Refractive Lens Surgery

The leading haptic is placed into the capsule
filled with viscoelastic, and the trailing haptic
is placed with a second instrument as with
other plate-haptic IOLs.
Once the STIOL is placed fully within the
capsule, the STIOL is oriented into the desired
axis. Careful removal of viscoelastic
from between the posterior capsule and the
STIOL is important to help stabilize the implant
from early rotation, and this is done prior
to final orientation along the desired axis.
The axis is determined using the previously
placed limbal orientation marks or using
qualitative keratometry with projected light.
After final irrigation/aspiration of viscoelastic
and verification of a water-tight incision,
the STIOL orientation is again checked. Some
surgeons prefer to leave the eye slightly soft to
encourage early contact between the capsule
and the STIOL.
7.4.3 Postoperative Management
Management of eyes with the STIOL implanted
is similar to spherical IOL cases. If an offaxis
rotation of the STIOL is encountered, it is
best managed on an individual basis. As clinical
studies have shown, off-axis rotations of
the STIOL may occur in the very early postoperative
period, with later rotations rarely
observed. In most cases of mild rotation, the
UCVA remains excellent and no intervention
is needed. For larger rotations, the patient’s
tolerance of the malposition should be considered.
In refractive lens surgery, where patients
have an intense desire for excellent
UCVA, even moderate rotations may require
repositioning to the desired axis. The best
time for repositioning is 2–3 weeks after implantation.
If repositioned earlier, capsule fibrosis
may not be sufficient to prevent the
lens from returning to its original malposition.
After 3 weeks, the fibrosis of the capsule
intensifies, making repositioning more difficult.
After 2–3 months, the capsule assumes
the orientation of the long axis of the plate-
Chapter 7 Correction of Keratometric Astigmatism 65
haptic with significant fibrosis, and repositioning
to a new axis is difficult if not impossible.
Although some eyes may require
Nd:YAG capsulotomy for posterior capsule
opacification, there have been no reports of
STIOL malposition occurring after laser
treatment.
7.5 Improving Outcomes
with the STIOL:
Author’s Observations
and Recommendations
Experience with the STIOL over the past
6 years has provided several important insights
that have improved the author’s clinical
outcomes when using the STIOL for refractive
lens surgery. Discouraged by the occasional
off-axis rotations in the first year after
FDA approval, the author considered discontinuing
use of the STIOL at the same time that
data were becoming available that suggested
a novel method to promote stabilization of
the STIOL against rotation. As reported previously
[48], implanting the STIOL in a “reversed”
position, with the toric surface facing
the posterior capsule rather than the anterior
capsule, appeared to improve but not cure the
frequency of off-axis rotations. The rationale
for initially implanting the STIOL in this
manner, and the findings that resulted, will be
briefly reviewed here, with additional insights
to follow.
Why was the STIOL ever intentionally implanted
in the reversed position? After FDA
approval and initial enthusiasm for results
obtained with the STIOL, occasional patients
were encountered with “borderline” astigmatism.
For example, a patient may present with
1.2 D of corneal astigmatism, which is below
the manufactured suggested limit of 1.4 D.
The STIOL could “flip” the astigmatic axis in
such a patient. However, theoretical optics
calculate that the toric power of the STIOL
would be decreased by 8% if the optic was
reversed, as the toric (anterior) surface of the