Abstract
Purpose: :
A high resolution (HR) aberrometer has been combined with a full gradient corneal topographer (FGCT) to provide spatially registered and temporally proximate wavefront (WF) and corneal topography data. We investigate 1) the precision and accuracy of this instrument for WF measurements and 2) assess the utility of combined HR WF and FGCT data for screening and diagnostic purposes.
Methods: :
Multiple HR WF and FGCT measurements were conducted on each of 34 patients whose clinically assessed manifest refraction sphere (MRS) was in the range +3 to -13 diopters. Multiple measurements were also taken with an industry standard aberrometer of lower spatial resolution. The correlations of these data for each patient were assessed by fitting the measured refraction to both the manifest refraction and the low resolution (LR) WF data. In addition, the HR WF data were analyzed for high spatial frequency content and compared to the spatially registered FGCT raw data.
Results: :
The HR WF data was found to be highly correlated to both the MRS and the LR WF data; the linear fits yielded correlation coefficients R2=0.967 and R2=0.996, respectively. In addition, it was observed that the high spatial frequency content of the HR WF data correlated spatially with FGCT images indicative of tear film break up but not in cases where cataracts were suspected.
Conclusions: :
The HR aberrometer shows excellent correlation to the existing industry standard LR instrument and to MRS. In addition, the high spatial frequency content in the HR WF was often well spatially correlated to tear film breakup which is clearly observable in the FGCT raw image. The HR WF data are also found to be potentially useful in the observation of cataracts.
Keywords: aberrations • cornea: tears/tear film/dry eye • refraction