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New IOL fixes suture-free in capsule-less eyes
Stefanie Petrou-Binder MD
A NEW sulcus-fixated, sutureless IOL appears to offer a promising
alternative for eyes lacking capsular support, report German researchers.
"Our first experiences with this device are encouraging. The
lens allowed stable fixation against dislocation and tilting without
the support of the capsule or transscleral sutures. This eliminated
the risk of complications associated with fixation sutures and two-point
IOL fixation, while providing an effective implantation technique
that was less traumatic," Oliver Schwenn MD told EuroTimes.
Dr Schwenn implanted the device (Binder IOL, IOLution) in three
aphakic eyes of two patients lacking capsular support. In these
first case studies, success followed initial failure.
The first case was a 35-year-old male patient with an aphakic left
eye resulting from a trauma sustained fifteen years prior to lens
implantation. He had remained untreated from the time of the eye
trauma. The investigators noted vitreous incarceration in the old
sclero-corneal incision at the base of the iris, peripheral anterior
synechiae, and iris trauma.
One week after IOL implantation, visual acuity was 20/20. Four months
post-operatively, however, one of the iris anchors subluxated from
its position (1.0 mm iridotomy diameter), and although the haptics
remained embedded in the sulcus and held the lens in position, it
eventually dislocated completely six months postoperatively and
was removed.
The surgeons addressed the initial problem by performing iridectomies
with 0.5 mm diameters in the following two cases. The second and
third implantations were free of complications and vision was 20/20
in the immediate post-op period. The iris anchors held firmly and
hindered the device from sliding backwards. One-year follow up showed
no sign of iris anchor dislocation or lens instability. The corneas
were clear and the endothelium unchanged.
Visual acuity remained 20/20 in both eyes and the fundus was normal.
Follow-up exams at three years after implantation revealed no changes
in the position of the IOLs. Close examination of the iridectomies
showed slight enlargement.
Simple technique
Dr Schwenn performed two preoperative basal iridotomies at 3 and
9 o'clock using an ND:YAG-laser that he placed at approximately
0.5 mm from the anterior chamber angle. The operative iridotomy
diameter was 0.5 mm. He then carried out an extensive anterior vitrectomy
through two corneal paracenteses at the 2 and 10 o'clock positions,
to avoid vitreous incarceration or prolapse.
The implantation technique itself essentially involves a conventional
sulcus-implantation, with the additional help of the two peripheral
iridotomies for anchor placement, and without additional sutures.
Dr Schwenn began by inserting the leading haptic through the 6 mm
limbal cut. While doing so, he folded the anchor of the leading
haptic under the optic to prevent it from getting caught at the
edge of the incision. He placed the leading haptic in the sulcus
at 6 o'clock with its anchor tentatively hooked onto the pupil.
The surgeon then placed the second haptic in the sulcus at 12 o'clock
with its anchor tentatively hooked onto the pupil at 9 o'clock.
He rotated the lens 90° clockwise. He completed the IOL implantation
by positioning the iris anchors in the iridotomies from behind the
iris, through the corneal paracenteses, using a special haptic-forceps.
He emphasised that the precise size and placement of the two basal
iridectomies and the careful buttoning-in of the two haptic-anchors
were essential, as the 1.0 mm iridectomy size may have accounted
for anchor subluxation in the first case along with the additional
disadvantage of the patient's iris pathology.
The smaller iridectomies performed in the latter two operations
held the haptic anchors in place. The anchors serve not only to
protect the lens from rotation and dislocation, but they also enable
the surgeon to know the exact position of the haptic region lying
in the sulcus.
Why a new IOL?
Helmut Binder MD, the IOL developer, told EuroTimes that small changes
in lens design can make a big difference. The nuances of this device
are simple and effective. The two IOL haptics are designed to run
along and become embedded within almost the entire length of the
ciliary sulcus, providing increased stability in all plains. The
haptics end in two peripheral iris anchors that 'button' onto the
iris surface through peripheral iridectomies to prevent backward
sliding.
IOL stability is provided by the intact capsule. When the posterior
capsule is lost, the lens design and the anatomic area of IOL fixation
take on a decisive role in lens stability and the risk of complications.
The problem is that not all IOLs made for eyes lacking capsular
support are suitable for all patients. At the same time, scleral,
iris, and anterior chamber angle fixation have potential disadvantages.
Sutured scleral fixation is associated with lens tilting and decentration
in a relatively high percentage of cases. This complication is due
chiefly to IOL fixation at two opposite points, which may allow
movement. Embedding the haptics along an extended length of the
sulcus provides a much larger contact surface and a better hold,
Dr Binder explained.
Other problems that are seen with scleral sutures include pupil
ovalisation, suture erosion, vitreous haemorrhage, and macular oedema,
both intra- and postoperatively.
Iris fixation using iris claw lenses has drawbacks that are seen
particularly in aphakic eyes, as the lack of compartmentalisation
allows greater movement of the iris-IOL diaphragm. Aside from being
somewhat difficult to perform, iris tissue may insufficiently incarcerate
in the lens claws, resulting in lens decentration and potentially
injuring the endothelium. Too much incarcerated pupil tissue, conversely,
may cause pupil ovalisation and iris atrophy. Visual impairments
such as glare and halos have also often been reported due to the
limited size of the optic.
Although anterior chamber lenses are very effective, they are not
suitable for all patients. Studies show that they can cause serious
complications of which endothelial cell loss, pupil ovalisation,
and secondary glaucoma are the most common.
The investigators believe that increased experience with this implantation
technique promises to improve the already good results. The procedure
is, in comparison to the sutured lens, less difficult, less traumatic,
and more precise regarding the positioning of the lens.
H Burkhard Dick, head of refractive surgery at Mainz University
Eye Clinic, believes that this lens shows great promise:
"With regard to surgery, a lens that requires no sutures means
no bleeding, less infections, and less trauma to the patient. In
terms of design, the long haptics would allow surgeons to have one
lens in stock that can fit well in both adult and child eyes, which
is quite practical. The iris anchors offer added practicality by
indicating the exact position of the lens, which you do not have
with other lens types. As tilting remains a problems with two-point
sutured lenses, the increased stability provided by this lens is
a great advantage," he said.
Dr Dick suggested that the device be investigated in a large multicentre
trial, to validate the results. As its fixation is very stable,
it could find application as a toric IOL as well. He said that many
manufacturers of toric lenses do not offer IOLs for aphakic eyes
without capsular support.
The research appeared in the May 2003 issue of Journal of Cataract
and Refractive Surgery.
Oliver
Schwenn MD
Augenklinik,
Bürgerhospital,
Frankfurt am Main, Germany
o.schwenn@buergerhospital-ffm.de
Helmut Binder MD
hbinder@t-online.de
H Burkhard Dick MD
Universitats-Augenklinik
Mainz, Germany
bdick@mail.uni-mainz.de
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