Eye Care Glossary
A
Ablation zone: the area of tissue that is removed during laser surgery.
Accommodation: the ability of the eye to change its focus from distant objects to near objects.
AcrySof® ReSTOR® IOL: multifocal lens that can treat patients with both cataracts and presbyopia.
Acuity: clearness, or sharpness of vision.
Astigmatism: a distortion of the image on the retina caused by irregularities in the cornea or lens. In astigmatism, light is not brought into a sharp point of focus.
B
Bladeless LASIK: a laser device is used to create a corneal flap for lasik surgery.
C
Cataracts: clouding that develops in the lens of the eye, varying in degree from slight to complete opacity and obstructing the passage of light.
Cornea: the clear, front part of the eye. The cornea is the first part of the eye that bends (or refracts) the light and provides most of the focusing power.
Crystalens®: an artificial lens implant that, unlike a standard IOL, can treat both a person’s cataracts and presbyopia.
CustomVue™: custom-tailored laser vision correction procedure designed to correct the unique imperfections of your eyes.
Conductive keratoplasty: also known as CK, it is a type of refractive surgery that uses radio waves to adjust the contour of the cornea.
D
Diopter: the measurement of refractive error. A negative diopter value signifies an eye with myopia and a positive diopter value signifies an eye with hyperopia.
Dry Eye Syndrome: a common condition that occurs when the eyes do not produce enough tears to keep the eye moist and comfortable.
E
Endothelium: the layer of cells on the inside surface of the cornea.
Epithelium: the outermost layer of cells of the cornea and the eye’s first defense against infection.
Excimer laser: an ultraviolet laser used in refractive surgery to remove corneal tissue.
F
Farsightedness: the common term for hyperopia.
G
Ghost image: a fainter second image of the object you are viewing.
Glare: scatter from bright light that decreases vision making it difficult seeing in the presence of bright light.
Glaucoma: group of eye conditions that lead to damage to the optic nerve, the nerve that carries visual information from the eye to the brain.
H
Halos: are rings around lights due to optical imperfections in or in front of the eye.
Haze: corneal clouding that causes the sensation of looking through smoke or fog.
Hyperopia: the inability to see near objects as clearly as distant objects, and the need for accommodation to see distant objects clearly. Also known as farsightedness.
I
iFS Laser: laser technology that is a 100% blade-free approach to performing LASIK.
Intacs®: a reversible refractive surgery procedure that can be used to correct mild amounts of nearsightedness.
Intraocular lens: also known as IOLs, are lenses implanted in the eye, usually replacing the existing crystalline lens because it has been clouded over by a cataract.
Intraocular pressure: the fluid pressure inside the eye.
Iris: the colored ring of tissue suspended behind the cornea and immediately in front of the lens.
K
Keratectomy: the surgical removal of corneal tissue.
Keratotomy: a surgical incision of the cornea.
Keratitis: inflammation of the cornea.
Keratomileusis: lifting the front surface of the cornea in order to reshape it.
L
Laser: the acronym for light amplification by stimulated emission of radiation. A laser is an instrument that produces a powerful beam of light that can vaporize tissue.
LASIK: the acronym for “laser assisted in situ keratomileusis” which refers to creating a flap in the cornea with a microkeratome and using a laser to reshape the underlying cornea.
Lens: a part of the eye that provides focusing power. The lens is able to change shape allowing the eye to focus at different distances.
M
Microkeratome: a mechanical surgical device that is affixed to the eye by use of a vacuum ring. When secured, a very sharp blade cuts a layer of the cornea at a predetermined depth.
Monovision: the purposeful adjustment of one eye for near vision and the other eye for distance vision.
Myopia: the inability to see distant objects as clearly as near objects. Also known as nearsightedness.
N
Nearsightedness: the common term for myopia.
NearVision SM CK®: unique conductive keratoplasty vision correction treatment that reshapes the cornea using radiofrequency.
O
Ophthalmologist: a medical doctor specializing in the diagnosis and medical or surgical treatment of visual disorders and eye diseases.
Optician: an expert in the art and science of making and fitting glasses and may also dispense contact lenses.
Optomap™: a retinal exam that provides a panoramic view of the back of a person’s eye.
Optometrist: a primary eye care provider who diagnoses, manages, and treats disorders of the visual system and eye diseases.
P
Potential acuity meter: also known as PAM, a device that is designed to project an eye chart directly onto the retina, allowing the examiner to test visual acuity without interference of the cloudy lens.
PRK: the acronym for “photorefractive keratectomy” which is a procedure involving the removal of the surface layer of the cornea and the use of a computer controlled excimer laser to reshape the stroma.
Presbyopia: the inability to maintain a clear image as objects are moved closer. Presbyopia is due to reduced elasticity of the lens with increasing age.
Pupil: a hole in the center of the iris that changes size in response to changes in lighting. It gets larger in dim lighting conditions and gets smaller in brighter lighting conditions.
R
Radial Keratotomy: commonly referred to as RK; a surgical procedure designed to correct myopia (nearsightedness) by flattening the cornea using radial cuts.
Refraction: a test to determine the refractive power of the eye; also, the bending of light as it passes from one medium into another.
Retina: a layer of fine sensory tissue that lines the inside wall of the eye. The retina acts like the film in a camera to capture images, transforms the images into electrical signals, and sends the signals to the brain.
Rezoom™ Multifocal IOL: an advanced procedure used to treat cataracts and helps most people see without depending on glasses.
S
Sclera: the tough, white, outer layer of the eye that, along with the cornea, protects the eyeball.
Selective laser trabeculoplasty: also known as SLT, is one of newest advances in the surgical treatment of intraocular pressure in patients with open-angle glaucoma.
Stroma: the middle and thickest layer of tissue in the cornea.
V
Visual Acuity: the clearness of vision; the ability to distinguish details and shapes.
VISX Star S4 ActiveTrak™: excimer Laser System that incorporates variable beam technology with an active eye tracking system.
Vitreous Humor: the transparent, colorless mass of gel that lies behind the lens and in front of the retina and fills the globe of the eyeball.
W
Wavefront: a measure of the total refractive errors of the eye, including nearsightedness, farsightedness, astigmatism, and other refractive errors that cannot be corrected with glasses or contacts
