ฉันรัก
Differences in the measurements and their clinical relevance:
LENSTAR LS 900 vs. IOL Master
Summary:
Are the measurements obtained from a LENSTAR LS 900 comparable to the ones from an IOL Master
and are differences clinically relevant? This is one of the most frequently asked questions by users.
After the introduction of LENSTAR, there have been several studies conducted around the world with
exactly this scope. The results of the studies can be summarised as follows: All measurements showed
very good correlation between LENSTAR and IOL Master. Although there were some statistical
relevant differences between ocular biometry measurements, they were not clinically significant (1, 3, 5, 6)
.
Material and Methods:
All studies have been published in peer-reviewed journals. The participants gave informed consent and
the protocols have been reviewed by an IRB at the respective clinical sites.
Results:
Study
Meas.
Buckhurst 1)
UK
Holzer 2)
Germany
Cruysberg 3)
Netherlands
Rohrer 4)
Switzerland
Rabsilber 5)
Germany
Hoffer 6)
USA
n = 112
IOLM SW V5.x
n = 100
IOLM SW V5.x
n = 38
IOLM SW V3.02
n = 80
IOLM SW V3.01
n = 100
IOLM SW V5.x
n = 100
IOLM SW V5.2
Mean ∆ Mean ∆ Mean ∆ Mean ∆ Mean ∆ Mean ∆
Axiallength 23.25mm *0.01mm 23.58mm 0.01mm 23.92mm *0.03mm 24.1mm 0.00mm 23.55mm 0.00mm 23.71mm *0.03mm
K flat 42.78D -0.04D 42.41D -0.04D 7.80mm *0.01mm 7.74mm 0.01mm 7.77mm 0.01mm
+
43.58D *-0.11D
K steep 43.88D -0.05D 43.33D -0.04D 7.65mm *0.01mm 7.53mm 0.01mm 7.61mm *0.02mm - -
ACD 3.19mm *0.1mm 3.64mm 0.16mm 3.66mm *0.05mm 3.19mm 0.02mm 3.09mm *0.05mm 3.11mm *0.13mm
n = number of patients
Mean = Mean of the LENSTAR measurements
∆ = LENSTAR measurement – IOL Master Measurement
+Only the average K has been assessed in this study.
*Statistically significant difference
Discussion:
Axial length and K-readings did show very good correlation in all studies reported. The ACD
measurement also showed good correlation, however LENSTAR provided slightly deeper ACD
measurements than IOL Master. This finding is in agreement with a study by Meinhardt7) comparing
the IOL Master to the AC-Master. The difference in technology used might account for this. LENSTAR
uses laser interferometry to assess all axial dimensions of the eye, including the ACD; IOL Master uses
a lateral slit illumination and video image analysis to measure ACD.
Take home message:
LENSTAR provides precise measurements, comparable to IOL Master. Furthermore LENSTAR
measures lens thickness, corneal thickness and pupil diameter of the patient, parameters facilitating
the use of latest 4th generation IOL formulae, such as Holladay II or the Olsen formula, in a single
measurement procedure.