Glossary
A
Ablate: a term in surgery which means to remove.
Ablation zone: the area of tissue which is removed during laser surgery.
Accommodation: the ability of the eye to change its focus from distant objects to near objects.
Acuity: refers to the clearness or sharpness of vision.
Age Related Macular Degeneration: Destruction and loss of the photoreceptors in the macula region of the retina leading to decreased central vision and, in advanced cases, blindness.
Ametropia: Any imperfection in the refractive state of the eye such as hyperopia (farsighted, longsighted vision), myopia (nearsighted, short-sighted vision), or astigmatism (irregular cornea).
Astigmatism: a distortion of the image on the retina caused by irregularities in the cornea or lens.
C
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.
CustomVue procedure: A laser eye surgery procedure which involves anaesthetic drops being placed in the eyes and a flap created on the cornea. The procedure typically takes several seconds.
D
Diopter: the measurement of refractive error. A negative diopter value indicates an eye with myopia and positive diopter value indicates 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 inner layer of cells on the inside surface of the cornea.
Epithelium: the outermost layer of cells of the cornea and the eye's first defence against infection.
Excimer laser: an ultraviolet laser used in refractive surgery to remove corneal tissue.
F
Farsightedness: the common term for hyperopia which is the inability to see near objects as clearly as distant objects, and the need for accommodation to see distant objects clearly.
Flap & Zap: an American slang term for LASIK.
G
Ghost Image: a fainter second image of the object that is being viewed.
Glare: a scatter from bright light that decreases vision.
H
Halos: visual rings form that around lights due to optical imperfections in or in front of the eye.
Haze: corneal clouding that causes the impression 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.
I
In Situ: a Latin term meaning "in place" or not removed.
Inflammation: the body's reaction to trauma, infection, or a foreign substance which can result in pain, heat, redness, swelling, and/or loss of function.
Informed Consent Form: a document outlining the risks, benefits and alternatives to a procedure.
Intralase: the first blade-free laser technology for carrying out the first step of the LASIK procedure, the creation of the corneal flap.
Iris: the coloured ring of tissue suspended behind the cornea and immediately in front of the lens.
K
Keratectomy: the surgical removal of corneal tissue.
Keratitis: inflammation of the cornea.
Kerato: prefix indicating relationship to the cornea.
Keratoconus: a disorder characterised by an irregular corneal surface (cone-shaped) which results in blurred and distorted images.
Keratomileusis: the reshaping of the cornea through surgical incisions.
Keratotomy: a surgical incision (cut) of the cornea.
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 vaporise tissue.
Laser Eye Surgery: is a surgical procedure to reduce a person's dependancy on glasses or contact lenses.
LASEK: is a laser refractive procedure to correct nearsightedness, farsightedness and astigmatism.
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 some of the eye’s focusing power. The lens is able to change shape allowing the eye to focus at different distances.
M
Microkeratome: a 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. Prior to Intralase, this first step was done manually using a handheld device with an oscillating metal razor blade, called a microkeratome. While LASIK has proven to be a successful and relatively safe procedure, the majority of complications with LASIK arise from the use of the microkeratomes.
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.
N
Nearsightedness: the common term for myopia and refers to the inability to see distant objects as clearly as near objects.
O
Ophthalmologist: a medical doctor specialising in the diagnosis and medical or surgical treatment of visual disorders and eye disease.
Optician: an expert in the art and science of making and fitting glasses and may also dispense of contact lenses.
Optometrist: a primary eye care provider who diagnoses, manages, and treats eye diseases and disorders of the visual system.
Overcorrection: a complication of refractive surgery where the achieved amount of correction is more than desired.
P
Pentacam: A pentacam is a comprehensive eye scanner for the anterior eye segment. A pentacam is used to read corneal topography (corneal curvature) and to measure the corneal pachmetry (corneal thickness).
Presbyopia: the inability to maintain a clear focus on objects as they are moved closer. Presbyopia is due to reduced elasticity of the lens with increasing age.
PRK: the acronym for photorefractive keratectomy which is a procedure involving the removal of the surface layer of the cornea (epithelium) by gentle scraping and use of a computer-controlled excimer laser to reshape the stroma.
Pupil: a hole in the centre of the iris that changes size in response to changes in lighting. It increases in size in dim lighting conditions and decreases in brighter lighting conditions.
R
Radial Keratotomy: commonly referred to as RK, which is 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 which is the ability of the eye to bend light as it passes from one medium into the eye.
Refractive Errors: imperfections in the focusing power of the eye, for example, hyperopia, myopia, and astigmatism.
Refractive Power: the ability of an object, such as the eye, to bend light as it passes through it.
Retina: a layer of fine sensory tissue that lines the inside wall of the eye. The retina captures images which it then transforms into electrical signals and forwards to the brain.
S
Sclera: the tough, white, outer layer (coat) of the eyeball that, along with the cornea, protects the eyeball.
Snellen Visual Acuity Chart: A chart used to measure vision.
Stroma: the middle, thickest layer of tissue in the cornea.
U
Undercorrection: a complication of refractive surgery where the achieved amount of correction is less than desired.
V
Visual Acuity: the clearness of vision and the ability to distinguish details and shapes.
Vitreous Humor: the transparent, colourless mass of gel that lies behind the lens and in front of the retina to fill the centre 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.
Wavescan: is a measurement or map of the unique characteristics of your vision. With this map a surgeon can develop an individualised treatment plan to address your unique vision needs.