Glossary of Lasik Laser Eye Surgery Related Terms - M-O
Wrinkles in the Lasik flap. Detailed Lasik and Bladeless Lasik Flap Macro Striae (Wrinkles)
The small, sensitive area of the central retina;
provides vision for fine work and reading.
The collection of fluid in and under the macular portion of the retina causing
An examination of the eye to determine refractive error while the natural crystalline lens is able to accommodate.
Most older technology excimer laser machines employ different kinds of
masks to customize, refine, and smooth the corneal surface. Many machines
have an internal constricting diaphragm (like a camera f-stop mechanism) as
an internal mask. Variable rotation of the masks is used to deal with
See Medical Doctorate.
Nasal or towards the nose.
A certificate affirming that the holder has achieved the training
required to be a medical doctor through a school of medicine.
A shortened name for Aesculap-Meditec.
Large specialized sebaceous glands in the eyelid. There are about 50
glands on the upper lids and 25 glands on the lower lids. They create and
distribute an oily substance called lipids. Meibomian gland secretions help
keep the eye moist. When blinking, the upper lid comes down, presses on the
oil and pulls a sheet of oil upwards, coating the tear layer beneath to keep
it from evaporating.
Meibomian Gland Dysfunction
A dysfunction of the meibomian glands that provide an oily film over
natural tears to keep them from evaporating too quickly. Detailed
Meibomitis and Lasik Dry Eye Information
Mesopic Pupil Size
The size of a pupil under medium light conditions such as daylight or a well lit room.
Also called Bowman's Crinkles. Very
small wrinkles in the flap caused by Bowman's layer constricting. Detailed Lasik and
Bladeless Lasik Flap Micro Striae (Wrinkles)
A unit of length equal to one-millionth of a meter.
A surgical device for creating a flap of corneal tissue used in Lasik and some transplant techniques. There are two classes of
microkeratomes: mechanical and laser. Both are affixed to the eye by use of
a vacuum ring, flatten the cornea with a clear applanation plate, then cut
across the cornea under the plate.
microkeratome uses a very sharp and thin metal blade. The femtosecond laser
microkeratome uses amplified light energy to cause tiny bubbles to form at a
predetermined depth. Thousands of these bubbles next to each other create an
incision. See Bladeless Lasik.
Abnormally small size of eye.
A nanometer, or 10 to the -9 power meter. The term millimicron was used
Involving one eye. As example, monocular polyopia is when a person sees multiple images in one eye.
A technique to limit the effects of presbyopia by correcting one eye for near vision and the other for far
vision. Detailed Lasik Monovision Article
Named for engineer Charles R. Munnerlyn, Ph.D, who pioneered the
technology for vision correction based on the excimer laser. This is the
basic formula to calculate the amount of tissue that needs to be removed to
affect refractive change. Detailed Laser Tissue Removal Calculation Information
Also known as
nearsightedness or shortsightedness. Myopia occurs when the eyeball is too
long from front to back, or the eye's focusing mechanism is too strong,
causing light rays to be focused in front, rather than on, the retina. People with myopia have difficulty seeing objects far away. This refractive abnormality requires a minus (negative or concave) lens for
Abbreviation is nm. 10 to the -9 power meters. The term nanometer has
replaced the term millimicron that was used before 1967.
Toward the nose.
for Quality Assurance
An independent, non-profit organization that certifies credentials
verification organizations and accredits managed care organizations.
National Eye Institute
A division of the US federal government's National Institutes of Health.
Approximately three-fourths of US eye research funding originates at the
National Eye Institute.
Committee for Quality Assurance.
Near Point Of Accommodation
The closest point in front of the eyes that an object may be clearly
Near Point Of Convergence
The maximum extent the two eyes can be turned inward.
Common term for myopia.
Trade mark for the use of CK to restore near vision for individuals with presbyopia. The technique is similar to monovision. Detailed y CK Information
See National Eye Institute.
The formation of new blood vessels, often fragile and inappropriate for
the location. Long-term use of contact lenses can starve the cornea of oxygen, causing neovascularization as the body attempts to
provide oxygen through blood vessels.
Commonly known as cataracts. Nuclear sclerosis is an opacity or clouding
of the natural crystalline lens that may prevent a clear image from forming
on the retina. Cataracts occur naturally and can be induced by trauma. The
cataractous lens may require surgical removal if visual loss becomes
significant, with lost optical power replaced with an intraocular lens.
Ophthalmic equipment company.
Common term for nyctalopia.
Night blindness. Often caused by a deficiency of the retina due to a
lack of vitamin A.
An eye condition
characterized by rapid, jerky eye movements. Nystagmus
Elevated intraocular pressure.
The cause of ocular rosacea is not understood but its symptoms can leave
the eyes feeling irritated and "gritty". Patients may experience redness,
tearing or crusting on the lashes. See Ocular Rosacea Details
Off Label Use
A term used for procedures that are legal, but are not specifically
approved for a particular device or drug. An example is Lasik. The excimer laser is FDA approved for PRK,
but not for Lasik, which is a combination of ALK and PRK. The Lasik procedure comes under the definition of the
practice of medicine (also called scope of practice), so the FDA does not
necessarily need to approve the use of the excimer laser specifically for
Lasik. An easier example is the scalpel. The scalpel is not specifically
approved for all procedures that may require a scalpel, but if a medical
doctor determines the use of this FDA approved tool is appropriate, then it
is okay with the FDA. Some excimer lasers have received FDA approval
specifically for Lasik, but this is more for marketing purposes than to
accommodate any legal requirement.
Anything to do with the eye.
Ophthalmic Imaging Systems
Ophthalmic equipment company.
A medical doctor who specializes in the diagnosis and medical or
surgical treatment of eye diseases. To become an ophthalmologist one must
first obtain a medical degree (M.D. or D.O. in North America) and then
complete further specialty training. A medical degree typically takes 7 or 8
years university training and a specialist certification an extra 3 years in
the USA or 4 years in Canada. Specialist MD's are usually divided into
"medical" and "surgical" disciplines. Ophthalmology is technically a
"surgical" discipline. Some ophthalmologists chose not to perform surgery
and can be called "medical ophthalmologists". An ophthalmologist may also
prescribe eyeglasses and contact lenses. Visit ophthalmology, optometry, and opticianry, to compare the three
disciplines of eye care.
Examination of the internal structures of the eye using an illumination
and magnification system.
The white, cup-like area in the center of the optic disc.
The circular area (disc) where the optic
nerve connects to the retina. Also know as
the optic nerve head.
The optic nerve is a bundle of nerve fibers, about the diameter of
pencil, which passes through the back of the eyeball and connects to the
nerve fiber layer of the retina. It can be
observed directly with an instrument called an ophthalmoscope. The optic
nerve carries the visual messages from the photoreceptors of the retina to the brain.
Optical Ablation Zone
The area of the cornea where the excimer laser ablation fully corrects refractive error. See also transition zone.
The area of the eye through which light passes to the retina. To reach the retina light must pass through the cornea, aqueous humor, crystalline lens, and vitreous while
passing through the pupil. The optical ablation zone is the area where a laser has created full refractive error correction. See also Transition Zone.
An expert in the art and science of making and fitting glasses. The
optician may also dispense and/or fit contact lenses, depending on local
licensing practices. Visit ophthalmology, optometry, and opticianry, to compare the three
disciplines of eye care.
A doctor of optometry is a non-medical primary eye health care provider
who specializes in the examination, diagnosis, treatment, management, and
prevention of diseases and disorders of the visual system. Optometrists
today most often complete a bachelor of science degree (with very specific
requirements) followed by an optometry degree program that requires four to
eight years to complete. Patient contact begins in the second professional
year with the final year being a full 12-month internship. Many optometrists
include the provision of contact lens and spectacle devices as part of their
daily practice. The optometrist may also prescribe medications, depending on
local licensing practices.
Visit ophthalmology, optometry, and opticianry, to compare the three
disciplines of eye care.
A non-surgical procedure using contact lenses to alter the shape of the
cornea to effect a change in the refractive error.
Also know as the "globe", the structural area of the facial skeleton
into which the eye is set.
A known complication of refractive
surgery where the expected amount of correction is more than desired.
Overcorrection often occurs where healing regresses less vigorously than predicted. See Overcorrection Details
Looking For Best Lasik Surgeon?
If you are ready to choose a doctor to be evaluated for conventional
or custom wavefront Lasik, Bladeless Lasik, PRK, or any refractive surgery procedure, we recommend you consider a doctor who has been evaluated and certified by the USAEyes nonprofit organization.
Locate a USAEyes Evaluated & Certified Lasik Doctor.
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