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H. Jungnickel, H. Babovsky, A. Kiessling, M. Gebhardt, H.-J. Grein, R. Kowarschik; Visual Performance in Real Time Correction of Higher Order Aberrations With Adaptive Optics. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1576.
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© ARVO (1962-2015); The Authors (2016-present)
To test a new adaptive optics setup for correcting higher order aberrations (HOA). This system minimizes the wavefront error. The subjects can evaluate changes in visual performance in real time.
For the measurements a laboratory setup containing a deformable mirror (MIRAO 52-d, Imagine Eyes) and a Shack-Hartmann wavefront sensor (HASO 32, Imagine Eyes) was developed as a closed loop system. The optotypes were presented on a standard 17" TFT display that was inserted into the optical pathway. In this study 16 subjects (23 to 60 years old) without eye diseases were involved. To determine the classical spectacle correction, a subjective refraction was carried out. Wavefront errors of both eyes were measured with the laboratory setup and with a WASCA Analyzer (Carl Zeiss Meditec). The classical spectacle correction and the correction of lower and higher order aberrations were generated with the adaptive optics system. Visual acuity and contrast sensitivity were determined by the Freiburg Visual Acuity & Contrast Test. Furthermore the subjects directly compared the subjective effects of both corrections by observing pictures displayed on the monitor. All trials took place with natural pupil sizes without application of cycloplegic agents.
Zernike coefficients determined with the laboratory setup showed a good agreement with the WASCA Analyzer data. The closed loop system reduced the higher order RMS values from 0.199 µm to 0.072 µm in the median (calculated for a 4.75 mm pupil). Visual acuities obtained with higher order correction were not significantly different to the classical spectacle correction (median of change +0.004 logMAR, p = 0.787). However with regard to the contrast sensitivity improvements of 0.072 logCS (median, p = 0.007) with the full correction were determined. The subjective rating of visual performance by watching color pictures showed an improvement in 59% of the presentations and an equal rating in 11%. In about 30% of the presentations classical correction was preferred.
The laboratory setup provides accurate values of the wavefront errors. Over all HOA corrections seem to induce improvements primarily in contrast sensitivity and less in visual acuity. Subjective rating of visual performance does not correlate with objective measurement in any case.
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