L13 Corneal Injury

while assessing corneal injury what aspect of intro exams is most important

hx, get a complete description of the traumatic event

what characteristics of object trauma is important (2)

foreign body (inert vs inflammatory)

energy (amount, type, wavelength, power, and duration)

what is corneal abrasion

removal of corneal epithelium

corneal abrasion is also a ____ defect without underling corneal _____ or infection

epithelium, inflammation

t/f corneal abrasion is one of the most common defects

true

how causes corneal abrasion

tangential impact from foreign body

t/f corneal abrasions can be from finger nails, paper, mascara brushes, plants and CL use

true

tangential force applied--> epithelial cells separate from underlying attachement

this is the pathophysiology for

corneal abraison

t/f corneal abrasions doesn't always include Bowmans membrane

true

while examining corneal abrasion you should look for (3)

extent, location, and globe penetration

a patient comes you complaining of pain and foreign body sensation. upon silt lamp and prelims they present tearing, photophobia with a VA worse than 20/20. as well as loose epithelium, staining defect, roughening of corneal reflex, AC reactions and granular stroma. What is your diagnoisis

corneal abrasion

what corneal abrasion you just diagnosed, what are 3 treatment options

1. cycloplegia possibly with NSAID for symptoms

2. topical antibiotics for prophylactic reasons

3. protective healing

one of tx options is cycloplegia; what are the 3 options available with dosing

1. cyclopentolate 0.5% or 1% 1gtt BID or TID for small to moderate abrasions

2. homatropine 5% or scopolamine 0.25% for larger abrasions

3. ketorolac 0.4-0.5% QID x3 days

one of tx options is topical antibiotics; what are the two options

1. broad spectrum abx: polytrim 1gtt OR fluoroquine 1gtt QID or tobramycin/gentamicin

2. aminoglycosides

for protecting healing, you should avoid patch if CL related? yes or no. why

yes; risk of MK

for protecting epithelium healing for corneal abrasions. what is the process

epithelial debridement may be a patch of BCL

1 day f/u if patching or BCL and corneal abrasion is large or central

AND

2-5 days f/u if small or peripheral

is management for

non CL wearer

Close f/u with additional 1-2 days of abx prophylaxis following closure then resume CL wear after 1 week cessatin of abx

this is the management for

CL wearer

what can occur after a corneal abrasion

Recurrent corneal erosion

what is an recurrent corneal erosion (RCE)

repeated breakdown of epithelium due to dysfunction in epithelial-stromal complex integrity

what are some risk factors / etiology for RCE (4)

history of corneal injury/ truama

dystrophies

ocular surace disease

systemic illnesses

where does RCE typically occur

within lower half of cornea

the 4 different Pathophysiology for _____ is

1. abnormalities in normal adhesion of epithelium leads to epithelial elevation and accumulation of debris disrupts attachment of epithelium

2. random production of BM and CT material leads to disrupted attachment of epithelium

3. increased epithelial separation at night + eyelid adherence leads to shearing forces to epithelium

4. MMP degrade collagen and laminin leading to upregulation of MMPs leads to BM degradation and poor BM adhesion

RCE

a patient comes to you complaining about pain. they explain the pain is more severe when just waking up. The pain is random and not constant. they elaborate they sometime feel like they cant see, their eyelids get swollen , teary, and light is bothersome. with redness. during slit lamp examine you notice the epithelium is loose and some epithelial microcysts. with staining, there is some stain as well as areas with negative staining. what is your diagnosis

RCE

a sign of RCE is there are areas of negative staining, which is significant. why?

there are divots/ folds that will stain and then areas that will not because it is elevated

when considering RCE as a diagnosis what are some important clinical hx to ask (5)

1. previous trauma

2. prior episodes

3. pain on waking

4. epithelial defect or loose epithelium

5. predisposing conditions

RCE can lead to (3)

bacterial keratitis, fibrosis, decreased vision

what is the tx for acute RCE (3-4)

cyclopentolate 1% tid

AND

erythromycin or bacitracin QID -6xday (topical 1gtt QID if large or BCL)

POSSIBLY: 5% NaCl for proplyctic reasons

what is the tx for resolved RCE (2)

artificial tears/ointment

5% NaCl qhs x 3-6 months

what are the pro and cons of topical ointment

pro: longer contact time

cons: cant see when its on but can use the other eye

RCE can be recalcitrant or not respond to tx, what are the tx options then?

1. 5% NaCl prophylactically

2. oral doxy 50 mg +/- topical steroid (fluorometholone 0.1% BID- QID for 2-4wks)

3. extended BCL

4. anterior stroma puncture (manual or laser)

5. debridement + diamond burr polish

6. phototherapeutic keratectomy (PTK)

___ ___ ___ is corneal damage following exposure to UV radiatin

ultraviolet keratopathy (photokeratitis)

what is the wavelength for UVA

320-400nm

what is the wavelength for UVB

290-320nm

what is the wavelength for UVC

200-290nm

the cornea absorbs what UV wavelengths

UVB and UVC

what can 3 things that can lead to ultraviolet keratopathy (photokeratitis)

welders keratitis, snow blindness, UV lamps

a patient comes to you telling you they feel like there is something stuck in their eye, pain and overall discomfort. they also cant stand looking at light. you ask for history and they said they are daily welders. during slit lamp there is slight edema, dull corneal reflex, less corneal sensitivity, and some epithelial defects. what is your diagnosis

photokeratitis- UV radiation

when someone is diagnosed with photokeratitis- UV radiation. what is their prognosis

usually full recovery

what can occur after photokeratitis- UV radiation (2)

pterygium, endothelial morphology changes

what are other differentials to think about when diagnosing photokeratitis- UV radiation (4)

dry eye, drug toxicity, chemical exposure, viral conjunctivitis

what are 3 tx options for photokeratitis- UV radiation with dosing

cycloplentolate 1% gtt TID

erythromycin or bacitracin 4-8x daily

oral analgesics prn

___ ___ ___ ___ is corneal damage due to wavelengths above the visble spectrum (10^-4). usually accompanied by intense heat

infrared radiation corneal injury

what are two types of infrared radiation corneal injury

flame and contact

although possible to get a infrared radiation corneal injury, its rare because of our ___ reflex and ___ turn

blink, head

clinical presentation of infrared radiation corneal injury consists of destruction of the ______, stromal _____ which is worse than the epithelial damage. the changed within 20 minutes with continued ____ and stromal edema

epithelium, opacification, progression

_____ ___/____ is corneal injury secondary to direct application of heat.

thermal burn/ keratopathy

for thermal burn/ keratopathy, tissue reaction is dependent on

temperature of heat source

for thermal burn/ keratopathy with HOT WITH HIGH HEAT leads to (4 in chronicological order)

-->severe burn getting deeper layers--> opacification--> sloughing-->corneal thinning

for thermal burn/ keratopathy with LOW HEAT leads to (2 in chronicological order)

--> tear films cools cornea--> cast of anterior surface of eye

what are prognastic factors for thermal burn/ keratopathy (4)

temperature, heat-retaining capacity of material, duration, area

a patient comes to you with signs of thermal burns. you consider it to be severe. what are the tx for this

surgical intervention for corneal ectasia or symblepharon

a patient comes to you with signs of thermal burns. you consider it to be minor. what are the tx for this (3)

similar to corneal:

alleviate sx, prophylactic antibiotics, protective healing

what can occur after a thermal burn/ keratopathy (4)

angiogenesis, corneal flattening, scarring/opacification, corneal necrosis

___ ___ is a chemical, nonmechanical injury to the eye that damages the ocular surface.

chemical burn

can a chemical burn cause permanent vision loss? yes or no

yes

can chemical burns causes acute and chronic changes?

yes

chemical burns often happen in who?

young, working individuals,

lower to middle income

(dr e said basically anyone)

what is the pathophysiology for alkali and and acid burn?

stromal penetration--> shrinkage of collagen--> distortion of TM release of PG--> acutely elevated IOP

____ of chemical burn depends on

type of chemical

concentration & pH of solution

extent of exposure

duration of exposure

degree of penetration

severity

there are many sequelae to chemical burns in the conj/ limbus or cornea, but what are the important 6?

limbal stem cell defiency

persistent epithelial defects

recurrent corneal erosions

dry eye

uveitis

glaucoma

____ chemical burn is damage secondary to alkalis. its more frequent

alkali

alkali chemical burn is more severe than other type of burns? yes or no

yes

during alkali burns, _____ intraocular damage noted at pH greater than or equal to ___

irreversible, 11.5

pathophysiology of alkali burn: begins with a hydroxyl ion ______ fatty acids in cell membranes leading to cell ___ and then to hydrolysis and _____ of proteoglycans & collagen

saponifies, lysis, denaturation

greater penetration of alkali burns lead to

greater damage to stroma & endothelium + intraocular structures

what causes alkali burns (6)

ammonia

lye

calcium hydroxide (lime)

potassium hydroxide

airbag powder

how does alkali chemical burns present?(2)

ischemic necrosis and blanches conjunctival vessels

alkali chemical burn- superior is worse than inferior bc there is no blood supply leading to necrosis of the cells (irreversible)

____ chemical burn is

corneal injury secondary to exposure to acids

acid

acid chemical burn is generally ____ severe

less

t/f in acid burns, superficial damage due to immediate precipitation of epithelial proteins unless strong or high concentration acid

true

pathophysiology of acid burn begins with hydrogen ion of acidic alters __ and then anion leading to protein ____ and ____ in corneal epithelium and superficial stroma allowing penetration of the barrier

pH, binding and precipitation,

what causes acid burns (10)

sulfuric, sulfurous, hydrochloric, nitric, acetic, formic, hydrofluoric

battery acid, pool cleaner, vinegar

a patient comes to you office complaining of severe pain and they mentioned they were squeezing lime and decent amount got into their eye. whats their diagnosis?

alkali chemical burn

a patient comes to you office complaining of severe pain and they mentioned they were charging their tesla and the battery exploded and got into their eye. whats their diagnosis?

acid chemical burn

a patient comes to your office with a chemical burn. you decide its a grade I or acute. whats the treatment (3)

1. irrigate with 1L for 15 mins until neutral pH. get into fornices

2. debride of necrotic tissue

3. topical steroid & oral pain med

care with ciproflaxin bc its a vasoconstrictor

while irrigating what is something important NOT to do

do NOT irrigate with opposite neurilizing agent

while treating acutely or Grade I chemical burn. what is added if IOP is elevated? (4)

acetozolamide 250mg PO qid or 500 mg PO BID

OR

methazolamide 25 to 50mg po bid or tid

add b-blocker (timolol 0.5% bid)

NO a-agonist

what is tx options for Grade II-III chemical burn (7)

10% topical ascorbate or citrate for alkali q2h

BCL

doxy 100mg po bid

oral vitamin C

amniotic membrane (inoffice)

autologous serum tears

platelet rich plasma

what is the tx options for a Grade IV chemical burn including if melting/perforating (5)

tarsorrhaphy

melting: collagenase inhibitors,

cyanoacrylate tissue adhesive,

patch graft,

corneal translate

tx for _____ chemical burn includes

reconstruction of eyelids & fornix

- conj graft or tasorrhaphy

amniotic membrane transplant

LSC transplant

keratoprosthesis

glaucoma management

chronic