Because of the numerous refractive surgery
terms that are used almost exclusively in the successful understanding of
refractive disorders, first presenting a glossary of terms to assist the reader
is essential.
Glossary of terms
Ablation -
Removal. In excimer laser surgery, a frequency of energy causes corneal
molecules to detach from one another from their points of attachment.
AK - Abbreviation
for astigmatic keratotomy
ALK -
Abbreviation for automated lamellar keratectomy
ArF -
Abbreviation for argon fluoride
Astigmatic keratotomy
- Surgical procedure in which microscopic incisions are positioned in the
peripheral cornea to create a more spherical shape
Astigmatism - A
refractive condition where the surface of the cornea is not spherical. A
distorted image is formed because light images focus on 2 separate points in the
eye.
Automated lamellar keratoplasty
- An incisional refractive surgery method used in low-to-moderate myopia. An
automated microkeratome placed on the eye removes, in an oscillating shaving
motion, a thin layer of cornea that is microns thick. Subsequent removal of a
thinner underlying corneal stroma is performed with stitchless replacement of
the initial superficial cap.
Excimer -
Abbreviation for excited dimer
LASEK -
Abbreviation for laser epithelium keratomileusis
Laser -
Abbreviation for light amplification by the stimulated emission of radiation
Laser in situ keratomileusis
- A refractive laser procedure combining the use of ALK and photorefractive
keratectomy in reshaping the central cornea to treat refractive errors. An
automated microkeratome, similar to that used in ALK, is used to fashion a flap
with a hinge. Subsequent ablation is performed on the corneal stromal bed with
stitchless replacement of the corneal flap.
Laser epithelium keratomileusis
- A modification of the epithelial debridement performed in photorefractive
keratectomy. In this procedure, the epithelium is detached with the use of an
alcohol solution (usually 20%) to lyse DNA bonds (Cleave basement membrane) and
to soften the epithelium to facilitate rolling over into a flap. Ablation is
performed subsequently with replacement of the epithelial flap.
LASIK -
Abbreviation for laser in situ keratomileusis
Light amplification by stimulated emission
of radiation - Laser light is composed of one color
(wavelength) traveling in one direction, and each light wave is traveling in
step with the adjacent wave, making the laser light more powerful by a factor of
millions.
Oblate - Shape of
the cornea after conventional laser ablation profile where it is steeper in the
periphery
PARK -
Abbreviation for photoastigmatic refractive keratectomy
Pachymetry -
Optical or ultrasonic procedure to measure the corneal thickness
Photoastigmatic refractive keratectomy
- Although similar to photorefractive keratectomy, the ablation profile is
specific for astigmatism.
Photorefractive keratectomy
- Surgical procedure using an excimer laser to fashion the central cornea to
treat refractive errors
Prolate - Normal
corneal shape; steeper in the center
PRK -
Abbreviation for photorefractive keratectomy
Topography - Used
to measure the low or high areas of a plane
Wavefront -
Describes the surface that connects all the points on a propagating light wave
that are of equal phase
Wavelength - The
distance between the top of one wave and the top of the next wave. In the case
of an excimer laser, this is measured in nm (eg, argon fluoride has a wavelength
of 193 nm).
GLOSSARY information compiled by Dr.
Manolette Roque [ Resume
| Email ] and initially uploaded on
December 01, 2004.
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Last
updated on
September 14, 2007.
