Iol Calculation; References; Iol Constants; Iol Constants Derived Using Optical Measurements - Haag-Streit LENSTAR LS 900 Mode D'emploi

ent light when carrying out pupillometry. The LS 900
ambient light, so do not use pupillometry as the decisive factor when
considering keratorefractive surgery.
• The white-to-white distance reading is merely an indirect measure-
ment of the inner lateral dimensions of the anterior ocular section. It
therefore provides only approximate indications of the actual inner
lateral dimensions of the anterior ocular section and of the size of
the implant used.

. IOL calculation

The measurements taken with the LS 900
of every IOL calculation. The other important part is the IOL constant
used to calculate the power of an IOL to be implanted. Using the LS
900 , an optical non contact biometer, constants optimised for optical
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biometry should be used. Please contact the respective IOL Manufac-
turer to get information on optimised IOL constants for an individual
set of lenses used. An alternative source for IOL constants optimised
for optical biometry is the homepage of the "User Group for Laser In-
terference biometry" (ULIB) of the University of Wuerzburg, Germany.
Even tough the constants published there have been optimised for a
different optical biometer than the LS 900
reviewed studies [1, 2, 3] indicate that ULIB published data can be
used to calculate IOL power in connection with the LS 900
To further improve the outcome of the IOL calculation, it is recommen-
ded that every surgeon creates personalised IOL constants based on
pre-operative data generated with the LS 900
refraction analysis at least 3 month post-operative.

.. References

[1] P J Buckhurst, J S Wolffsohn, S Shah, S A Naroo, L N Davies,
E J Berrow, "A new optical low coherence reflectometry device for
ocular biometry in cataract patients", British Journal of Ophthalmo-
logy 2009;93:949-953
[2] M P Holzer, M Mamusa, G U Auffarth, „Accuracy of a new parti-
al coherence interferometry analyser for biometry measurements",
British Journal of Ophthalmology 2009;93: 807-810
[3] K Rohrer, B E Frueh, R Wälti, I A Clemetson, C Tappeiner, D
Goldblum, "Comparison and Evaluation of Ocular Biometry Using a
New Noncontact Optical Low-Coherence Reflectometer", accepted
for publication in Ophthalmology

. IOL constants

It is recommended to use personalised IOL constants to achieve
maximum prediction accuracy of the IOL calculation. Using perso-
nalised IOL constants minimises the effects of individual surgical
techniques, individual measurement- and surgical-equipment, ocu-
lar dimensions and ethnic specialities of a patient population on the
IOL calculation.

.. IOL constants derived using optical measurements

If there are optimised or even personalised IOL constants available
from a different optical biometer than the LS 900
as well with the LS 900 to achieve clinically identical results [1,2,3].
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Optimised constants for optical biometers can also be found on the
web site of the "User Group for Laser Interference Biometry" (ULIB)
of the University of Wuerzburg, Germany.
.. IOL constants derived using immersion ultrasound
measurements
If there are optimised IOL constants available for immersion ultra-
sound, they may be used as a starting point for IOL calculation with
the LS 900 . Still differences in IOL calculation may occur due to dif-
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ferences in the keratometry measurements of the LS 900
keratometer used in combination with the immersion ultrasound. A
comprehensive manual how to convert existing ultrasound biometry
optimised IOL constants to optical biometry optimised IOL constants
can be found on the web site of the "User Group for Laser Inter-
cannot monitor
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are one central element
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, recently published, peer
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.
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and data from a stable
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, they may be used
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and the
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