PHAKIC FUTURE - LaserMed

OPHTHALMOLOGY WORLD REPORT DECEMBER 2007 SUPPLEMENT
Late-breaking randomized trial
Further support for
Toric ICL over corneal ablation
By Larry Schuster
Reviewed by Dr. Donald R. Sanders, MD, PhD
In a prospective, randomized study comparing the Visian
Toric Implantable Collamer Lens (Toric ICL) and photorefractive
keratectomy (PRK) in the correction of moderate to high
myopic astigmatism, researchers found the Toric ICL performed
better than the PRK in all key measures.
The superior outcomes of the Toric ICL were evident in
uncorrected visual acuity, refractive predictability, refractive
stability, change in best spectacle-corrected visual acuity,
change in contrast acuity, and glare symptoms. In addition,
dry eye complaints were lower with the Toric ICL procedure.
First author Steven Schallhorn, MD, Department of Ophthalmology,
Navy Medical Center San Diego, San Diego, Calif.,
and colleagues said the study provided further evidence that
the Toric ICL is a viable alternative to existing refractive
surgical treatments.
Figure 1
Figure 2
“A number of other clinical trials have compared outcomes
between the Visian ICL and LASIK or PRK, the researchers
wrote in their paper, published in the Nov. 23 issue of the
Journal of Refractive Surgery (J Refract Surg. 2007;23:853-
867). “All showed superior results of the ICL for various
refractive ranges. The outcomes of this comparison of PRK
and the Toric ICL support these findings and demonstrate that
in this study, Toric ICL correction results in a more effective
procedure than PRK surgery.”
They further note, “The dramatic improvement in outcome of
the ICL over LASIK or PRK is not unexpected as it is more
accurate to manufacture the exact correction required in a
HEMA material than to ablate the correction onto corneal
tissue, which is then subject to tissue healing.”
Completed at the Naval Medical Center San Diego, USA, the
study compared the clinical outcomes of PRK to the unapproved
toric phakic IOL for the correction of moderate to high
myopic astigmatism.
It involved 43 eyes implanted with the Toric ICL (20 bilateral
cases) and 45 eyes receiving PRK with mitomycin C (22
bilateral cases) with moderate to high myopia ( 6.00 to 20.00
diopters [D] sphere) measured at the spectacle plane and 1.00
to 4.00 D of astigmatism. Patients were followed for 1 year.
Patients had to be between the ages of 21 and 45 years, have a
stable refraction for the last 12 months as documented by previous
clinical records, and have a manifest refraction spherical
equivalent (MRSE) progression at a rate of 0.50D or less
during the year prior to the baseline examination.
Patients with a history of previous intraocular surgery, diabetes,
glaucoma, ocular hypertension, amblyopia, and/or any
serious ophthalmic or non-ophthalmic conditions that may
have precluded study completion were excluded.
Figure 3
in the PRK series in the early healing period (1 week; 19%
vs 0%, P=.006). Improvement in BSCVA (2 or more lines)
was statistically better in the Toric ICL group at 1-month
follow-up (0% vs 10%, P=.010), and the entire distribution of
change in BSCVA was statistically better with the Toric ICL
at all visits through 12 months (P .001).
The outcomes of this comparison of PRK
and the Toric ICL ... demonstrate that in this
study, Toric ICL correction results in a more
effective procedure than PRK surgery.
Improvement of 1 or more lines of BSCVA was better with
the Toric ICL series at all time periods studied (P .001).
Ninety-five percent of patients had an improvement of 1 or
more lines of BSCVA in the Toric ICL series at 12-month
follow-up compared to 39% in the PRK series.
(See Figure 2).
The proportion of cases with BSCVA of 20/12.5 or better
was significantly higher in the Toric ICL group at all postoperative
time periods (12 months; 71% vs 14%, P .001). Additionally,
the proportion of cases with BSCVA 20/16 or better
Figure 4 Figure 5
was also significantly higher in the Toric ICL group at all
postoperative periods. When using the entire distribution of
BSCVA values and not just the breakdown of 20/12.5, 20/16,
or 20/20, the Toric ICL had significantly better BSCVA at all
postoperative visits between 1 week and 12 months (P .001).
On adverse events, at 2 years postoperatively, the presence
of a grade 2 anterior subcapsular cataract was noted in one
(2.3%) Toric ICL patient. The patient had a preoperative
refraction of 6.50 2.25 @ 170°. One month postoperatively,
BSCVA was 20/25 (same as preoperatively) with a refraction
of 0.25 0.50 @ 019° and a clear crystalline lens.
The patient subsequently was lost to follow-up until 2 years
later. Best corrected vision at that time was 20/50.
On effectiveness outcomes, uncorrected visual acuity
improved dramatically in both groups. The proportion of
cases seeing 20/12.5 or better and 20/16 or better was significantly
higher in the Toric ICL group at all postoperative
time periods. Using the entire distribution of UCVA values
and not just 20/12.5, 20/16, or 20/20 cutoffs, the Toric ICL
was significantly better than PRK at all follow-up examinations
(P .001).
The Toric ICL showed a much larger percentage of eyes in
which the postoperative UCVA was better than the preoperative
BSCVA (61% vs 18%). Looking at the entire distribution
of the relationship between preoperative BSCVA to
the 12-month UCVA outcomes for the Toric ICL and PRK
procedures, the Toric ICL was statistically better (P .001).
(See Figure 3).
Predictability (attempted vs achieved correction) favored the
Toric ICL numerically at all postoperative visits ( 0.50D and
1.00D) and was statistically better at all time points except
12 months with regard to 0.50D (76% vs 57%, P=.101). The
scattergrams at 12 months postoperatively demonstrate more
variability in the PRK group and a tendency to overcorrect.
(See Figures 4 and 5).
RESULTS
On best spectacle-corrected visual acuity, the mean change
was significantly better with the Toric ICL than with PRK at
all time periods from 1 week through 12-month follow-up. At
all time periods, the Toric ICL group demonstrated significantly
more improvement in BSCVA than the PRK group
(P .001). (See Figure 1).
Loss of 2 or more lines of BSCVA was significantly higher