication

debridement

bandage CL

10% N-acetylcysteine TID-QID

topical steroid

muro 128 solution QID or ointment qhs

punctal occlusion

amniotic membrane

what is 10% acetylcysteine (mucomyst)?

used as an oral inhalant for pts with bronchial diseases (asthma, cystic fibrosis)

must be made into topical drop by compounding pharmacy

what is an amniotic membrane?

made from amniotic membranes of donated placentas

tissues can be placed on polycarbonate ring for insertion

what does an amniotic membrane do?

reduces inflammation & promotes regenerative healing by boosting stem cell proliferation on ocular surface

remains on eye for 1 week

pathophysiology of recurrent corneal epithelial erosion

abnormally weak attachment between the basal cells of the epithelium & their basement membrane

etiology of recurrent corneal epithelial erosion

prior minor corneal trauma

epithelial basement membrane dystrophy

meesmann dystrophy

reis bucklers dystrophy

symptoms of corneal epithelial erosion

severe pain, photophobia, redness, blepharospasm, tearing

occurs after waking up

epithelial defect that stains with NaFl

absence of stroma infiltrates

treatment for recurrent epithelial erosion

prophylactic topical antibiotic: erythromycin QID

lubrication

bandage CL

topical cycloplegia (for pain)

sodium chloride (muro 128) QID (after reepithelialization)

doxycycline (50 mg BID 4-6 weeks)

topical steroid

surgical

what topical cycloplegia can you use for recurrent epithelial erosion

cyclopentolate 1%

homatropine 5%

what surgical procedure can you do for recurrent epithelial erosion

anterior stromal puncture

photo therapeutic keratectomy

superficial keratectomy with diamond burr polishing

what should you NOT do that will slow down epithelial healing of recurrent epithelial erosion?

patching the eye

what is anterior stromal puncture

improves corneal epithelial adhesion by producing scar tissue between the epithelium & anterior stroma

used for RCE that are AWAY from visual axis

what is phototherapeutic keratectomy (PTK)

minor surgical procedure that uses an excimer laser

removes abnormal areas of thickened basement membrane to provide more solid & even base for epithelial adhesion & healing

what is superificial keratectomy with diamond burr polishing

epithelium is removed down to bowman's layer & up to 1.5 mm from the limbus

diamond burr is used to polish bowman's layer

bandage CL is placed on eye

cause of exposure keratopathy

incomplete eyelid closure:

- facial nerve palsy

- lid scarring

- proptosis

- eczematous skin tightening

- sedated pts

symptoms of exposure keratopathy

foreign body sensation

pain, photophobia

mild PEE in inferior cornea

worsening: epithelial breakdown, stromal melting, corneal proliferation

exposure keratopathy treatment

aggressive lubrication

nighttime ointment

eyelid taping

bandage soft contact lens

amniotic membrane

tarsorrhaphy

treat underlying condition

pathophysiology of neurotrophic keratopathy/keratitis

loss of sensory innervation to the cornea resulting in:

- decreased tear reflex

- intracellular edema

- loss of goblet cells

- persistent ulceration

- increased apoptosis & reduced proliferation of epithelial cells

causes of neurotrophic keratopathy/keratitis

recurrent HSV/HZV infections of cornea

trigeminal ganglion ablation for treatment for trigeminal neuralgia

peripheral neuropathy due to DM

stroke

tumor

stages of neurotrophic keratopathy/keratitis

stage 1: interpalpebral epithelial irregularity, staining & edema

stage 2: persistent epithelial defect

stage 3: stromal melting/scarring

treatment of neurotrophic keratopathy/keratitis

aggressive lubrication

oral tetracyclines

eyelid taping at night

tarsorrhaphy

botox induced ptosis

bandage CL

amniotic membrane

oxervate

what is oxervate?

recombinant human nerve growth factor

1 gtt 6x/day x 8 weeks

what is dellen?

localized area of corneal stromal dehydration & thinning with intact epithelium (area won't stain with NaFl; it will pool)

what is the cause of a dellen?

persistent drying of focal area due to adjacent elevated lesion

treatment of dellen?

manage underlying cause

aggressive lubrication

bandage CL

pathophysiology of sub epithelial infiltrates

penetration of wbc into the anterior stroma due to an inflammatory response to toxins, hypoxia, infection, corneal surgery

where are inflammatory cells recruited from in SEIs?

limbal vasculature

will chronic or active SEIs stain with NaFL?

active

how to treat SEI if cause is bacterial toxin

antibiotic/steroid combo

how to treat SEI if cause is medication toxicity

discontinue offending agent

initiate topical steroid

how to treat SEI if cause is chlamydia infection

oral antibiotic

how to treat SEI if cause is adenoviral infection

topical steroid

how to treat SEI if cause is hypoxia due to CL overwear?

discontinue CL wear

antibiotic steroid combo

what are metabolic keratopathies

corneal deposits caused by inherited metabolic disorders of protein & amino acid metabolism or inherited lysosomal storage disorders

types of metabolic keratopathies

cystinosis

Wilsons disease

fabrys disease

what is cystinosis?

widespread deposit of cystine crystals throughout the body including cornea (all layers), conjunctiva & retina

characteristics of crystals in cystinosis

seen in 1st year of life or adolescence

can lead to epithelial erosions & photophobia

no effect on VA

what is Wilsons disease

decreased biliary copper excretion leading to copper deposition throughout the body (liver, brain, kidneys, cornea)

systemic signs of Wilsons disease

chronic liver disease & hepatic failure

acute renal failure

neuropsychiatric disorders: tremors, behavioral changes

ocular signs of Wilsons disease

Kayser fleischer ring: copper deposition in peripheral descemet membrane

what is fabrys disease

x-linked deficiency of alpha-galactosidase A enzyme & leads to abnormal tissue accumulation of a glycolipid

systemic features of fabrys disease

- cardiomyopathy, HTN, stroke

- renal disease

- tinnitus

ocular manifestations of fabrys disease

- whorl keratopathy (cornea verticillate): white to golden brown corneal stromal deposits in vortex pattern

- conjunctival vascular tortuosity

what medications cause whorl keratopathy?

amiodarone (anti-arryhythmic)

chloroquine (immunosuppressive)

what light are iron deposits on the cornea best seen with?

cobalt blue light

what is Hudson stahli line

iron deposition line in the basal epithelium where the tear film becomes stagnant usually on inferior 1/3 of cornea

what is stocker's line

iron deposits in basal epithelium at leading edge of a pterygium

what is fleisher's ring

iron deposits in basal epithelium in patients with keratoconus