Eye Care Terms

Front 1

AXIS

Back 1

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 the least power, as the cylinder axis.

Front 2

BEST CORRECTED VISUAL ACUITY (BCVA)

Back 2

The best vision the patient can achieve when they are using the most updated prescription.

Front 3

BIFOCAL

Back 3

A lens with two optical zones, one for near vision and one for distance vision.

Front 4

BILATERAL

Back 4

Relating to or affecting both right and left eye.

Front 5

BINOCULAR VISION

Back 5

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.

Front 6

BIOMETRY

Back 6

Either ultrasound or laser light used to measure the length of the ye to calculate power needed for IOL placement.

Front 7

BIOMICROSCOPE

Back 7

See slit lamp.

Front 8

BLINDNESS

Back 8

Having central visual 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 that 20 degrees (legal definition)

Front 9

BULBAR CONJUNCTIVA

Back 9

The portion of the conjunctiva that covers the outer surface of the globe (eyeball).

Front 10

CANALICULUS (CANALICULI)

Back 10

Tubes connecting the eye to the lacrimal sac. The puncta are the openings of the canaliculi.

Front 11

CANTHUS

Back 11

The angle formed by the meeting of the upper and lower eyelids, specified as outer or temporal, and inner or medial (nasal).

Front 12

CAPSULAR TENSION RING

Back 12

PMMA ring inserted into capsular bag to stabilize capsule to withstand the pressures of cataract surgery.

Front 13

CATARACT

Back 13

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.

Front 14

CHOROID

Back 14

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.

Front 15

CILIA

Back 15

Technical term for eyelashes.

Front 16

ABERRATION

Back 16

The failure of a refracting surface or lens to produce an exact point-to-point correspondence between an object and its image.

Front 17

ABLATION

Back 17

Removal of all or part of an object, usually from the surface inward.

Front 18

ACCOMMODATION

Back 18

Adjustment by the ye for seeing at different distances, accomplished by changing the shape of the crystalline lens through action of the ciliary muscle.

Front 19

ADNEXA

Back 19

The tissues and structures surrounding the eye: eyelids, orbit, extraocular muscles, and lacrimal system.

Front 20

AMBLYOPIA

Back 20

Decreased visual acuity without any apparent disease of the eye.

Front 21

AMETROPIA

Back 21

Any optical error of the ye that can be corrected by glasses or contact lenses. See refractive error.

Front 22

ANTERIOR CHAMBER

Back 22

The area between the inner-most layer of the cornea and the iris.

Front 23

ANTERIOR CHAMBER ANGLE

Back 23

The junction of the cornea and the iris.

Front 24

ANTERIOR SEGMENT

Back 24

Front portions of the eye including the cornea, the anterior chamber, the iris, and the crystalline lens.

Front 25

APHAKIA

Back 25

Absence of the crystalline lens of the eye, usually as a result of cataract surgery.

Front 26

AQUEOUS HUMOR

Back 26

Clear watery fluid, which fills the anterior chamber of the eye.

Front 27

ASTIGMATIC KERATOTOMY (AK)

Back 27

Surgical procedure where incisions are made in the cornea to correct astigmatism.

Front 28

ASTIGMATISM

Back 28

Distortions in the cornea, or sometimes the lens, that focus light rays at different lengths, making it difficult to focus at any distance well.

Front 29

AUTOMATED LAMELLAR KERATOPLASTY (ALK)

Back 29

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.

Front 30

AUTOREFRACTION

Back 30

An automated objective refraction that measures each eye individually without patient response or interation.

Front 31

CILIARY BODY

Back 31

Band-like structure of muscle and secretory tissue

Front 32

CILIARY MUSCLE

Back 32

Muscle fibers in the ciliary body

Front 33

CILIARY MUSCLE

Back 33

Muscle fibers in the ciliary body

Front 34

CILIARY PROCESSES

Back 34

Inner surface of the ciliary body that is arranged in folds, rows or ridges. This structure secretes the aqueous humor.

Front 35

COLLAGEN

Back 35

A protein found in connective tissues which is relative inelastic but has high tensile strength.

Front 36

COLLAGEN

Back 36

A protein found in connective tissues which is relative inelastic but has high tensile strength.

Front 37

COMPUTERIZED CORNEAL TOPOGRAPHY (CCT)

Back 37

Measurement to map exact areas and degree of corneal astigmatism.

Front 38

COLLAGEN

Back 38

A protein found in connective tissues which is relative inelastic but has high tensile strength.

Front 39

COMPUTERIZED CORNEAL TOPOGRAPHY (CCT)

Back 39

Measurement to map exact areas and degree of corneal astigmatism.

Front 40

CONCAVE LENS

Back 40

A lens having a surface that is rounded inward, to produce focal power that diverges parallel rays of light. Also called diverging, myopic, or minus lens, denoted by the minus sign.

Front 41

COLLAGEN

Back 41

A protein found in connective tissues which is relative inelastic but has high tensile strength.

Front 42

COMPUTERIZED CORNEAL TOPOGRAPHY (CCT)

Back 42

Measurement to map exact areas and degree of corneal astigmatism.

Front 43

CONCAVE LENS

Back 43

A lens having a surface that is rounded inward, to produce focal power that diverges parallel rays of light. Also called diverging, myopic, or minus lens, denoted by the minus sign.

Front 44

CONE

Back 44

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.

Front 45

CONGENITAL

Back 45

Present at birth

Front 46

CONGENITAL

Back 46

Present at birth

Front 47

CONJUNCTIVA

Back 47

Thin, translucent layers of mucous membrane, which lines the eyelids and covers the front part of the eyeball, excluding the cornea.

Front 48

CONGENITAL

Back 48

Present at birth

Front 49

CONJUNCTIVA

Back 49

Thin, translucent layers of mucous membrane, which lines the eyelids and covers the front part of the eyeball, excluding the cornea.

Front 50

CONJUNCTIVITIS

Back 50

Inflammation of the conjunctiva.

Front 51

CONTACT LENS

Back 51

A lens constructed to fit directly in the eyeball.

Front 52

CONTACT LENS

Back 52

A lens constructed to fit directly in the eyeball.

Front 53

CONTRAST SENSITIVITY

Back 53

A measurement, which determines the ability of the observer to see a wide range of everyday objects under normal and reduced illumination conditions.

Front 54

CONTACT LENS

Back 54

A lens constructed to fit directly in the eyeball.

Front 55

CONTRAST SENSITIVITY

Back 55

A measurement, which determines the ability of the observer to see a wide range of everyday objects under normal and reduced illumination conditions.

Front 56

CONVERGENCE

Back 56

The process in which the visual axes of the two eyes are directed toward the same near point, with the result that the eyes are turned inward.

Front 57

CONTACT LENS

Back 57

A lens constructed to fit directly in the eyeball.

Front 58

CONTRAST SENSITIVITY

Back 58

A measurement, which determines the ability of the observer to see a wide range of everyday objects under normal and reduced illumination conditions.

Front 59

CONVERGENCE

Back 59

The process in which the visual axes of the two eyes are directed toward the same near point, with the result that the eyes are turned inward.

Front 60

CONVEX LENS

Back 60

A lens having a surface that Is curved outward to produce focal power that converges parallel Rays of light to s focus. Also called converging, hyperopic, or plus lens, denoted by the plus sign.

Front 61

CORNEA

Back 61

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 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 layer provide strength to the eye.

Front 62

CRYSTALLINE LENS

Back 62

A transparent lens suspended inside the eye immediately behind the iris, which brings rays of light to a focus on the retina.

Front 63

CRYSTALLINE LENS

Back 63

A transparent lens suspended inside the eye immediately behind the iris, which brings rays of light to a focus on the retina.

Front 64

CYCLOPLEGIC

Back 64

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.

Front 65

CRYSTALLINE LENS

Back 65

A transparent lens suspended inside the eye immediately behind the iris, which brings rays of light to a focus on the retina.

Front 66

CYCLOPLEGIC

Back 66

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.

Front 67

CYCLOPLEGIC REFRACTION

Back 67

A subjective refraction performed after instillation of cycloplegic drops. The cycloplegic drops temporarily prevent the muscular accommodation of the eye and permit a more objective evaluation of the refractive error of the eye.

Front 68

CRYSTALLINE LENS

Back 68

A transparent lens suspended inside the eye immediately behind the iris, which brings rays of light to a focus on the retina.

Front 69

CYCLOPLEGIC

Back 69

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.

Front 70

CYCLOPLEGIC REFRACTION

Back 70

A subjective refraction performed after instillation of cycloplegic drops. The cycloplegic drops temporarily prevent the muscular accommodation of the eye and permit a more objective evaluation of the refractive error of the eye.

Front 71

CYLINDRICAL LENS

Back 71

See toric lens.

Front 72

CRYSTALLINE LENS

Back 72

A transparent lens suspended inside the eye immediately behind the iris, which brings rays of light to a focus on the retina.

Front 73

CYCLOPLEGIC

Back 73

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.

Front 74

CYCLOPLEGIC REFRACTION

Back 74

A subjective refraction performed after instillation of cycloplegic drops. The cycloplegic drops temporarily prevent the muscular accommodation of the eye and permit a more objective evaluation of the refractive error of the eye.

Front 75

CYLINDRICAL LENS

Back 75

See toric lens.

Front 76

DEPTH PERCEPTION

Back 76

The ability to perceive the relative position of objects in space. See stereoscopic vision.

Front 77

CRYSTALLINE LENS

Back 77

A transparent lens suspended inside the eye immediately behind the iris, which brings rays of light to a focus on the retina.

Front 78

CYCLOPLEGIC

Back 78

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.

Front 79

CYCLOPLEGIC REFRACTION

Back 79

A subjective refraction performed after instillation of cycloplegic drops. The cycloplegic drops temporarily prevent the muscular accommodation of the eye and permit a more objective evaluation of the refractive error of the eye.

Front 80

CYLINDRICAL LENS

Back 80

See toric lens.

Front 81

DEPTH PERCEPTION

Back 81

The ability to perceive the relative position of objects in space. See stereoscopic vision.

Front 82

DILATE

Back 82

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

Front 83

DIOPTER

Back 83

A unit of measurement of strength or refractive power of lenses. Can also refer to the relative curvature of a lens surface.

Front 84

DIOPTER

Back 84

A unit of measurement of strength or refractive power of lenses. Can also refer to the relative curvature of a lens surface.

Front 85

EMMETROPIA

Back 85

The focal condition of the normal eye in which there is no refractive error.

Front 86

ENDOCYCLOPHOTOCOAGULATION (ECP)

Back 86

A laser attached to a camera used to ablate ciliary processes to reduce pressure inside the eye by decreasing aqueous production.

Front 87

EPITHELIUM

Back 87

A clear outer outer protective coating that covers the cornea, conjunctiva, and inner eyelid.

Front 88

ESOPHORIA

Back 88

A tendency of an eye to turn inward when covered.

Front 89

ESOTROPIA

Back 89

A condition in which one or both eyes turn too far inward, sometimes called convergent strabismus or crossed eyes.

Front 90

EXOPHORIA

Back 90

A tendency of an eye to turn outward when covered

Front 91

EXOPHTHALMOS

Back 91

An abnormal protrusion of the eyeball.

Front 92

FOGGING

Back 92

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.

Front 93

FORNIX

Back 93

The area where the palpebral and bulbar conjunctiva meet.

Front 94

FOVEA

Back 94

A small depression in the central retina at the back of the eye. The part of the macula adapted for most acute vision.

Front 95

FUNDUS

Back 95

The back of the eye, which can be seen with an opthalmoscope.

Front 96

FUSION

Back 96

The power of coordinating the images received by the two eyes into a single mental image.

Front 97

GAS PERMEABLE LENSES

Back 97

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.

Front 98

GLAUCOMA

Back 98

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.

Front 99

GLOBE

Back 99

More commonly known as the "eyeball"

Front 100

HALO

Back 100

A hazy ring around bright light, seen by some patients with refractive error.

Front 101

HAZE

Back 101

A clouding of vision sometimes reported following Laser-PRK. The condition usually corrects itself, after a period ranging from weeks to months.

Front 102

EXTROPIA

Back 102

A condition in which one or both eyes turn too far outward, sometimes called divergent strabismus.

Front 103

HYPERMETROPIA

Back 103

See farsightedness.

Front 104

HYPEROPIA

Back 104

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 non-existent or difficult. Distance vision may also be affected but it is usually clearer than the near vision when comparing the two.

Front 105

HYPERTROPIA

Back 105

A condition in which one eye deviates upward.

Front 106

INFERIOR OBLIQUE

Back 106

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.

Front 107

INFERIOR RECTUS

Back 107

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.

Front 108

INJECTION

Back 108

A term sometimes used to mean congestion of ciliary or conjunctival blood vessels; redness of the eye.

Front 109

INSTILLATION

Back 109

The process of placing drops in the surface of the eye though retraction of the lower lid.

Front 110

INTRAOCULAR LENS (IOL)

Back 110

An artificial lens put in the eye to replace the natural crystalline lens.

Front 111

INTRAOCULAR PRESSURE (IOP)

Back 111

The pressure of the contents of the eyeball. Increased IOP can be an indicator of an unwanted steroid response, which could lead to secondary glaucoma.

Front 112

IRIS

Back 112

The 'colored' portion of the eye. This muscle actually contains a contracting and expanding muscle within it. It regulates the amount of light that enters the eye and controls the size of the pupil with its movements.

Front 113

EXTRAOCULAR MUSCLES

Back 113

External muscles attached to the outside of the globe (eyeball) that are responsible for turning and rotating the eye. Each eye has four rectus and two oblique muscles.

Front 114

IRITIS

Back 114

Inflammation of the iris, a condition marked by pain, discomfort from light, contraction of pupil, and discoloration of iris.

Front 115

JAEGER TEST

Back 115

A test for near vision, lines of reading matter printed in a series of various sizes of type.

Front 116

KERSTITIS

Back 116

An inflammation of the cornea.

Front 117

KERATOCONUS

Back 117

A deformity in which the corneal curvature gets progressively steeper, making the cornea somewhat cone-shaped.

Front 118

KERATOMETER

Back 118

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.

Front 119

KERATOMETRY

Back 119

The measurement of the anterior curvatures of the cornea with a keratometer

Front 120

KERATOPLASTY

Back 120

The graft if a donor cornea to replace a damaged or diseased one.

Front 121

EYELIDS

Back 121

Moving folds of 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.

Front 122

FARSIGHTEDNESS

Back 122

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 vision is blurred at all distances.

Front 123

FIELD OF VISION

Back 123

The entire area, which can be seen without shifting the gaze.

Front 124

FLOATERS

Back 124

Small particles consisting of cells or fibrin, which move in the vitreous.

Front 125

FOCAL LENGTH

Back 125

The distance between a lens and he position where the lens brings parallel light rays to a focus.

Front 126

FOCAL POINT

Back 126

The position in the optical axis of a lens where parallel light rays are brought to a focus.

Front 127

FOCUS

Back 127

The point to which Rays are converged after passing through a lens.

Front 128

LACRIMAL APPARATUS

Back 128

The orbital structures that produce years and the ducts that drain the excess fluid from the front of the eye's into the nose.

Front 129

LACRIMAL GLAND

Back 129

Part of the lacrimal apparatus that produces tears. It is located in the lateral part of the upper lid just under the orbital rim.

Front 130

LACRIMAL SAC

Back 130

Collection chamber for teams after they have left the eye and traveled through the canaliculi.

Front 131

LASIK

Back 131

LASIK, or Laser In-Situ Keratomileusis, is a surgical procedure to reduce refractive errors that cause near-sightedness, far-sightedness, and astigmatism, conditions that are 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 cook ultraviolet laser applies pulses of energy in those inner layers of the cornea to slightly reshape and thin it. Because the cornea account for approximately 70% of the eye's total light bending ability, slight changes can dramatically reduce an individual's continued dependence on corrective lenses.

Front 132

LASER THERMAL KERATOTOMY (LTK)

Back 132

Applying finalized light energy to the peripheral cornea to correct hyperopia (far-sightedness).

Front 133

LATERAL CANTHUS

Back 133

The outer (temporal) side of th palpebral fissure.

Front 134

LATERAL RECTUS

Back 134

One of the six ocular muscles, which controls rotation around the vertical axis and moves the pupil away from the midline.

Front 135

LENS

Back 135

The lens is the clear structure located behind the pupil. It's primary function is to provide fine-tuning for focusing and reading. The lens performs this function by altering its shape. At about the age of 40 to 50, the lens becomes less flexible and presbyopia begins. At about the age of 60 to 70, the lens becomes cloudy and hard which prevents light from entering as well. This condition is called a cataract.

Front 136

LIMBUS

Back 136

The junction between the cornea and sclera.

Front 137

MACULA

Back 137

The small area of the central retina that surrounds the fovea which contains yellow pigment. The region provides the most distinct vision in the retina.

Front 138

MANIFEST REFRACTION

Back 138

A subjective refraction without use of cycloplegic drops.

Front 139

MANUAL REFRACTION

Back 139

A subjective refraction that measure each eye individually and together with patient interaction and response.

Front 140

MEDIAL CANTHUS

Back 140

The inner (nasal) side of the palpebral fissure.

Front 141

MEDIAL RECTUS

Back 141

One of the six muscles of the eye that controls rotation around the vertical axis and moves the pupil towards and midline.

Front 142

MICROKERATOME

Back 142

An incision device that removes precise amounts of surface of the cornea used for LASIK surgery

Front 143

MIOTIC

Back 143

A drug that causes the pupil to contract.

Front 144

MONOVISION

Back 144

A type of corrective procedure in which one eye is corrected for distance vision and the other is corrected for near vision.

Front 145

MYDRIATIC

Back 145

A drug that dilates the pupil.

Front 146

MYOPIA

Back 146

Nearsightedness. The eye is too long and the light rays are focusing too far in front of the retina. Nearsighted patients have very little trouble seeing up close but distance vision is blurry.

Front 147

NASOLACRIMAL DUCT

Back 147

The duct connecting the lacrimal sac and the nasal cavity. Tears pass through the nasolacrimal duct after leaving the lacrimal sac.

Front 148

NEAR POINT OF ACCOMMODATION

Back 148

The nearest point at which the eye can perceive an object distinctly. It varies according to the power of accommodation.

Front 149

NEARSIGHTEDNESS

Back 149

A refractive error in which, because the eyeball is too long in relation to its focusing power, the point of focus for rays of light from distant objects is in front of the retina.

Front 150

NEAR VISION

Back 150

The ability to perceive objects distinctly at normal reading distance, or about 14 to 16 inches from the eye

Front 151

NON-TORIC LENS

Back 151

A lens, which refracts rays of light equally in all meridians.

Front 152

NYSTAGMUS

Back 152

An involuntary rapid movement of the eyeball. May be lateral vertical or rotary.

Front 153

OBJECTIVE REFRACTION

Back 153

A refraction performed without patient interaction or response. Each eye is measured individually. Binocular visual acuity is not measured.

Front 154

OCULI UNITER (O.U.)

Back 154

Both Eyes

Front 155

OCULUS DEXTER (O.D)

Back 155

Right Eye

Front 156

OCULUS SINISTER (O.S.)

Back 156

Left Eye

Front 157

OPHTHALMOLOGIST

Back 157

An M.D. who specializes in diagnosis and treatment of defects and diseases of the eye, performing surgery when necessary or prescribing the other types of treatment.

Front 158

OPHTHALMOSCOPE

Back 158

An instrument used in examining the interior of the eye, especially the fundus.

Front 159

OPTIC ATROPHY

Back 159

Degeneration of the nerve tissue, which carries messages from the retina to the brain

Front 160

OPTIC DISC

Back 160

Head of the optic nerve in the eyeball. There is a complete absence of rods and cones here, thus it i insensitive to light and referred to as the blind spot.

Front 161

OPTICIAN

Back 161

One who grinds lenses, fits them into frames, and adjusts the frames to the wearer.

Front 162

OPTIC NERVE

Back 162

The optic nerve serves to carry the nerve fibers of the retina to the brain. IF the optic nerves are damaged from trauma or disease them permanent loss of vision can occur.

Front 163

OPTIC NEURITIS

Back 163

Inflammation of the optic nerve.

Front 164

OPTOMETRIST

Back 164

A specialist in diagnosing and treating visual and optical disorders of the eye, prescribing lenses, vision training, and other treatment. The primary eye and vision care practitioner.

Front 165

ORBIT

Back 165

The bony cavity in the skull that houses the globe, the extra ocular muscles, the blood vessels, and the nerves.

Front 166

PACHYMETRY

Back 166

Ultrasound measurement of the corneal thickness

Front 167

PALPEBRAL CONJUNCTIVA

Back 167

The portion of the conjunctiva that covers the inner surface of the eyelids.

Front 168

PALPEBRAL FISSURE

Back 168

The opening between the upper and lower lids

Front 169

PATHOLOGIC

Back 169

Resulting from diseases of the structure and function of the body

Front 170

PERIPHERAL VISION

Back 170

The ability to perceive the presence, motion or color of objects outside of the direct line of vision

Front 171

PHACOEMULSIFICATION

Back 171

Use of ultrasound or laser energy to break up a cataract for ease of removal

Front 172

PHAKIC LENS

Back 172

The natural lens

Front 173

PHORIA

Back 173

A latent deviation in which an eye has a tendency to turn from the normal position for binocular vision when covered. See Hyperphoria, Esophoria, Exophoria

Front 174

PHOTOPHOBIA

Back 174

Abnormal sensitivity to and discomfort from light

Front 175

PHOTOREFRACTIVE KERATECTOMY (PRK)

Back 175

A procedure to correct refractive error by ablating the surface of the central area of the cornea using an excimer laser. The laser beam ablation pattern is shaped to create the necessary corrective refraction. At Beacon Eye Institute, referred to as Laser-PRK {bmct bmps\tradmark.bmp}

Front 176

PHOTOTHERAPEUTIC KERATECTOMY (PTK)

Back 176

A procedure to treat pathologic conditions of the surface of the cornea using an excimer laser. The laser beam ablation pattern is flat to create a smoothing of the corneal surface.

Front 177

POSTERIOR CHAMBER

Back 177

The narrow space between the back of the iris and the front surface of the crystalline lens, bounded by the ciliary body.

Front 178

POSTERIOR SEGMENT

Back 178

All parts of the eye behind the crystalline lens; the vitreous and the retina.

Front 179

PRESBYOPIA

Back 179

The age-related inability of the crystalline lens to change or accommodate to focus on near object (normally occurs in individuals over age 40). Patients require a prescription to see tasks clearly up close.

Front 180

PSEUDOPHAKIC LENS

Back 180

A surgically implanted lens.

Front 181

PTERYGIUM

Back 181

A triangular fold of growing membrane, which may extend toward the cornea from the sclera

Front 182

PTOSIS

Back 182

A paralytic drooping of the upper eyelid

Front 183

PUNCTUM (PUNCTA)

Back 183

Tiny openings on the nasal side of the upper and lower lids through which excess tears pass when leaving the eye.

Front 184

PUPIL

Back 184

The pupil is the 'black circle' that you see in the center of a persons eye. The primary function of the pupil is to control the amount of the light entering the eye. When you are in a bright environment, the pupil becomes smaller to allow less light through. When it is dark the pupil expands to allow more light to reach the black of the eye.

Front 185

RADIAL KERATOTOMY (RK)

Back 185

A surgical procedure in which radial incisions are made in the peripheral cornea to flatten the central portion of the cornea and correct myopic refractive errors.

Front 186

REFRACTION

Back 186

In optics, the bending of light rays as they travel from one medium to another. Also, a test to determine the refractive error of an eye and the best corrective lenses to be prescribed.

Front 187

REFRACTIVE ERROR

Back 187

A defect in the eye that prevents light rays from being brought to a single focus exactly on the retina

Front 188

RETINA

Back 188

Inner-back surface of the eye. The retina contains light-sensitive cells that convert light to electric impulses that are carried to the brain

Front 189

RETINAL DETACHMENT

Back 189

A separation of the retina from the choroid

Front 190

RETINOSCOPE

Back 190

A hand-held instrument for determining the refractive state of the eye. It throws light from a moving mirror onto the retina, creating a movement of lights and shadows across the pupil

Front 191

ROD

Back 191

One of the two types of light-sensitive cells in the eye. Rod cells are responsible for vision in poor light and, apart from the central region and the blind spot, are found throughout the retina

Front 192

SCLERA

Back 192

White tissue (the white part of the eye) that forms the main structural component of the globe (eyeball). The scleral tissue is continuous from the cornea on the front of the eye to the optic nerve sheath in the back of the eye.

Front 193

SCLERITIS

Back 193

Inflammation of the sclera

Front 194

SEBACEOUS GLAND

Back 194

A gland that provides fatty lubrication to surrounding areas

Front 195

SLIT LAMP

Back 195

A corneal microscope, which provides a narrow beam of strong light, for examination of the front portions or the eye

Front 196

SNELLEN CHART

Back 196

Used for testing central visual acuity. It consists of lines of letters, numbers or symbols in graded sizes drawn to Snellen measurements. Each size is labeled with the distance at which it can be read by normal eye. Most often used for testing vision at 20 feet

Front 197

SOFT CONTACT LENS

Back 197

A contact lens made of soft plastic, which contains water and allows for oxygen transmission. Soft lenses are characterized by comfort and ease of adaptation. A soft contact lens is used to protect the cornea following Laser-PRK, aiding the healing process of the epithelium by reducing septic exposure.

Front 198

SPHERICAL LENS

Back 198

See Non-toric lens

Front 199

STEREOSCOPIC VISION

Back 199

The ability to use both eyes together to perceive the relative solidity and depth of objects in space

Front 200

STRABISMUS

Back 200

Sometimes called squint, and failure of the two eyes simultaneously to direct their gaze at the same object because of muscle imbalance. See Tropia, Esotropia, Exotropia

Front 201

STYE

Back 201

Acute inflammation of sebaceous gland in the margin of the eyelid, due to infection and usually resulting in the formation of pus

Front 202

SUBJECTIVE REFRACTION

Back 202

A refraction where patient response to alternative corrections is performed. It includes measurement of each eye individually and both eyes together

Front 203

SUPERIOR OBLIQUE

Back 203

One of the six muscles of the eye that allows rotation around all three axes and moves the pupil down and away from the midline and the top of the pupil towards the nose

Front 204

SUPERIOR RECTUS

Back 204

One of the six muscles of the eye that allows rotation around all threes axes and moves the pupil up and towards the midline and the top of the pupil towards the nose

Front 205

TONOMETER

Back 205

An instrument for measuring pressure inside the eye

Front 206

TORIC LENS

Back 206

A lens, which has differing radii of curvature in different meridians, which causes the refractive power to vary in the different meridians. Used in the correction of astigmatism

Front 207

TRABECULAR MESHWORK

Back 207

Spongy structure that filters the aqueous and controls its rate of flow out of the eye

Front 208

TROPIA

Back 208

A deviation of the eyes from they normal straight alignment

Front 209

UNCORRECTED VISUAL ACUITY (UCVA)

Back 209

The vision the patient has when they are not using any prescription to help them out. Also known as 'naked vision'

Front 210

UNILATERAL

Back 210

Relating to or affecting only one eye or one eye at a time

Front 211

UVEAL TRACT (UVEA)

Back 211

Collective name for the iris, ciliary body, and choroid

Front 212

VISION

Back 212

Sight, the faculty of seeing

Front 213

VISUAL ACUITY

Back 213

Ability of the eye to perceive the shape of objects in the direct line of vision, usually measured in terms of a Snellen fraction, such as 20/20

Front 214

VISUAL CORTEX

Back 214

The area of the brain that receives visual information

Front 215

VITREOUS

Back 215

The gleatinous, transplant, colorless substance filling the spa in the eyeball between the crystalline lens and the retina

Front 216

YAG PERIPHERAL IRODOTOMY

Back 216

Use of a laser to put holds in the iris to help relieve pressure by allowing aqueous outflow

Front 217

YAG POSTERIOR CAPSULOTOMY

Back 217

Use of a laser to put holes in the posterior chamber that has become opaque

Front 218

ZONULES

Back 218

Transparent fibers that radiate from the crystalline lens and attach to the ciliary body