Purchase this article with an account.
R. Michael, M. Mikielewicz, K. Kotliar, R. I. Barraquer; The Usability of the New Waveform Parameters From the Ocular Response Analyzer in the Characterization of Keratoconus. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4984.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To test the usability of 39 new waveform parameters from ORA to distinguish between normal and keratoconus (KC) eyes, to determine the severity of keratoconus and to evaluate changes after treatment with crosslinking and intrastromal ring segment implantation.
Forty waveform parameters were derived from ORA's aplanation signal curve. Data of 119 subjects were included in the study. We examined the power of discrimination between control subjects (n=48) and KC patients (stages I & II, n=54) using ROC curves. Subsequently the correlation between KC stages and the waveform parameters was tested. Finally, the changes at 4 months after the treatment with crosslinking (n=22) and intrastromal rings (n=39) were evaluated.
The ROC curves of 11 parameters showed excellent results, 22 moderate and 6 parameters proved to give poor results. Although 15 of the parameters demonstrated statistically significant results (p<0.05) the correlations between KC stages and parameters were only moderate (r<0.5). After crosslinking one parameter and after intrastromal ring implantation two parameters showed significant difference between pre and postoperative values (p<0.05).
Most of the new waveform parameters demonstrated good ability to discriminate between keratoconus and normal eyes. The ability to detect the severity of keratoconus was moderate. The changes in the parameter values after treatment were smaller than expected.
This PDF is available to Subscribers Only