module 1 corneal surface defects and dry eye syndrome

Question 1

corneal surface defect

Answer 1

when the corneal epithelium is interrupted
- trauma from foreign objects
- contact lens wearers: prolonged use of lenses

Question 2

Full-thickness lacerations

Answer 2

can occur with ocular trauma and sometimes appear slimialr to epithelial defects

Question 3

infectious keratitis

Answer 3

corneal ulcer
- epithelial defect with an infiltrate, or white area in the cornea.

Question 4

corneal abrasion

Answer 4

partial or complete defect in the epithelial layer after some traumatic event or UV light exposure
causes:
- chemical or mechanical debridement -> trauma
- chemicals
- ultraviolet radiation

Question 5

corneal erosions

Answer 5

Occur if an abrasion disrupts the Bowman layer, partial or complete with no assoc. to trauma
- dec. evaporations during sleep -> formation of a fluid layer above the non-healed bowman layer and below the epithelium.
- can lead to repeated sloughing of epithelium
- allows bacterial, viral, or fungal organisms to invade -> ulcer

Question 6

Bowman layer

Answer 6

smooth, acellular layer of tissue just beneath the corneal surface

Question 7

corneal abrasion or foreign body s/s

Answer 7

sudden onset severe eye pain
- resolves with topical anesthetic
foreign body sensation
blurred vision
redness
tearing
light sensitivity
eyelid swelling
blepharospasm

Question 8

corneal abrasion or foreign body physical exam

Answer 8

vision may be limited if defect of foreign body falls within the visual axis
eyelids may appear swollen
conjunctiva is injected
cornea may have mild haze
foreign body may be visible

Question 9

linear vertical lines seen with fluorescein dye

Answer 9

typically caused by subtarsal (under eyelid) foreign bodies
- eversion of upper eyelids to check

Question 10

branching or dendritic pattern defect with fluorescein

Answer 10

herpetic cause

Question 11

full-thickness laceration and fluorescein

Answer 11

irregular iris
shallow anterior chamber

Question 12

pharmacological tx of corneal defects and foreign bodies

Answer 12

supportive care
- pain relief: oral analgesics
- prevent bacteria superinfection
topical antibiotic ointment
lubricating drops/ointment
Pressure patching should be avoided
Steroids contraindicated
Topical anesthetics should never be used/Rx’d for pain

Question 13

corneal epithelium follow up (RSVP)

Answer 13

seek urgent ophthalmology eval if:
R: redness- sudden
S: sensitivity to light or Secretion
V: decreased Vision
P: Pain

Question 14

Chemical injury tx

Answer 14

immediate irrigation
- Alkali injuries -> rapid damage: saponification of fats and denaturation of collagen -> penetration of the anterior chamber and damage to intraocular structures
- Acid: cause corneal surface proteins to coagulate and create a barrier that prevents deeper penetration

Question 15

Recurrent corneal erosion syndrome

Answer 15

spontaneous erosion occurs at the site of a previous injury weeks to months later

Question 16

dry eye syndrome

Answer 16

multifactorial disorder characterized by abnormalities in the tear film
-> damage to the ocular surface

Question 17

dry eye patho

Answer 17

maintained by autonomic and reflexive functions of the peripheral and motor nervous system
3 layers:
- inner mucin layer
- intermediate aqueous layer
- outer lipid layer: meibomian gland production: limits evaporative loss of the underlying aqueous layer between blinks

Question 18

2 categories of dry eye

Answer 18

aqueous-deficient
evaporative dry eye

Question 19

aqueous deficient dry eye

Answer 19

typically localized to the lacrimal gland
gland insufficiency may be caused by:
- Sjogren disease
- other infiltrative diseases
- primary hyposecretion

Question 20

evaporative dry eye

Answer 20

Causes:
- meibomian gland dysfunction: obstructed
- poor eyelid closure
- inadequate blinking
- ocular rosacea

Question 21

Inflammation and dry eye

Answer 21

inflammatory cytokines affect tear film osmolarity
-> inc. tear film instability and evaporative loss
-> further inflammation

Question 22

dry eye s/s

Answer 22

dryness
foreign body sensation
burning
stinging
itching
ocular fatigue
redness or light sensitivity
transient blurred vision relieved by blinking
- worse with activities requiring visual concentration
- Paradoxically: some patient have hypersecretion of tears

Question 23

Medications that can lead to dry eye

Answer 23

anticholinergics
alpha blockers
antihypertensives: diuretics, beta blockers
oral corticosteroids
vitamins

Question 24

Auto-immune disorders and dry eye

Answer 24

lupus
rheumatoid arthritis
-> secondary sjogren syndrome
Thyroid eye disease

Question 25

Other causes for dry eye

Answer 25

• Cranial nerve VII palsy: eyelid malposition, poor closure
• Reactivation of vericella zoster in ophthalmic division
• dec. corneal sensitivity and lower blinking rate

Question 26

dry eye physical exam

Answer 26

visual acuity
inspect: ocular adnexa
Cranial nerve V and VII function

Question 27

Schrimer test

Answer 27

assess aqueous production:
ABNORMAL= aqueous deficient dry eye
- narrow piece of filter paper placed in inferior cul-de-sac
- tear production measured by how wet the paper is after 5 minutes.
– less than 5mm (w/ anesthesia) or less than 10mm (without anesthesia) is considered abnormal

Question 28

Tear breakup time

Answer 28

fluorescein dye instilled and the tear film is visualized with blue filter
- amount of time between the last blink and the first discontinuity in the tear film is recorded
- less than 10 seconds is abnormal
ABNORMAL = evaporative dry eye

Question 29

OSDI

Answer 29

Ocular Surface Disease Index
patient symptom questionnaire to assess dry eye severity and to monitor patient response to tx

Question 30

Dry eye tx

Answer 30

Nonpharm:
- lifestyle or workplace modification
- avoid windy, smoky, low-humidity environments
- lid hygiene: warm compresses and gentle lid scrubs with baby shampoo
Pharmacological:
- artificial tears
- gels/ointments provide better tear retention but cause visual blurring
- Drops with vasoconstrictive agents discouraged d/t rebound vasodilation and conjunctival injection

Question 31

complications from dry eye

Answer 31

chronic changes in corneal nerve morphology and neuro-transmission
chronic neuropathic ocular pain
conjunctival adhesions
scaring and neovascularization of the cornea
exposure to the ocular surface -> corneal thinning, ulceration, and infection

Question 32

corneal ulcer

Answer 32

deeper, involves underlying stromal layer

Question 33

hypopyon

Answer 33

pus in anterior chamber of eye