Lateral shearing interferometry, dynamic wavefront sensing, and high-speed videokeratoscopy for noninvasive assessment of tear film surface characteristics: a comparative study

Dorota H. Szczesna, David Alonso-Caneiro, D. Robert Iskander, Scott A. Read, Michael J. Collins
2010 Journal of Biomedical Optics  
There are several noninvasive techniques for assessing the kinetics of tear film, but no comparative studies have been conducted to evaluate their efficacies. Our aim is to test and compare techniques based on high-speed videokeratoscopy ͑HSV͒, dynamic wavefront sensing ͑DWS͒, and lateral shearing interferometry ͑LSI͒. Algorithms are developed to estimate the tear film build-up time T BLD , and the average tear film surface quality in the stable phase of the interblink interval TFSQ Av .
more » ... al TFSQ Av . Moderate but significant correlations are found between T BLD measured with LSI and DWS based on vertical coma ͑Pearson's r 2 = 0.34, p Ͻ 0.01͒ and higher order rms ͑r 2 = 0.31, p Ͻ 0.01͒, as well as between TFSQ Av measured with LSI and HSV ͑r 2 = 0.35, p Ͻ 0.01͒, and between LSI and DWS based on the rms fit error ͑r 2 = 0.40, p Ͻ 0.01͒. No significant correlation is found between HSV and DWS. All three techniques estimate tear film build-up time to be below 2.5 sec, and they achieve a remarkably close median value of 0.7 sec. HSV appears to be the most precise method for measuring tear film surface quality. LSI appears to be the most sensitive method for analyzing tear film build-up.
doi:10.1117/1.3431103 pmid:20615034 fatcat:7g5i4a5jkvdmfmshbbbw6trcru