Chapter 26 Opthalmic Surgery
entropion
- an abnormal inversion of the lower eyelid - goal of surgery is to restore the eyelid to correct anatomical position by resection
Refraction
- bending of light rays through a transparent medium; occurs as light enters the front of the eye and passes through the lens - test for visual acuity, performed using a phoropter
primary open angle glaucoma
- chronic disease occurring in both eyes - the outflow of aqueous humor is obstructed in the trabecular meshwork , which can be caused by different factors
cornea
- clear tissue layer overlying the front of the eyeball - light enters the eye through the ______ - no blood vessels - composed of 3 tissue layers: epithelium ( superficial), stroma, and the endothelium
enucleation
- complete removal of the eyeball - performed to treat intraocular malignancy
opthalmoscope
- direct examination of the eyes is performed using an __________ - handheld instrument that magnifies the focal point, allowing the examiner to evaluate the fundus and other internal eye structures
ectropion
- drooping of the lower eyelid - creates an overflow of tears and exposes the conjunctiva, which becomes dry and irritated - outwardly turned eyelid
ciliary body
- extension of choroid, located at the periphery of the anterior choroid - composed of smooth muscle tissue to which suspensory ligaments are attached
choroid
- highly vascular pigmented - function is to prevent the reflection of light within the eyeball
retina
- innermost layer of the posterior globe - photoreceptive layer of the eye; it receives and transmits images to the brain via the optic nerve
sclera
- is a thick, white, fibrous tissue that encloses about three fourths of the eyeball - contiguous with the cornea at the front of the eye - communicates with the optic nerve sheath
phacoemulsification
- is the fragmentation of tissue by ultrasonic vibration - most common form of cataract removal - the goal of cataract extraction is to remove an opaque lens ( cataract ) and replace it with an intraocular lens ( IOL )
lens
- lies directly behind the iris in the anterior chamber - clear biconvex disc contained in a transparrent capsule
sclersl buckling surgery
- performed when the sensory layer of the retina becomes separated from the pigment epithelial layer - goal is to restore the layers to their normal positions and prevent blindness
penetrating technique ( full thickness )
- the anterior chamber is entered, and the full thickness corneal graft is transplanted - two Mayo set ups
lamellar ( partial penetrating )
- the anterior chamber is not entered, and one half to two thirds of the cornea is transplanted
beam splitter
A device that transmits an image from the primary ocular to an observer tube, producing an is identical picture.
zoom lens
A lens that increases or decreases magnification and is operated by the foot pedal.
coaxial illuminator
A light source (usually fiberoptic) transmitted through the lens or body of the microscope. It illuminates the area in the field of view of the objective lens.
Broad-field viewing lens
A low-power magnifying glass attached to the front of the oculars that produces an overview of the field.
X-Y attachment
A mechanism that allows the scope to move precisely along a horizontal plane.
Assistant binoculars
A separate optical body with a nonmotorized, hand controlled zoom.
Rhegmatogenous detachment
A tear in the retina
Hyphemia
Bleeding into the anterior portion of the eye
cataract surgery
During __________, the initial incision is made in the limbus where the two tissue meet
penetrating keratoplasty
Full-thickness transplantation of a donor cornea to restore vision
Paraxial illuminators
One or more light tubes that contain incandescent bulbs and focusing lenses. Light is focused to coincide with the working distance of the scope.
trabeculectomy
Performed to create a channel from which the aqueous humor may drain from the anterior chamber. Used in treatment of glaucoma.
anterior vitrectomy
Performed to remove the vitreous from the anterior chamber
Ocular or eyepiece
The component of the microscope that magnifies the field of view.
dacryocystorhinostomy
The creation of a permanent opening in the tear duct for the drainage of tears
Illumination System
The lighting system of the microscope.
Ophthalmic ultrasonography
Used to measure the density of the eye tissue and detect abnormalities.
aqueous humor
a clear fluid produced by the ciliary epithelium called ___________, fills the anterior chamber
Glaucoma
a group of diseases characterized by optic nerve damage and visual field loss
compound miscroscope
a microscope that uses two or more lenses in a single unit
primary angle closure glaucoma
a sudden rise in IOP is caused b total blockage or obstruction of the aqueous humor at the root of the iris
canthus
each juncture of the eyelids is called a __________
congenital glaucoma
fluid drainage system is abnormal at birth
Cryotherapy
freezing of tissue
strabismus
is a condition in which the eyes are unable to focus on point because the muscles lack coordination
macula
is a distinct area of acute vision that lies near the optic nerve
iris
is a pigmented membrane composed mainly of muscle tissue that surrounds the pupil
Dacrocystitis
is an inflammation of the lacrimal sac, causing pain, redness, and swelling at the site of the medial cathus
chalazion
is an inflammatory benign growth that originates in a sebaceous gland of the eyelid
pupil
is the only passageway between the two chambers
diathermy
mild heat created by diathermy of unit or laser
palpebral
refers to the eyelids
Normal tension glaucoma
retinal damage and visual field loss with migraine and optic disc hemorrhage
bony orbit
the basic structure of the eyeball, the globe, is contained within the orbital cavity also called __________
fovea centralis
the center of macula is called the _______
tarsal plate
the eyelids are composed of fibrous connective tissue referred to as the _________ covered with skin
lacrimal punctum
the lacrimal ducts extends from the inner canthus to the lacrimal sac. The opening of each duct is called the _________
zonules
the lens is held in place by suspensory ligaments called ________, which are attached to the capsule and ciliary body
objective lens
the lens that establishes the working distance and produces the greatest magnification
magnifying power
the magnification specification of a lens
optic disc
the optic nerve exits the globe in an area of dense neurons called the _________
Evisceration
the outer shell of the sclera and the muscle attachments are left intact
bulbar conjunctiva
the palpebral conjunctiva is a thin, transparent mucous membrane that lines each eyelid and reflects onto the globe, where it is called the ___________
vitreous
the posterior cavity lies at the back of the eyeball and contains a gel called ________
palpebral fissure
the space or interval between the upper and lower lids is called the _________
phoropter
this device has a range of corrective lenses that allows the patient to compare different combinations while viewing an eye chart
fluorescein angiography
used extensively in the diagnosis and evaluation of retinal and choroid diseases; it delineates areas of abnormality and is essential for planning laser treatment of retinal vascular disease
slit lamp
used to examine the anterior chamber of the eye
tonometer
used to measure the intraocular pressure ( IOP )
fluorescein
used to stain the cornea and highlight irregularities of the epithelial surface