Anatomy of the Eye Flashcards
VF
Visual Field
tr
Trace
t.i.d.
Three Times Daily
stat.
At Once
SC
Without Correction
RAPD
Relative Afferent Pupil Defect
q.2h.
Every Two Hours
qhs
Nightly
q.h.
Every Hour
q.i.d.
Four Times Daily
qd
Daily, Once A Day
PO
Orally, By Mouth
PH
Pinhole
OU
Both Eyes (Oculi Unitas)
OS
Left Eye (Oculi Sinister)
OD
Right Eye (Oculus Dexter)
NV or nVA
Near Vision
NPC
Near Point of Convergence
NPA
Near Point of Accommodation
mm
millimeter
mg
milligrams
NLP
No Light Perception
LP
Light Perception
CL
Contact Lens
CF
Counting Fingers
CC
With Correction
b.i.d.
Twice Daily
A.I.D.E.T.
Acknowledge, Introduce, Duration, Explanation, Thank You
OLD CART
Onset, Location, Duration, Context, Attributing, Relieving, Timing
5 Layers of Cornea Cells
Epithelium, Bowman’s Membrane, Stroma, Descemet’s Membrane, Endothelium
Aberration
The failure of a refracting surface or lens to produce an exact point-to-point correspondence between an object and its image.
Ablation
Removal of all or part of an object, usually from the surface inward.
Accommodation
Adjustment by the eye for seeing at different distances, accomplished by changing the shape of the crystalline lens through action of the ciliary muscle.
Adnexa
The tissues and structures surrounding the eye: eyelids, orbit, extraocular muscles, and lacrimal system.
Amblyopia
Decreased visual acuity without any apparent disease of the eye.
Ametropia
Any optical error of the eye that can be corrected by glasses or contact lenses. See Refractive error.
Anterior Chamber
The area between the inner-most layer of the cornea and the iris.
Anterior Chamber Angle
The junction of the cornea and the iris.
Anterior Segment
Front portions of the eye including the cornea, the anterior chamber, the iris, and the crystalline lens.
Aphakia
Absence of the crystalline lens of the eye, usually as a result of cataract surgery.
Aqueous Humor
Clear watery fluid, which fills the anterior chamber of the eye.
Astigmatic Keratotomy (AK)
Surgical procedure where incisions are made in the cornea to correct astigmatism.
Astigmatisim
Distortions in the cornea , or sometimes the lens, that focus light rays at different lengths, making it difficult to focus at any distance well.
Automated Lamellar Keratoplasty (ALK)
A surgical procedure for correcting high myopia by removing and folding back a layer of the anterior cornea, removing a precise amount of corneal tissue with an automated microkeratome, and folding back into position the first layer without stitches.
Autorefraction
An automated objective refraction that measures each eye individually without patient response or interaction.
Axis
An axis is a line dividing a regular figure symmetrically. As used in optometry, two axes define the direction of the longest and shortest radii of an oval (astigmatic) lens system of the eye. Common usage refers to the longer axis of a lens, the direction of least power, as the cylinder axis.
Best Corrected Visual Acuity (BCVA)
The best vision the patient can achieve when they are using the most updated prescription.
Bifocal
A lens with two optical zones, one for near vision and one for distance vision.
Bilateral
Relating to or affecting both right and left eye.
Binocular Vision
The ability to use both eyes simultaneously to focus on the same object and to fuse the images from both eyes into a single image.
Biometry
Either ultrasound or laser light used to measure the length of the eye to calculate power needed for IOL placement.
Biomicroscope
See Slit Lamp
Blindness
Having central vision acuity of 20/200 or less in the better eye after correction; or having visual acuity of better than 20/200, but having a field of vision of no greater than 20 degrees (legal definition).
Bulbar Conjunctiva
The portion of the conjunctiva that covers the outer surface of the globe (eyeball).
Canaliculus (canaliculi)
Tubes connecting the eye to the lacrimal sac. The puncta are the openings of the canaliculi.
Canthus
The angle formed by the meeting of the upper and lower eyelids, specified as outer or temporal, and inner or medial (nasal).
Capsular Tension Ring
PMMA ring inserted into capsular bag to stabilize capsule to withstand the pressures of cataract surgery.
Cataract
Opacity or clouding of the natural crystalline lens, causing foggy vision. Symptoms may include necessity of more light to read, more difficulty driving at night due to glare from headlights, or loss of contrast sensitivity.
Choroid
Continuation of the ciliary body in the form of a layer of tissue that lies between the sclera and the retina, which furnishes nourishment to the other parts of the eyeball.
Cilia
Technical term for eyelashes.
Ciliary Muscle
Muscle fibers in the ciliary body.
Ciliary Body
Band-like structure of muscle and secretory tissue that extends from the edge of the iris and encircles the inside of the sclera toward the front of the eye.
Ciliary Processes
Inner surface of the ciliary body that is arranged in folds, rows or ridges. This structure secretes the aqueous humor.
Collagen
A protein found in connective tissues which is relative inelastic but has high tensile strength.
Computerized Corneal Topography (CCT)
Measurement to map exact areas and degree of corneal astigmatism.
Concave Lens
A lens having a surface that is rounded inward, to produce focal power that diverges parallel rays of light. Also called a diverging, myopic, or minus lens, denoted by the minus sign.
Cone
One of the two types of light-sensitive cells in the eye. Cone cells are concentrated in the center of the retina and are responsible for color vision.
Congenital
Present at birth.
Conjunctiva
Thin, translucent layers of mucous membrane, which lines the eyelids and covers the front part of the eyeball, excluding the cornea.
Conjunctivitis
Inflammation of the conjunctiva
Contact Lens
A lens constructed to fit directly on the eyeball.
Contrast Sensitivity
A measurement, which determines the ability of the observer to see a wide range of everyday objects under normal and reduced illumination conditions.
Convergence
The process in which the visual axes of the two eyes are directed toward to same near point, with the result that the eyes are turned inward.
Convex Lens
A lens having a surface that is curved outward to produce focal power that converges parallel rays of light to a focus. Also called a converging, hyperopic, or plus lens, denoted by the plus sign.
Cornea
Referred to as the “window of the eye”. It provides most of the focusing power when light enters the eye. The cornea is composed of 5 layers of tissue. The outer layer (the epithelium) is the eye’s protective layer. This layer is made up of a highly regenerative cells that have the ability to grow back within three days. You generate a completely new epithelial layer every five days. This allows for fast healing of superficial injuries to the cornea. Most of the inner layers provide strength to the eye.
Crystalline Lens
A transparent lens suspended inside the eye immediately behind the iris, which brings rays of light to a focus on the retina.
Cycloplegic
A drug that temporarily puts the ciliary muscle at rest and dilates the pupil, often used to ascertain the error of refraction. Administered in the form of drops. See Cycloplegic refraction.
Cylindrical Lens
See Toric lens
Depth Perception
The ability to preceive the relative positions of objects in space. See Stereoscopic Vision.
Dilate
To spread wide, enlarge, or expand. In eye care, dilation describes the degree of opening of the pupil. The pupil can be further dilated by the instillation of cycloplegic drops.
Diopter
A unit of measurement of strength or refractive power of lenses. Can also refer to the relative curvature of a lens surface.
Emmetropia
The focal condition of the normal eye in which there is no refractive error.
Endocyclophotocoagulation (ECP)
A laser attached to a camera used to ablate ciliary processes to reduce pressure inside the eye by decreasing aqueous production.
Epithelium
a clear outer protective coating that covers the cornea, conjunctiva, and inner eyelid.
Esophoria
A tendency of an eye to turn inward when covered.
Esotropia
A condition in which one or both eyes turn too far inward, sometimes called convergent strabismus or crossed eyes.
Exophoria
A tendency of an eye to turn outward when covered.
Exophthalmos
An abnormal protrusion of the eyeball.
Exotropia
A condition in which one or both eyes turn too far outward, sometimes called divergent strabismus.
Extraocular Muscles
External muscles attached to the outside of the globe that are responsible for turning and rotating the eye. Each eye has four rectus and two oblique muscles.
Eyelids
Moving folds of the skin that cover the outer portion of the eyeball. The eyelids protect the eye from injury and aid in the lubrication of the eye’s surface.
Farsightedness
A refractive condition of the eye, resulting from the tendency of rays of light to focus behind the retina when accommodation is relaxed. In mild amounts this can cause blurred vision at near point. In higher amounts of vision is blurred at a distance.
Field of Vision
The entire area, which can be seen without shifting gaze.
Floaters
Small particles consisting of cells or fibrin, which move in the vitreous.
Focal Length
the distance between a lens and the position where the lens brings parallel light rays to a focus.
Focal Point
The position on the optical axis of a lens where parallel light rays are brought to a focus.
Focus
the point to which rays are converged after passing through a lens.
Fogging
A technique in subjective refraction of moving the refractive lens in a plus direction to initially cause a blurred image. The eye tries to compensate for the blur, and when the lens is changed to approach the correct refraction, the eye is more relaxed and the refraction can be better refined.
Fornix
The area where the palpebral and bulbar conjunctiva meet
Fovea
A small depression in the central retina at the back of the eye. The part of the macula adapted for most acute vision.
Fundus
The back of the eye, which can be seen with an ophthalmoscope.
Fusion
The power of coordinating the images received by the two eyes into a single mental image.
Gas Permeable Lens
Contact lenses that allow oxygen and carbon dioxide to pass through them. Usually refers to a type of hard lens (RGP), although soft lenses are also gas permeable.
Glaucoma
A progressive disease of the eye, which is characterized by pressures inside the eye being too high and causing the nerve fibers running through the optic nerve to slowly deteriorate. There is no cure for glaucoma. It is managed with various treatments including drops, laser treatment and traditional surgery. A patient with glaucoma is not a candidate for laser vision correction.
Globe
More commonly known as the eyeball
Halo
A hazy ring around bright light, seen by some patients with refractive error.
Haze
A clouding of vision sometimes reported following Laser-PRK. The condition usually corrects itself, after a period ranging from weeks to months.
Hypermetropia
See farsightedness.
Hyperopia
Farsightedness. The length of the eye is too short and the light rays are focusing too far behind the retina. Farsighted patients have trouble with near tasks and close up vision can be nonexistent or difficult. Distance vision may also be affected but it is usually clearer than the near vision when comparing the two.
Hypertropia
A condition in which one eye deviates upward.
Inferior Oblique
One of the six muscles of the eye that moves the pupil up, away from the midline and the top of the pupil aware from the nose.
Inferior Rectus
One of the six muscles of the eye that allows rotation around all three axes and moves the pupil down and towards the midline and the top of the pupil away from the nose.
Injection
A term sometimes used to mean congestion of ciliary or conjunctival blood vessels; redness of the eye.
Instillation
The process of placing drops on the surface of the eye through retraction of the lower lid.
Intraocular Lens (IOL)
An artificial lens put in the eye to replace the natural crystalline lens.
Intraocular Pressure (IOP)
The pressure of the contents of the eyeball. Increased IOP can be an indicator of an unwanted steroid response, which can lead to secondary glaucoma.
Iris
The ‘colored’ portion of the eye. This muscle actually contains a contracting and an expanding muscle within it. It regulates the amount of light that enters the eye and controls the size of the pupil with its movements.
Iritis
Inflammation of the iris, a condition marked by pain, discomfort from light, contraction of pupil, and discoloration of iris.
Jaeger Test
A test for near vision, lines of reading matter printed in a series of various sizes of type.
Keratitis
An inflammation of the cornea.
Keratoconus
A deformity in which the corneal curvature gets progressively steeper, making the cornea somewhat cone shaped.
Keratometry
The measurement of the anterior curvatures of the cornea with a keratometer.
Keratometer
An instrument used to measure the radius of the anterior surface of the cornea, and the power and axis of the corneal cylinder if present. It utilizes the mirror effect of the front surface of the cornea.
Keratoplasty
The graft of a donor cornea to replace a damaged or diseased one.
Lacrimal Apparatus
The orbital structures that produce tears and the ducts that drain excess fluid from the front of the eyes into the nose.
Lacrimal Gland
Part of the lacrimal apparatus that produces tears. It is located in the lateral part of the upper lid just under the orbital rim.
Lacrimal Sac
Collection chamber for tears after they have left the eye and traveled through the canaliculi.
LASIK
LASIK or Laser In-Situ Keratomileusis, is a surgical procedure to reduce refractive errors that cause near-sightedness, far-sightedness, and astigmatism, conditions that re historically corrected by spectacles or contact lenses. First, the inner layers of the cornea are gently separated from the outer layers with a micro-surgical instrument. Next, a cool ultraviolet laser applies pulses of energy on those inner layers of the cornea to slightly reshape and thin it. Because the cornea accounts for approximately 70% fo the eyes total light bending ability, slight changes can dramatically reduce an individuals continued dependence on corrective lenses.
Laser Thermal Keratotomy (LTK)
Applying focalized light energy to the peripheral cornea to correct hyperopia (farsightedness).
Lateral Canthus
The outer (temporal) side fo the palpebral fissure.
Lateral Rectus
One of six ocular muscles, which controls rotation around the vertical axis and moves the pupil away from the midline.
Lens
The lens is the clear structure located behind the pupil. Its primary function is to provide fine tuning for focusing and reading. The lens preforms this function bu altering its shape. At about the age of 40 to 50, the lens becomes less flexible and presbyopia begins. At abut the age of 60 to 70, the lens becomes cloudy and hard which prevents light from entering as well. This condition is called cataract.
Limbus
The junction between the cornea and sclera.
Macula
The small area of the central retina that surrounds the fovea which contains yellow pigment. This region provides the most distinct vision in the retina.
Maifest Refraction
A subjective refraction without use of cycloplegic drops.
Manual Refraction
A subjective refraction that measures each eye individually and together with patient interaction and response.
Medial Canthus
The inner (nasal) side of the palpebral fissure.
Medial Rectus
One of the six muscles of the eye that controls rotation around the vertical axis and moves the pupil towards the midline.
Microkeratome
An incision device that removes precise amounts of surface of the cornea used for LASIK surgery.
Miotic
A drug that causes the pupil to contract.
Monovision
A type of corrective procedure in which one eye is corrected for distance vision and the other is corrected for near vision.
Mydriatic
A drug that dilates the pupil.
Myopia
Nearsightedness. The eye is too long and the light rays are focused too far in front of the retina. Nearsighted patients have very little trouble seeing up close but distance vision is blurry.
Nasolacrimal Duct
The duct containing the lacrimal sac and the nasal cavity. Tears passed through the nasolacrimal duct after leaving the lacrimal sac.
Near Point of Accommodation
The nearest point at which the eye can perceive an object distinctly. It varies according to the power of accommodation.
