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Ocular Response Analyzer waveforms analysis in normal and post‐laser in situ keratomileusis eyes
Author(s) -
FRANCO S,
FONSECA V,
LIRA M
Publication year - 2009
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.1755-3768.2009.322.x
Subject(s) - lasik , keratomileusis , ophthalmology , medicine , applanation tonometry , intraocular pressure , optometry , cornea , blood pressure , arterial stiffness
Purpose Many clinicians have noticed that the morphological signal produced by Ocular Response Analyzer (ORA) (Reichert) is a unique “signature” for the eye being measured and suggested that probably there is other valuable information contained in these signals. This study explores the possibility of using information contained in these waveforms comparing them between normal and post‐LASIK eyes. Methods Corneal biomechanical properties of 40 normal eyes and 20 post‐LASIK eyes were obtained with ORA. Corneal thickness was measured with the SP‐100 Handy pachymeter (Tomey). Data aquired by ORA was exported to an Excel worksheet to obtained parameters such as areas of both the applanation and pressure signal curve, area of the “in” and “out” applanation curves, maximum applanation peaks, maximum of the pressure signal. Results There were significant differences between normal eyes and those submitted to LASIK for almost the studied parameters. Normal eyes show a bigger applanation curve area(p<0.001); the first peak maximum as well as its area are higher than for post‐LASIK corneas (p<0.001). For the second peak there are no statistically significant differences between normal and post‐LASIK eyes. Areas of both applanation peaks shows no significant differences for the post‐LASIK eyes (p=0.794) contrary to that observed in normal eyes. Post‐LASIK eyes show a lower maximum for the pressure signal curve and a smaller area for the second half of the pressure curve than for the normal eyes. Conclusion The results obtained indicate that there is more information in ORA measurements than have been used. Some of the corneal biomechanical properties studied, as weel as waveforms, have not the same behavior in normal and in post‐LASIK eyes.