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Single IOL surface measurements with UV‐Shack‐Hartmann‐Sensors
Author(s) -
KANNENGIESSER M,
GILLNER M,
LANGENBUCHER A,
JANUNTS E
Publication year - 2012
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2012.s133.x
Subject(s) - repeatability , reproducibility , optics , standard deviation , range (aeronautics) , materials science , sample (material) , residual , curved mirror , computer science , mathematics , physics , statistics , algorithm , composite material , thermodynamics
Purpose Measuring single IOL surface topographies remains a difficult task due to reflexes from the second surface. Currently no commercially system is available for this task. The purpose of this study is to discuss the feasibility of a new and customized UV‐SHS (Shack‐Hartmann‐Sensor) method in the field of measuring individual IOL surfaces. Methods The WaveMaster system (Trioptics, Wedel) represents the SHS technique. It is customized to work in the UV range of light spectrum and eliminates the possibility of back surface reflections. Repeatability and reproducibility measurements are performed before measuring spherical and freeform IOLs of different radii of curvature (ROC) between 6 mm and 20 mm. For validation of the measurement system 2 criteria are applied: The correct measurement of a sample’s ROC and the RMS of the residual (the topography after subtracting the best‐fitted‐sphere). Results The repeatability and reproducibility measurements provide acceptable figures; a measurement of a sample’s ROC takes about 5 seconds and delivers accurate results. The maximum deviation from the theoretical design ROC is about 100 µm while many results show a deviation of some µm. The results for spherical IOLs prove that the device can be applied over the whole range of ROCs. The residuals show an RMS deviation of some µm for spherical surfaces and correspondingly higher values for freeform surfaces. Conclusion The UV‐WaveMaster system is an appropriate device for measuring individual IOL surfaces for a wide range of ROCs making it applicable for quality control for freeform IOL surfaces. The acquisition of the sample’s topography and ROC with its residual is fast and. Future application of the device will show its advantages and limitations in detail.