Download Ophthalmic Lecture - JATC Surgical Technology

Ophthalmic Surgery
Eye Function
Sensory organ of
sight
Converts
environmental light
energy into
bioelectrical energy
Relays bioelectrical
energy to the brain for
interpretation
Orbit
Substantially
surrounded by bone
like the brain
Seven bones
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Frontal
Sphenoid
Ethmoid
Superior maxillary
Zygomatic (malar)
Lacrimal
Palintine (palate)
Muscles
Six with one primary
movement each
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Superior rectus-upward
midline
Inferior rectus- downward
midline
Medial rectus-midline
Lateral rectus-lateral
Superior oblique-downward
lateral
Inferior oblique-upward
lateral
Facts
Two check ligaments limit the movement
of the lateral and medial rectus.
5-10 muscle fibers in each muscle body.
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Smallest # of muscle fibers of any muscles in
the body.
Makes the eyes move together.
Binocular vision-corresponding cones and
rods in both eyes receive the same image
and send a stereoscopic image to the
brain for depth perception.
Lacrimal System
Lacrimal gland secretes
tears to keep the
conjunctiva moist
Excretory ducts convey
the fluid to the surface
of the eye.
Lacrimal canals carry
fluid away into lacrimal
sac into nasal cavity
Lacrimal sac is a dilated
segment of the nasal
duct.
Globe
External Tunic
Anterior portion of the
globe
Conjunctiva-mucous
membrane lining inner
surface of eyelid and
anterior sclera and
cornea
Sclera-opaque fiberous
membrane shaping the
globe
Cornea-transparent
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Degree of curvature varies
by individual
Rounder in youth then
flattens with age
Middle Tunic
Choroid
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Posterior 5/6 of eye
Thin vascular dark brown
membrane
Adhered to the sclera
externally
Internally adhered to the retina
Ciliary body –ring muscle
Iris-posterior to cornea and
anterior to the lens
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Perforated in center by pupil
In the aqueous humor
Contractile curtain
Interior Tunic
Retina-delicate nervous
membrane on which
images are received
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Continuous with the optic
nerve
Macula-oval yellowish
Central fovea located in the
center of the macula.
Consists only of cones. Spot
of most accurate vision
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Blind spot where optic
nerve sits
Contains no rods or cones
Crystalline Lens
Behind the pupil, in front
of the vitreous body.
Encircled by ciliary body.
Encapsulated in a
transparent, highly elastic
and brittle membrane
Biconvex body
Held in position by the
suspensatory ligament.
Lens projects image upside-down
on retina then brain turns it right
side-up again
Cavities and Chambers
Anterior Cavity-filled with
aqueous humor
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Anterior chamber-anterior
to iris
Posterior chamberposterior to iris, anterior to
lens
Posterior Cavity-filled with
vitreous humor
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All of the space posterior to
the lens, suspensatory
ligaments and ciliary body.
Maintains sufficient
pressure to maintain shape
of the globe
Prevents globe from
collapsing.
Ophthalmic Draping
http://one.aao.org/Assets/eyePop.html
Ophthalmic Pathology
Systemic
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Diabetes
Neurological
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Stroke or neoplasm
Trauma
Angle Closure Glaucoma
Inability of aqueous fluid flowing into the anterior
chamber to exit through the angle where the
cornea and iris meet because of a blockage by
the iris.
Increase in fluid places extreme pressure on the
optic nerve
Leading cause of blindness in the USA
Symptoms
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Sudden decrease in vision
Eye pain
Headache
Sensitivity to light
Nausea and vomiting
Rapid increases in intraocular pressure
Cataract
Crystalline lens becomes opaque
or cloudy due to age or trauma
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Injury, drugs, medications, harmful
chemicals, excessive sunlight,
congenital.
Condition, not a disease
Usually white but can be brown or
yellow
Limited light being received by the
retina blurs and distorts images
received by the retina
Retinal Detachment
Symptoms
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Flashes of light or large spots in vision
Flashes are caused by tugging of the vitreous
brain interprets this as flashing light
Spots are vitreous strings formed when pulling away from
retina
Small detachment repaired by cryotherapy or
laser
Large detachment
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Vitreous liquid can get under the retina separating it
from the choroid. Dark shadows or veil in vision.
Vitreous Hemorrhage
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Torn blood vessels of a retinal tear.
Vitrectomy performed.
Proliferative Vitreoretinopathy (PVR)
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Scar tissue
causes re-detachment of retina or puckers the
retina.
Traction Retinal Detachment
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Vitreous pulls on scar tissue causing
detachment.
Epiretinal Membrane
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Scar tissue that forms over the macula.
Corneal Pathology
Must be clear and of proper curvature to
function properly. Can be damaged by:
-Scar tissue from trauma
-Corneal infection (herpes)
-Corneal dystrophies
-Inherited corneal diseases
-Prior surgery
Can be replaced via corneal trasplant.
Chalazion
Chalazion-lump on inner or outer surface of
eyelid
Caused by an inflammatory reaction to material
trapped inside an oil-secreting gland in the
eyelid.
Pterygium
growth of conjunctiva
extending onto the cornea
Benign lesions
Can be caused by ultraviolet
light.
Most asymptomatic and
don’t require treatment.
Imflamation – steriod
Vision – surgical removal.
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Dissected away and
conjunctiva is sutured into the
bed.
Dacryocystitis
inflammation of lacrimal sac due to
obstruction of nasolacrimal gland.
Red and inflamed.
Mucous discharge of eye
Antibiotics
Severe cases- surgery
Strabismus
Misalignment or
deviation of the eyes
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Misalignment makes
binocular vision
impossible.
May become
amblyopic (lazy eye)
Diplopia (double
vision) may occur.
Esotropia-crossed eyes
Exotropia-wall eyes
Ophthalmic Medications
Mydriatic
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Cause mydriasis: pupil dilation (iris paralysis)
Allows patient to still focus.
Examine retina, removal of lens.
Pressure is placed on lacrimal gland to prevent rapid absorption.
Cycloplegic
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Cause mydriasis: pupil dilation (ciliary muscle paralysis)
Pressure is placed on lacrimal gland to prevent rapid absorption.
Viscoelastic
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expand the anterior chamber
Vitreous substitute
Miotic
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Constrict the pupil by acting on sphincter of iris.
Injection or topical application.
Decrease intraocular pressure by facilitating the drainage of aqueous
humor.
Laser iridectomy, glaucoma
Ophthalmic Medications
Hyperosmotic
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Diuretics to shrink the vitreous body
Reduce intraoccular pressure
Used to aid in scleral closure.
Anti-inflammatory agents
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Suppress inflammatory response.
Antibiotic ointment
Lubricant
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Protect cornea from drying out.
Tetracaine and proparacaine (no preservatives)
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Local anesthetic
can add Wydase or epi to prolong duration
Retrobulbar block- blocks both sensory and motor sensations.
Injecting area around optic nerve.
BSS
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Irrigating fluid to keep the exposed cornea moist
Special Considerations
Microscope
Patient is awake
Dark room
Specialized equipment
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Diathermy – miniature bipolar cautery
Cryotherapy- cold temperature CO2 gas used
to seal tears and holes.
Microscopic instrumentation
Eye bed
Surgical Interventions
Ptosis
Drooping of the upper eyelid.
Tarsus is secured to aponeurosis.
Entropion
Abnormal inversion of lower lid.
Eyelashes may rub against the cornea
causing irritation, pain and chronic tears.
Congenital- hypertrophy of oculi muscle
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Triangular wedge of skin, orbiularis oculi muscle
and tarsus
Involutional- weakness of lower eye muscles
and atrophy of orbital fat.
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Lateral canthotomy incision made
Lower lid skin incision made, fat excised.
Lid is pulled laterally to shorten.
Iridectomy and Trabeculectomy
Iredectomy- removal of a section of iris
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Relieves pressure buildup in glaucoma
patients.
Trabeculectomy-removal of spongy tissue
meshwork that drains the aqueous fluid
into the blood.
http://organizedwisdom.com/Trabeculecto
my
Trabeculoplasty
Treatment for open angle glaucoma.
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Creating a passage for quicker drainage of
aqueous humor.
Use of Laser to burn a space in the trabecular
meshwork.
Selective laser Nd: Yag (SLT)- selectively targets
pigmented cells.
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Reduces amount of scarring
Can be retreated many times
Argon laser (ALT)- evenly spaced burns
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Scars- making retreatment difficult.
http://www.seebetterflorida.com/website/EyeVideos/tabid
/90/Default.aspx
Strabismus Correction
Recession
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Muscle is recessed on the globe.
http://www.abcd-vision.org/kid-eyedisorders/MR%20Recess.html
Resection
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http://www2.medicine.mcgill.ca/strabismus/pr
ocedures_resection_lateral_rectus_non_djust
able.php
Adjustable suture surgery
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See above wesite.
Scleral Buckle
Localizing the position of all retinal breaks,
treating them with a cryoprobe, and
supporting them with silicone scleral
buckle.
Type and shape varies depending on
location and number of retinal breaks.
Buckle is sutured onto the sclera to create
an indentation (buckle) inside the eye.
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The buckle is positioned so that it pushes on
the retinal break and effectively closes the
break.
Scleral Buckle
Buckle (tire)
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Silicone bolster that
encircles the eye.
Cryo
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Band
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Silicone strip used to
keep buckle in place.
Diathermy
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Sleeve
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Slicone band used to
keep the two ends of
the band in place.
Used to freeze the
sclera over the area of
detachment.
High frequency
electro-surgery.
Indirect
opthalmoscope
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Headlight used to view
the retina with 20D
and 28D handheld
lenses.
Scleral Buckle
http://www.retinavitreous.com/vide
o%20files/intro_bucklevitrd0907.ht
ml
Dacryocystorhinostomy
Performed to assist in the drainage of
tears and secretions from the lacrimal sac
into the middle meatus of the nose by
forming a short circuit through the lacrimal
bone and the nasal mucosa.
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Performed when the nasolacrimal duct is
obstructed by fibrous tissue or bone.
Dacryocystorhinostomy
Local is administered
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Conjunctiva, nose, lacrimal crest.
Incision made
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Conforming to the anterior lacrimal crest.
Retractors are placed.
Lacrimal sac is separated from lacrimal
fossa.
Ostium is made.
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Use a punch, small oscillating saw or a bur.
Dacryocystorhinostomy
Window in bone is made and trimmed to
desired size.
Elevator is used to strip the nasal mucosa.
Vertical cut is made in anterior wall of the
lacrimal sac.
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Probe is passed through to test patency
Nasal mucosa and lacrimal sac are incised
horizontally and the nasal mucosa and the
lacrimal sac are joined.
Anterior wall incision closed. Skin closed.
Enucleation and Evisceration:
Traditional Approach
Enucleation is indicated for:
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Malignant neoplasm, penetrating wounds,
extensive damage (no vision can be regained)
Evisceration
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Allows retention of shrunken remnants of the
eye.
Eliminates corneal sensitivity
Allows patient to wear a prosthetic eye that
will have mobility and better cosmetic results.
Enucleation
http://www.youtube.com/watch?v=F3QSMy_bx-Q
Enucleation (hydroxyapatite)
With Plugs
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http://www.ioi.com/patient/video.htm
With Donor Sclera
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The implant is wrapped in donor sclera. This
allows the blood vessels to grow into the
porous coral material. The muscles that help
give movement to the eye are sutured to the
implant, which allows for some movement of
the prosthesis.
Evisceration
The painful red eye with corneal ulcer
Evisceration begins with 360 degrees
Contents are removed with an
evisceration spoon.
sclera is cleaned with chlorhexidine to
destroy any uveal tissue
The cornea is cut with the corneal scissors
The globe is replaced with a silicone
ball. The insertion is facilitated by
cutting the sclera radially.
The sclera is closed with 5/0 vicryl.
The conjunctiva is closed with 6/0 vicryl.
A conformer is inserted to prevent
contracture of the conjunctiva.
Keratoplasty (corneal
transplant)
Cornea
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Anterior window of the eye.
Allows light into the eye and bends (refracts)
the light rays to help the lens focus them upon
the retina.
For proper function it must be clear and of a
proper curvature.
Cloudy, damaged, or cone shaped corneas
will affect vision.
Cornea transplant can make a dramatic
improvement in vision.
Keratoplasty (corneal
transplant)
Transplant tissue
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Only the central part of the cornea is replaced
Comes from a donor
Eye bank procures tissue, examines, stores and
protects it until used
Tissue is extensively tested.
Comes as whole eye or prepared and sized corneal
button
Stored for up to 30 days
Refrigerated
Donor disk is punched 0.1 mm larger than the recipient
opening to ensure proper fit
Keratoplasty (corneal
transplant)
http://www.youtube.com/watch?v=qmTvIp
SfS-M&feature=related
http://www.youtube.com/watch?v=N2uM2
6GFRXs&feature=related
Cataract Extraction
Intracapsular cataract extraction
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Large incision in which the entire capsule is
removed.
Extracapsular cataract extraction
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Small incision in which lens is removed
manually or by phacoemulsification.
Phacoemulsification uses ultrasonic energy to
break up the lens, the lens material is irrigated and
aspirated simultaneously. The posterior capsule
remains intact.
Intraocular lens (IOL) is the placed.
Cataract Extraction
Intraocular lens
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Small prescription lenses placed inside the
eye during lens replacement or cataract
surgery.
Designed to replace the eye’s natural lens.
Corrects the eye’s existing refractive error
because of the corrective prescription power
of the lens.
Soft (foldable) or hard lenses.
Soft- rolled up and placed through a small incision.
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Made of silicone or acrylic
Hard-inserted through a slightly larger incision.
Cataract Extraction
http://www.youtube.com/watch?v=
poGJSFLmrnc
Vitrectomy
Microsurgical procedure in which
specialized microinstruments and
techniques are used to repair retina
disorders, many of which were previously
considered inoperable.
Vitreous gel is removed from the eye and
replaced with a special saline solution
similar to the liquid being removed.
A high intensity fiberoptic light source is
used to illuminate the inside of the eye.
Vitrectomy
Eye is entered at the pars plana (point
where iris and sclera touch).
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Approach avoids damage to the retina and
crystalline lens.
Cases commonly referred to as trans pars
plana vitrectomy.
Vitrectomy Techniques
Intraocular gases
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Usually perflouropropane (C3F8) or Sulfur
hexaflouride (SF6)
When mixed with sterile air, gas can remain in
the eye up to two months.
Eye’s own natural fluid will replace the gas.
Used for retinal detachments, and closer of
macular holes.
Patient must maintain certain head position.
May progress cataracts and elevate
intraocular pressure.
Vitrectomy Techniques
Silicone Oil
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Used for retinal detachments.
Remains in eye until it is removed.
Does not block vision like the gas does.
Positioning is less critical
May promote cataracts, cause glaucoma, and
damage the cornea.
Endophotocoagulation
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Laser used to treat intraocular structures.
Retina tears and proliferated diabetic
retinopathy.
Vitrectomy Techniques
Microsurgical instruments
Lensectomy
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Removal of the eye’s crystalline lens during a
vitrectomy procedure.
Done to gain adequate visualization of
structures or access into operative site.
Natural lens can be replaced with a clear lens
implant.
Usually performed using high frequency
ultrasound.
Vitrectomy terms
Gas forced infusion
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Method of maintaining intraocular pressure.
Ocutome
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Instrument that cuts/aspirates the vitreous.
Main panel controls the rates.
Fragmatome
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Ultrasonic instrument with aspiration to remove
the lens.
Membrane peeler/cutter (MPC)
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Microscissor used to cut and peel membranes
from the retina. Has aspiration capability.
Vitrectomy Terms
Endoilluminator
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For intraocular use.
Endo/exo cautery
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Low current cautery for use inside/outside
eye. Different tips are used for each.
Argon laser
Endo /indirect capability laser.
http://www.youtube.com/watch?v=iFcVCSRVGj
w
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