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Glossary of Lasik Laser Eye Surgery Related Terms
F
FACS
See Fellow of the
American College of Surgeons.
Farsightedness
Common term for hyperopia.
FDASee
Food and Drug Administration.
Flap & Zap
Slang term for
Lasik.
Femtosecond Laser
An infrared range laser that delivers pulses of energy within the
cornea, causing a small controlled explosion of gas that separates
the layers of the cornea. The femtosecond laser for ophthalmology use on
the eye is manufactured by Intralase
and is used to create a
Lasik flap in a procedure commonly called
All-Laser Lasik or "all laser Lasik".
Detailed Femtosecond All-Laser Lasik Information
Fluorescein Angiography
A test to examine blood vessels in the retina, choroid, and iris. A
special dye is injected into a vein in the arm and pictures are taken as
the dye passes through blood vessels in the eye.
Fluorescein Staining
A tiny amount of a fluorescein dye is placed in the tear film. The color
will make microscopic dots appear where the eye has become dry.
Excessive staining is an indication of dry eye.
Flying Spot
This is a method of applying excimer laser energy. Rather than applying
all excimer energy in a broadbeam across
the entire ablation area, or the energy in
variable spots sizes across the ablation area, a very small spot of
excimer energy is applied in rapid succession at different locations
across the ablation area.
Focusing Power Of The Eye
As light enters our eye, it must be brought to a focus on the retina in
order to perceive a clear image. About two thirds of the focusing power
of the eye comes from the cornea, the rest comes from the lens inside
the eye. As the light enters the eye, it is focused a fixed amount by
the cornea. As the light passes through the pupil, the lens then adjusts
the focus a variable amount with the exact amount of focusing power
applied dependent on the distance of the object being viewed. Objects at
near like a book or knitting require more power than distance objects
like movies or traffic signs.
Food and Drug Administration
The federal agency of the United States government responsible for the
evaluation and approval of medical devices. The FDA does not evaluate
surgical procedures that to not require a new medical device. Click for
Important FDA Links
or Click here to go to
Main FDA website.
Fovea
The central part of the macula that provides the sharpest vision.
Freeradical
Molecules that have been implicated as one causative factor in the
stimulation of abnormal cellular reproduction (cancer) and cellular
destruction (aging).
Fuch's Dystrophy
See Corneal
Endothelial Cell Dystrophy.
Functional Visual Disability
The degree to which a visual error interferes with a person's ability to
perform normal daily activities, such as reading, driving at night, or
performing hobbies.
Fundus
The interior lining of the eyeball, including the retina, optic disc,
and macula. This portion of the inner eye can be seen during an eye
examination by looking through the pupil.
G
GASH
See refractive surgery complications glare, arc, starburst, and halo.
Gaussian
This is a profile of how excimer energy is applied. Used primarily on
flying spot lasers, more energy is applied to the center of the spot
than at the outer edges.
Ghosting
This is a common term for double images. If you look at a clock and some
of the numbers have a lighter ghost image just off to the side, this is
ghosting.
Detailed Double Vision and Ghosting After Lasik Information
Glaucoma
A disease characterized by increased pressure within the eyeball. more
If not diagnosed and treated, glaucoma may lead to optic nerve damage,
loss of visual field, gradual vision impairment, and sometimes
blindness.
Gonioscopy
A diagnostic procedure using a mirror/lens device placed directly upon
the cornea that is used to view the drainage area through which aqueous
fluid exits the eyeball.
Gray Box Laser
Common term used for a laser imported from outside the United States.
This type of acquisition is not approved by the FDA.
Detailed Counterfeit Lasik Laser Information
H
Halos
A known complication of refractive
surgery that causes images from light sources to blur with circles
radiating out from the center. Halos also occur naturally without
refractive surgery.
Haptics
Extensions of plastic from the lens portion of an
intraocular lens (IOL) that position and center the IOL within the
eye.
Haze
An opacification or cloudiness of the normally clear cornea. Any build
up of inflammatory infiltrates (white blood cells), extra moisture, scar
tissue, or foreign substances (like drugs) can cause a clouding of the
cornea.
Health Maintenance Organization
A medical or vision insurance plan that requires beneficiaries to use
only the facilities and physicians who have contracted with the plan to
provide services to beneficiaries. Care provided to a patient by a
facility or physician that is not contracted by the Health Maintenance
Organization is not normally a covered benefit of the plan, except in
some emergency situations or with prior authorization from the plan.
Hemeralopia
Day blindness. Often caused by clouding or opacity of one or more of the
normally clear ocular tissues.
Higher Order Aberration
A common eye examination and refraction evaluates low order aberrations
(LOA). These are commonly called sphere
(myopia or
hyperopia) and cylinder (astigmatism).
Only a wavefront diagnosis is able
to measure high order
aberrations (HOA), which are beyond simple sphere and cylinder. HOA
are represented in mathematical calculations and are therefore infinite.
The more common of these mathematical calculations are
Zernike polynomials and have names like spherical aberration, coma,
trefoil, and secondary astigmatism. Ophthalmology only deals with about
the first eight levels of HOA as represented in Zernike.
HMO
See
Health Maintenance Organization.
HOA
See
Higher Order Aberration.
Humanitarian Device Exemption
A Humanitarian Device Exemption from the
Food and Drug Administration authorizes the use and marketing of a
device that is intended to benefit patients in the treatment of
conditions that affect fewer than 4,000 individuals.
Hyperopia
Also known as farsightedness or longsightedness. Hyperopia occurs when
the eyeball is too short from front to back, or the eye's focusing
mechanism is too weak, causing light rays to be focused behind, rather
than on, the retina. People with hyperopia have difficulty seeing
objects close up. This refractive abnormality requires a plus (positive
or convex) lens for correction. Hyperopia is significantly more
difficult to correct with
refractive surgery.
Detailed
Hyperopia (Farsighted/Longsighted) Lasik Vision Correction Information
Hypobaric
Environment with a decrease of atmospheric pressure, such as at high
altitude.
Hypoxia
A deficiency of oxygen supply to a tissue.
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Last updated
Friday, January 01, 2010
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