الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The technological improvements in optical biometers have made cataract surgery
evolve to the level of refractive surgery. Biometry is one of the key elements for obtaining
satisfactory refractive outcomes after cataract surgery. Visual outcomes after cataract
surgery depend on the minimization of errors associated with the measurement of ocular
parameters.
Modern technology has significantly improved our ability to accurately calculate
ocular biometrical parameters. Today, we are more confident fulfilling the expectations of
the patient. However, it is still very important to pay attention to, accurate biometry, and
accurate IOL power formula selection.
Optical biometry for accurate assessment of the AL is increasingly becoming
popular, as it is rapid, easy to use, and a high-resolution, contact-free method.
The aim of the current work was to compare and assess the predictability of both
devices; IOLmaster 700 and Lenstar LS 900 in myopic patients in the determination of the
adequate power of an intraocular lens undergoing phacoemulsification and IOL
implantation.
In the current study, the measurements were taken with the Lenstar 900 and
IOLmaster 700 on 30 eyes with patients aged 19-84 years (43.3% male and 56.7 %
female) listed for phacoemulsification surgery.
The study was approved by the Ethics Committee of Alexandria University.
All eyes were consecutively examined using the two optical biometers (the Lenstar
LS 900 and the IOLmaster 700) before pupillary dilatation by the same physician. SRK T
formula was used for all eyes for calculation of IOL power. The biometry parameters (AL,
K, and ACD) and attempted IOL power calculations by SRK T formula were compared
using IOLmaster 700 and lenstar 900. All measurements were performed by a single
practitioner for both instruments then compared to each other’s.
All patients were performed phacoemulsification surgery and foldable Akreos IOLs
implantation by the same surgeon. Manifest refraction was done to all eyes 4-6 weeks after
surgery as well as calculating the achieved spherical equivalent. The expected refractive
result was emmetropia or as close to emmetropia.
Error in prediction was calculated in all cases as follows: Predicted postoperative
refraction – actual postoperative refractive error in spherical equivalent. Total
Predictability of IOL master 700 ranged from 0.0 – 1.52 D, with mean absolute error ± SD
being 0.54 ± 0.46 D. Total Predictability of Lenstar 900 ranged from 0.0 – 1.01 D, with
mean absolute error ± SD being 0.40 ± 0.32D. The Mann–Whitney–Wilcoxon U test was
used and it revealed no statistical differences between between both methods (p=0.569).
Sensitivity analysis was done for the 2 devices alone for their mean absolute
prediction error at ± 0.50 D, ± 1.00 D, ± 1.50 D and ± 1.75 D.
Summary
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The IOLmaster 700 carried the sensitivity of prediction at ± 0.50 D, ± 1.00 D, ± 1.50
D and ± 1.75 D as it measured 63.3%, 83.3 %, 96.6 % and 100% respectively.
The Lenstar 900 carried the sensitivity of prediction at ± 0.50 D, ± 1.00 D and ± 1.50
D as it measured 70%, 93.3% and 100% respectively.
The axial length by the IOLmaster 700 ranged from 24.03 mm to 30.72 mm, with
mean value ± SD of 26.19 ± 2.18 mm and that of the Lenstar 900 ranged from 24.01 mm to
30.80 mm, with mean value ± SD of 26.20 ± 2.20 mm.
Regarding the keratometric measurements, the average K by the IOLmaster 700
ranged from 41.20 D to 47.53D, with mean value ± SD of 43.90 ± 1.88 D and that of the
Lenstar 900 was from 41.33 D to 47.44 D, with mean value ± SD of 43.94 ± 1.87 D.
Regarding the ACD by the IOLmaster 700 ranged from 2.71 mm to 4.17 mm, with
mean value ± SD of 3.44 ± 0.36 mm and that of the Lenstar 900 was from 2.73 mm to 4.21
mm, with mean value ± SD of 3.44 ± 0.34 mm.
The IOL power calculation via SRK/T by the IOLmaster 700 ranged from 3.0 D to
21.0 D, with mean value ± SD of 13.03 ± 6.34 D and that of the Lenstar 900 was from 3.0
D to 21.0 D, with mean value ± SD of 13.02 ± 6.45 D.
The predicted refraction by the IOLmaster 700 ranged from -0.47 D to -0.02 D with
mean value ± SD of -0.18 ± 0.10 D and that of the Lenstar 900 ranged from -0.47 D to -
0.02 D with mean value ± SD of -0.20 ± 0.10 D.
The results showed that there were no significant statistical differences between the
measurements of the two devices as regards to AL, average K, ACD and predicted
refraction using the paired t test, Correlation, Intraclass correlation coefficient and Bland-
Altman plot.