Comparison of Biometric Measurements Obtained Using 2 Noncontact Optical Biometers
Narrative Responses:
Purpose
Evaluation of the measurement accuracy using a new optical biometer AL-Scan (Nidek) and comparison according to the IOL Master V.5.4 (Carl Zeiss Meditec) device.
Methods
In a prospective clinical study biometric measurements along with intra-ocular lens power calculation using the AL-Scan device were performed. 25 eyes of 13 patients were included in the study. Measurements were repeated using the IOL Master V.5.4 device. Results were elaborated using Pearson's correlation (R) for Axial length (AL), mean keratometry (Km), Anterior Chamber Distance (ACD) and IOL calculation (118, SRKT formula).
Results
Mean values and ranges of axial length results were as follows: 24.15 +/- 1.66mm [21.41-26.98] for IOL Master, and 24.18 +/- 1,64mm [21.42-26.96] for AL-Scan. Mean values of keratometry were 44.22 +/- 1.77D [41.51-47.58] for IOL Master and 44.17 +/- 1,79D [41.51-47.40] for AL-Scan (2.4mm diameter). Mean values and ranges of ACD results were as follows: 3.50 +/- 0,57mm [2.24-4.42] for IOL-Matser and 3.53 +/- 0,56mm [2.48-4.39] for AL-Scan. R calculation between results of IOL Master and AL-Scan were respectively: 0,996 for mean AL; 0,996+/-0,003 for mean km; and 0,999 for IOL calculation (SRK T, A const 118).
Conclusion
The AL-Scan device enables to perform accurate and repetitive biometric measurements and intra-ocular lens (IOL) power calculations. IOL calculation results obtained using the AL-Scan device are comparable to those achieved using the IOL Master V.5.4 device.