JUNE 2003 CATARACT & REFRACTIVE SURGERY TODAY Page 1
Improve Visual Performance?
the results obtained with three IOLs.
ROBERT M. KERSHNER, MD, FACS
2002, the FDA approved the Tecnis Z-9000 lens
Inc., New York, NY), which features an anterior,
prolate, aspheric surface. The aim of
IOL’s design is to restore the balance between
positive spherical aberration of the cornea and the
spherical aberration of the youthful crystalline
that is lost upon the development of a cataract. At
ASCRS annual meeting in San Francisco in April
I presented the results of my study to determine
the the aspheric optic of the Tecnis lens can
retinal image contrast and functional visual
the prospective study, 221 eyes of 156 patients
randomized to receive either the STAAR AA4207-
Silicone IOL (STAAR Surgical Company, Monrovia,
an Alcon SA60AT acrylic IOL (Alcon Laboratories,
Fort Worth, TX), or a three-piece Tecnis IOL. I performed
of the lens extractions and IOL implantations.
and I collected data while blinded as to IOL
and we followed subjects for 6 months. We
patients’ visual acuity preoperatively and at
day, 1 week, 3 weeks, 1 month, 3 months, and 6
postoperatively. We performed fundus photography
functional acuity contrast testing under photopic
mesopic conditions preoperatively and at
months postoperatively. I analyzed the photographs via
Photoshop 7.0 image software (Adobe Systems
San Jose, CA) using the L*a*b color model,2
international standard for color measurement de-signed
be consistent no matter which device is used to
surgical or postoperative complications occurred
the course of this study. Thirty-one patients (7%)
a rise in postoperative IOP (>24 mm Hg)
was unassociated with lens style. The increase in
resolved with the release of aqueous and the
of one drop of 0.5% Timolol (Merck and Co.,
West Point, PA) to achieve IOPs below 18 mm Hg.
YAG capsulotomy rate at 6 months was 0.9% for the
group and 0% for the aspheric and acrylic
found no statistically significant difference between
groups in pre- and postoperative spherical, astigmatic
error or BCVA. Patients who received
aspheric IOL, however, achieved the best UCVA during
first postoperative month. Under photopic conditions,
demonstrated a 38% to 47% increase in
sensitivity, whereas I found little difference in
sensitivity under these lighting conditions between
preoperative cataract, silicone, and acrylic IOL
The aspheric IOL also performed best under
conditions (an improvement of 9% to 100% vs
to 50% in the acrylic group and 0% in the silicone
(Figure 1). Subjects who received the spherical
IOL experienced no increase in contrast sensitivity
compared with preoperative cataract levels. My
analysis of retinal imaging showed an increase in
luminance levels in the aspheric group, as well
in image contrast, when compared with the preoperative
silicone, and acrylic groups (Figure 2).
the 1-month visit, the UCVA of subjects who
acrylic IOLs matched that of those who received
aspheric IOL. A statistically significant difference
UCVA continued after the 3- to 6-month visits,
between the aspheric group (20/25 ±2) and
silicone (20/36 ±1) and acrylic (20/30 ±1) groups
at 6 months). This difference could not be explained
the basis of pre-existing or postoperative refractive error.
three IOLs improved patients’ UCVA after cataract
but the greatest improvement occurred in the
group during the first month. Patients who received
silicone IOL did not demonstrate improved
testing despite an improvement in visual acuity.
acrylic IOL improved patients’ contrast testing under
lighting levels when compared with preoperative
but the increased values were significantly less
those experienced by subjects who received aspheric
Although the clarity of the retinal imaging improved
all subject groups when compared with the
images, the retinal image contrast markedly
in the patients who received aspheric IOLs as
with those who received either silicone and
IOLs (Figure 3).
data demonstrate that implanting the aspheric
significantly enhances patients’ objective retinal
contrast and functional visual performance. This
technology may represent a new standard in IOL
Robert M. Kershner, MD, FACS, is Director of the Eye
Laser Center in Tucson, Arizona, and Clinical Professor
Ophthalmology at the Moran Eye Center, University of
Utah School of Medicine, Salt Lake City. He has no
or financial interest in the products described herein
Dr. Kershner may be reached at (520) 797-2020;
Kershner RM. A prospective evaluation of aspheric (Tecnis), silicone, and
acrylic IOLs on
image contrast and functional visual performance. J Cataract Refract Surg.
Adobe Systems Incorporated. Adobe Photoshop Users Manual. San Jose, CA;
1. Functional acuity contrast testing compares the
silicone, and acrylic IOLs.
2. The author analyzed retinal image contrast with pre-operative
and postoperative (right) fundus photography.
the marked improvement in image quality and contrast.
3. Threshold luminance displays the difference between
lightest edge (bottom of graph) and the darkest
(top of graph) for the pooled image data of each subject
Note that the widest range of contrast data for the
images was taken through the aspheric IOLs.
4. The TECNIS IOL in position.
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