II Lecture Chapter 16 Ophthalmic Internal Procedures pp 364

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41 Terms

1
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describe the type of drape used to fit the eye

adhesive backed, clear, aperture or incisable drapes

2
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describe a loop

an instrument used by the surgeon that are mounted on a pair of glasses and are used for magnification

3
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what is the purpose of Weck-Cel sponges

to help suck up fluid/blood in eye surgery

4
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why are powder free gloves typically used for eye surgery

the powder from the gloves can create corneal irritation

5
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what is a caliper used for

measuring the incision or open the incision more in preparation of placing a lens

to measure the distance from the original point of insertion to the new one

to verify the correct size of the cornea

6
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describe how draping is completed for a procedure that enters the ocular orbit

adhesive-backed, clear, aperture or incisable drape that covers the patients head and upper body

7
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how can you prevent damage or lint when placing microinstrumentation on your Mayo stand

covering the Mayo stand with a clear, plastic, sterile x-ray cassette cover reduces dust on the instruments as well as reduces the risk of microinstrument damage

8
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how is the eye stabilized while the surgeon works on it

a Flieringa ring is sutured on the patient's eye with a 5-0 or 6-0 nylon

4-0 sutures

4-0 silk sutures are placed in the superior rectus muscle for traction

9
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glaucoma: what fluid is affected and where

glaucoma-raised intraocular pressure or IOP

the inability of the aqueous fluid to exit the eye at the correct angle due to blockage by the iris which can damage the optic nerve and retinal blood supply, resulting in loss of vision

10
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glaucoma: what canal is blocked, causing an increase in intraocular pressure (IOP)

the canal of Schlemm (or a weakening of the trabecular meshwork)

11
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glaucoma: why does the increase in IOP lead to blindness

it applies pressure to the optic nerve and damage to the retinal blood supply which leads to ischemia and death of the nervous layer

12
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iridectomy

the surgical removal of a portion of the tissue of the iris: it creates a small hole in the peripheral portion of the iris to connect the posterior and anterior chambers of the eye, permitting the iris to fall back away from the trabecular meshwork, opening the angle of the anterior chamber to allow the outflow of the aqueous fluid through the Schlemm canal

13
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trabeculectomy

surgical creation of an opening that allows aqueous humor to drain out of the eye to underneath the conjunctiva where it is absorbed

14
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describe Tenon's capsule, the purpose of the capsule, and how it is incised

a thin membrane which envelops the eyeball from the optic nerve to the limbus, separating it from the orbital fat and forming a socket in which it moves

the Tenon capsule, also known as fascia bulbi or bulbar sheath, functions as an extraocular muscle pulley. it also provides a socket which separates the globe from the surrounding fat and allows free movement

Tenon's capsule is dissected free from the sclera with forceps and Westcott scissors toward the limbus to create a Tenon capsule-conjuctiva flap

15
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what are the drugs 5-FU and mitomycin used for? how are they used?

5-FU and mitomycin are antimetabolites and must be disposed of as hazardous waste due to their toxicity

5-FU is fluorouracil (a chemotherapy agent)

mitomycin is an antibiotic

the surgeon may use a soaked sponge left in place 1-5 minutes then removed

16
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describe what happens when a retinal detachment occurs

the liquid in the vitreous cavity passes through a retinal tear, separating the retina from the choroid

17
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identify and describe the procedure used to treat retinal tears

scleral buckling procedure

a) diagram

b) diathermy to mark area

c) sponge sutured in place

d) silastic band to support buckle

e) incisions in sclera and choroids to facilitate drainage of subretinal fluid

18
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how are cryotherapy and diathermy used in the treatment of a retinal detachment

diathermy marks areas of tears

cryotherapy seals the tears

19
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what intraocular gases may be used in the treatment of retinal tears

an intraocular gas may be injected to create pressure on the retina; long-acting gases require special head posture from a few days up to two weeks

types of gases include:

perfluoropropane (C3F8)

Sulfur hexafluoride (SF6)

20
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what is the purpose of the intraocular gas that may be injected during the procedure for retinal tears

to create pressure on the the retinato push it back into place while subretinal fluid is reabsorbed and scars form

21
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why would a vitrectomy be performed with this procedure (retinal detachment)

to remove the blood so that the surgeon can view whether a retinal tear or detachment has occurred

22
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where is the incision for a vitrectomy made

a sclerotomy is performed into the globe through the pars plana aka vascular tunic

23
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what else can be used to replace the vitreous humor

silicone oil, intraocular gases, viscoelastic agents (Viscoat, Healon)

gaseous or liquid

intraocular gases

silicone oil

endophotocoagulation

lensectomy

Sodium hyaluronate

saline

24
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what is the vitrector used for

vitrector units can infuse, cut, and aspirate

a tool used to cut the vitreous humour for subsequent removal during a vitrectomy

25
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list three indications for enucleation

an excision of an eye due to:

1. malignant neoplasm

2. penetrating wounds

3. extensive damage where no vision can be regained

26
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describe the difference between enucleation and evisceration. identify which one has better cosmetic effects

enucleation is excision of the eye. attachments of the globe are seperated. optic nerve is transected

evisceration allows the retention of the sclera and extrinsic muscles of the eye. it eliminates corneal sensitivity and allows the patient to wear a prosthetic eye that will have mobility and a better cosmetic result

27
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what types of implants may be used? why is a donor sclera sometimes used?

ocular implant

hydroxyapatite implant

donor sclera is used to create a flap in glaucoma filtering procedures. this simple technique is helpful when the sclera is too thin to safely and effectively form an adequate scleral flap. the use of donor sclera allows the procedure to continue as a guarded procedure and prevents early postoperative hypotony.

28
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describe three reasons for cataract formation

1) age

2) trauma

3) exposure to harmful chemicals

4) drugs

5) exposure to excessive sunlight

6) congenital disease

29
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describe the formation of a cataract and the symptoms it causes

the lens gradually clouds, less light is able to pass through, blurring and distorting images received by the retina, vision is gradually impaired, untreated causes needless blindness

may be white or yellow or brown

may form in nucleus of lens, outer cortical region, or entire lens

30
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describe two methods of cataract extraction

intracapsular cataract extraction: involves a large incision and the entire capsule is removed; suturing is required for closing the incision

extracapsular cataract extraction: performed through a small incision and only the lens is removed; incision is self-sealing with no sutures required

31
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describe the incision made for cataracts that is self-healing

extracapsular cataract extraction: performed through a small incision and only the lens is removed; incision is self-sealing with no sutures required

32
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where is the corneal limbus?

the border of the cornea and the sclera (the white of the eye). The limbus is a common site for the occurrence of corneal epithelial neoplasm. The limbus contains radially-oriented fibrovascular ridges known as the palisades of Vogt that may harbour a stem cell population.[1] The palisades of Vogt are more common in the superior and inferior quadrants around the eye.[2] Aniridia, a developmental anomaly of the iris, disrupts the normal barrier of the cornea to the conjunctival epithelial cells at the limbus.

33
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phacoemulsification (PHACO) may be used. describe how the machine works

a variation of the irrigation/aspiration technique. the tip of the phaco handpiece is inserted through the small incision and ultrasonic energy fragments the lens while simultaneously irrigating and aspirating the fragments. after the nucleus of the lens is removed, the irrigating/aspirating unit is used to remove the remaining pieces of cortex

34
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what is acetylcholine used for? what classification does that make acetylcholine?

injected into the anterior chamber through a fine cannula (30 gauge) at the graft margin (during a keratoplasty aka corneal transplant)

a compound that occurs throughout the nervous system, in which it functions as a neurotransmitter

35
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describe the purpose of the cornea

the cornea allows light into the eye and bends the light rays to help the lens focus them upon the retina

36
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describe four causes of corneal clouding

1) eye injuries

2) bacterial, biral, or fungal infections

3) corneal dystrophies

4) cataract or other eye surgery

37
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what type of instrument is a trephine and what procedure is it used for

a cylindrical saw for cutting a circular piece of bone

used in corneal procedures

38
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how long can the donor cornea be stored

up to 14 days

39
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how can you ensure proper fit of the cornea during a keratoplasty

the donor cornea is sized 0.1 mm larger than the recipient opening to ensure proper fit. the surgeon may request a separate sterile table for donor cornea preparation

40
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when might rejection of a donor cornea occur

rarely occurs within two weeks and may occur as late as 20 years following corneal transplant

41
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what is the purpose of applying fluorescein to the cornea? what tool must be used in conjunction with fluorescein?

fluorescein is a diagnostic agent used topically to mark tissue

fluorescein is used for detection of corneal abrasion or to access lacrimal duct patency

a diagnostic tool used in diagnosing corneal abrasions, corneal ulcers and herpetic corneal infections.

Woods lamp (ultraviolet light) or black light aids in diagnosis