Current
Opinion in Ophthalmology, v 13, 1 (February 2002).
"Clear
Lens Extraction with Intraocular Lens Implantation for the Correction of Refractive Error"
Robert
M. Kershner, M.D., F.A.C.S.
Director,
Eye Laser Center
Clinical
Professor of Ophthalmology, University of Utah School of Medicine, Moran Eye
Center, Salt Lake City, Utah
Ik
Ho Visiting Professor of Ophthalmology, Chinese University of Hong Kong, Hong
Kong, SAR, China
Eye
Laser Center
Suite
303
1925
West Orange Grove Road
Tucson,
Arizona USA 85704-1152
Phone: (520) 797-2020 Fax: (520) 797-2235
e-mail:
Kershner@EyeLaserCenter.com
web
site:
Introduction
Lens extraction with the implantation of an
intraocular lens is the most commonly performed refractive procedure in the
world today. Since the invention of the intraocular lens by the late Mr. Harold
Ridley of England in 1949, lens implantation has been the primary correction of
the most common refractive error, that occurs as a result of cataract
extraction, aphakia,. In 1995, I
published my results on the technique of clear corneal cataract surgery with
the simultaneous correction of myopia, hyperopia and astigmatism (1). Today,
cataract surgery is looked upon more often as a refractive procedure that is
used to treat a clouded crystalline lens and simultaneously improve preexisting
refractive error to optimize uncorrected visual acuity.
The increasing acceptance of refractive procedures
to eliminate or reduce the need for spectacle and contact lens correction for
ametropias first gained acceptance with the radial keratotomy technique of the
late S. N. Fyodorov of Moscow, Russia.
Then in the early 1990s, the development of the excimer laser, enabled
surgeons to correct a larger array of refractive errors. Utilized in combination with the automated
keratome to create a corneal flap under which is removed by the laser a small
layer of cornea, LASIK as it is called (laser-in-situ-keratomilleusis), has
gained in popularity over the past decade.
The difficulty of using a mechanical device to create a consistent
corneal flap, and the limitations of removing corneal tissue without
compromising the corneal integrity, has lead surgeons to embrace an intraocular
approach to the correction of high orders of refractive error. Much work has been undertaken on the use of
refractive implantable lenses either in
the anterior chamber, iris supported or in the posterior chamber to solve
refractive problems with an implantable device. This approach also has held promise for the correction of
presbyopia, the natural loss of accommodative ability that comes with age.
The application of laser technology or implantable
lenses has fallen short of expectations for that population of individuals who
have high degrees of refractive error.
In addition, individuals who have corneal abnormalities such as,
irregularity, keratoconus, corneal dystrophies or scars, may be ineligible for
corneal surgery. What do we offer those
in whom corneal alteration procedures cannot be pursued? For these individuals and for those for whom
the visual quality of an intraocular lens implant with the simultaneous
correction of refractive error, may prove superior, the choice of lens surgery
may be a more acceptable alternative.