Purchase this article with an account.
K.E. Parker, M.P. Weikert, J.D. Marsack, D.D. Koch, R.A. Applegate; Stability Of Wavefront Error After Blink In LASIK Patients . Invest. Ophthalmol. Vis. Sci. 2006;47(13):54.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
On the assumption that a change in high frequency aberrations immediately after a blink reflect a change in the optical quality of the tears, the purpose is to determine the optical stability of the Zernike 9th radial order RMS wavefront error over 25 seconds before and after wavefront guided LASIK.
Seven of 8 subjects have been recruited from the University of Houston, College of Optometry and have undergone LASIK. All subjects were in good ocular and systemic health. To date pre–op, one month and 6 month post–op data have been analyzed on three subjects. Two of the subjects were male (BH, NL) and one female (WL), ages 24, 30 and 26, respectively. Average refractive error in M, J0, J45 format was: –4.08±1.56 D, 0.23±0.20 D, –0.06±0.12 D. Five repeated wavefront measurements through the Zernike 10th radial order over a 6mm pupil were obtained on the right eye every second up to 25 seconds after blink (total of 125 measurements) using the Complete Ophthalmic Analysis System (COAS) Model G200. Measurements were recorded at the same time of day preoperatively and postoperatively at one month and six months. The 5 measurements of 9th order RMS error obtained at each second were averaged and plotted as a function of time. To begin to examine the optical properties of the eye immediately after a blink, 9th order RMS error was regressed against time to provide slope and intercept values.
Refractive surgery caused patient dependent changes in 9th order RMS wavefront error. For BH the rate of change over 25 seconds was statistically the same (.0013 µm/sec) for pre– and post–surgery at one month and 6 months. 9th order aberrations increased by a factor of 1.7 at one month and 3.8 at 6 months. For NL rate of change was increased at one month from 0 to .0004 µm/second and returned to pre–op values at 6 months. The intercept increased by a factor of 1.6 at one month and returned to pre–op values at 6 months. For WL pre–op 9th order aberrations decreased slightly with time (slope –.00005 µm/second) and increased to .0002 µm/second at 1 month and to .0003 µm/second at 6 months. The intercept increased by a factor of 2.7 at one month and 1.9 at 6 months.
Monitoring high frequency wavefront aberrations as a function of time immediately after a blink documents change in optical quality following LASIK. The rate of change and magnitude of ninth order RMS aberration post–surgery is patient specific. Including all terms in a particular radial order may dilute sensitivity to changing optical properties and using a single high frequency term may prove to be more sensitive.
This PDF is available to Subscribers Only