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