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Clinical study
FEMTO LDV Z8
Cataract
IOP using liquid interface
following lens fragmentation
and capsulotomy1
baseline were found to be 12.3 ± 3.71 mmHg and following suction 42.5 ± 6.52 mmHg in a cohort of healthy individuals undergoing routine femtosecond laser cataract with
the FEMTO LDV Z8 (n = 10). This represented a mean escalation in IOP of 30.20 ± 7.50 mmHg (range 19.0–41.0
mmHg).
Background
200
IOP mmHg
Femtosecond laser assisted cataract surgery (FLACS) with
lens implantation offers potential advantages over conventional surgery including a controlled, precise means of creating a capsulotomy in order to remove the lens material
and a reduction in power needed to complete phacoemulsification following femtosecond laser lens fragmentation.
Femtosecond lasers rely on the use of a docking system
in order to stabilize the eye and target the laser energy but
inherently generate an increase in intra-ocular pressure
(IOP) that in turn can potentially lead to optic neuropathy.
The aim of this study was to determine the effect of the
Ziemer FEMTO LDV Z8 Femtosecond liquid patient interface laser platform on IOP during lens fragmentation and
capsulotomy.
100
0
0
50
100
150
200
Time (s)
Fig. 1. Representative plot demonstrating the difference between
peak and plateau IOP with suction on the FEMTO LDV Z8 at -10˚ arm
angulation.
Porcine eyes were recovered and used within six hours of
retrieval. Eyes were mounted on a pressurized stand and
a 30-gauge cannula connected to an IOP catheter transducer which was inserted into the anterior chamber, posterior to the limbus. Each cataract procedure was carried
out with standard clinical settings for lens fragmentation
and capsulotomy on the Ziemer FEMTO LDV Z8.
Patients undergoing routine femtosecond cataract surgery
with the Ziemer FEMTO LDV Z8 system at the Oftalmosalud Instituto de Ojos (LI) had tonometry performed from
the central cornea at the pre-docking (analogous to pre-cannulation in the porcine study), suction application and post
laser stages of surgery (analogous to post-cannulation). Patients had a median age of 73.2 years [range 69–77], and
did not have glaucoma or other co-morbid pathology prior
to surgery.
Results
The effects of angulation on IOP in porcine eye: we investigated the effect of altering the weighted hand piece on
IOP. It should be noted here that the moveable arm on the
LDV Z8 platform has a counter-weight so as to minimize
the effect of the hand piece weight. At an angulation close
to zero degrees, the hand piece was measured at 310 g.
By reducing the angulation to -10°, the weight was reduced
to 110 g due to the cantilever effect of the counterweight
on the laser arm. In turn this resulted in a laser IOP of 36.4
± 7.7 mmHg. In human subjects: IOP measurements at
Ziemer Ophthalmic Systems AG, CH-2562 Port, Switzerland
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www.femtoldv.com
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The FEMTO LDV Z8 FLACS system offers a flat applanation system like the Z6 for cornea and a liquid patient interface for cataract surgery. The latter is designed to minimize IOP rise during surgery, avoid posterior corneal folds
and relies on a vacuum, fluid filled, docking system via a
suction ring by negating compression. Existing literature
measures pressure rises following the suction process
only which range from 36 to 80 mmHg depending on the
FLACS system (LensEx, Catalys, Victus) but not during the
docking of the laser as in this study, which will invariably
be higher. By adjusting angulation of the arm piece by -10˚
the IOP rise from the FEMTO LDV negates the weight of
the laser head. In conclusion, the FEMTO LDV Z8 with the
liquid interface offers a safe cataract procedure with a minimal intra-op rise in IOP.
References:
1 G
. P. Williams, H. P. Ang, B. L. George, Y. C. Liu, G. Peh, L. Izquierdo, D. T. Tan & J. S. Mehta. Comparison of intra-ocular pressure changes with liquid or flat applanation interfaces in a femtosecond laser platform. Sci Rep. 2015 Oct 6;5:14742.
[email protected]
The FEMTO LDV Z8 is CE marked and FDA cleared. For some countries, availability may be restricted
due to regulatory requirements; please contact Ziemer for details.
Conclusions
Methods