Test 2 Flashcards
how does the conjunctival epithelium heal?
migration of cells and mitotic proliferation
how long does it take to re-epithelialize conjunctival wounds?
wounds as large as 1 cm can be healed within 48-72 hours
what layers of the cornea do we look for through the slit lamp?
tear film (movement and appearance), epithelium, bowman’s layer, stroma, descemet membrane, endothelium.
what does the stroma of the cornea contain?
contains wbc, macrophages, lymphocytes, and PMN. this cannot regenerate after damage
What does the descemet membrane of the cornea contain?
It terminates at the limbus (schalbe’s line). This does have regenerative properties.
What does the endothelium of the cornea do?
maintains the dehydration of the cornea by pumping out the excess fluid from the stroma.
what is deturgescence?
a state of relative dehydration to keep the cornea transparent.
how long does it take for the entire corneal epithelium to turn over?
7-10 days. The superficial squamous cells heal by sliding off surrounding cells ( few hours). The cuboidal wing and basal cells heal within hours to days, and basal cells secrete basement membrane every 8- 12 weeks.
what does the corneal epithelial stem cells do?
they are located at the superior and inferior limbus at the palisades of vogt. They migrate into basement membrane and eventually to the superficial area and are shed off. They also act as a barrier to prevent conjunctiva from growing into the cornea.
What happens when there is a disfunction of the stem cells in cornea?
cornea becomes vascularized or conjunctiva starts growing into it.
what are organic FB?
from animal or plant origin. Eg: nuts, seeds, bones, branches, food or wood
what are inorganic non-metallic FB ?
objects not derived from living material. Eg: sand, plastic, stones, glass, soil.
CHx questions for circumstances surrounding the injury
CC = pain (most important), lacrimation, redness Onset – time/place, FLORIDA oIf more time has passed, could have traveled/embedded deep
Circumstances (extremely important) – what they were doing when it began can tell you type of FB and how far it has penetrated
actions taken in attempt to remove or relieve pain
what procedures must be done before removing foreign body?
Always take VA BEFORE and after removing FB oSc, cc, ph
Put anesthesia drop before if very painful, esp if in cornea
Check pupils and EOMs before and after
Look for circumlimbal flush (redness only at the limbus) –characteristic of uveitis
oCheck AC for cells/flares If chamber is shallow, AH could be leaking out Seidel test – put fluorescein and look for outflow
Evert lids, look for perforation oIf FB is in palpebral conj, may be difficult to see – stain with fluorescein to see its track of movement
Superior palpebral conj = most common FB location oMay have to double evert (UL and LL simultaneously) to find FB lodged in fornix – use a retractor or paper clip (video)
What can we do if there is a suspected Intraocular FB? (IOFB)
If you suspect IOFB (intraocular), dilate oXray, B-scan, UBM (ultrasound biomicroscopy), CT to see depth of FB NOT MRI, especially if metal FB.
Laser in vivo confocal microscopy (IVCO) HRT3
How are the instruments disinfected?
clean instruments from debris, then use cidex, or Opti Cide 3 (glutaraldehide 3%) or autoclave instruments.
cotton tip applicator
this must be used with saline if FB is superficial
Caution: this can disrupt the epithelium or cause FB to break apart. (irrigation)
Gulf Spuds
used to remove larger FBs they are safer than needles and are used to scoop out the FB.
needles
for smaller and more delicate fbs. used to remove symptomatic concretions and conjunctival cysts. do not come in perpendicular, come in from an angle.
CAUTION: can penetrate deeper layers so be careful. most commonly use 25 g
Alger brush
used for rust ring removal. is a hand held drilling burr. use in sweeping or circular manner and stops if too much pressure is applied. can also be used to create a smoother area in case of large, loose epithelium.
where is the most common place for FB location
superior palpebral conj.
when should lids be everted to look for FB?
when the symptoms suggest FB but cannot be seen.
when should lids be double everted?
to localize objects in the sulcus, or fornix
what symptoms should we look for in the anterior segment?
hyperemia, ischemia, chemosis, staining with fluorescein, epithelial compromise, corneal edema. IOP, punctate keratitis
what is a white quiet eye?
an eye that has chemically induced ischemia and cauterization can mask severe occult injury
removal of FB
determine: # of FB, location and degree of embeddedness.
when to give anesthesia
avoid it unless there is too much pain or fb is really deep
conjunctival FB removal technique
SL at 10-16 X diffused illumination at medium intensity.
how to use a spud to remove FB from conjunctiva
align spud close to eye from outside and then use slit lamp to loosen edges of FB. once periphery is loosened use flicking motion to lift off then irrigate. use spatula or forceps to remove residual particle matter.
what should be done if after thorough exam a FB cannot be found?
irrigate superior and inferior cul de sacs followed by swabbing with a moistened cotton tip the palpebral conj.
meds to use after FB removal
DO NOT GIVE topical anesthetic. Polytrim q6h, polysporin q 6h to q 12h. cyclopegics and pressure patches are rarely needed
cyclopegics after fb removal
elax accommodation (reduce pain) and inflammatory response Let pt know they will see blurry at near, photophobia
Follow ups after FB removal
conj usually heals within 12-24 hrs. if FB sensation persists RTC, then F/u 5-7 days
contraindications or complications of FB removal
2ry infections are possible. FB at the bulbar conj. may be a sign of perforating injury(Hx of hammering metal on metal or using high speed machinery as a grinding wheel). and perforating can be masked by SCH. SPK might happen after irrigation due to disruption of the cornea.
seidel test
helps in diagnosis radiological studies of the eye and orbit. refer if signs of perforation of globe are present.