Purchase this article with an account.
M. Kobayashi, Y. Hirohara, T. Fujikado, T. Mihashi; Variation of Wavefront Aberrations and Luminance Contrast Threshold for 60-Second Non-Blinking Duration Investigated by Using a Binocular Open-View Wavefront Sensor. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1560.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate if the luminance contrast sensitivity varies as the wavefront aberrations vary.
It was reported that wavefront aberrations changed during 60-second non-blinking period (Mihashi, JJO, 2006) and visual acuity also changed during non-blinking period (Ishida, AJO, 2005). We recently developed a binocular open-view Shack-Hartmann wavefront sensor (BOSHWS) (Kobayashi, Applied Optics, 2008) and the device is optimized to investigate binocular vision both objectively and subjectively. As an objective measurement, 24-hz wavefront sensing was performed on both eyes using infrared light (840 nm). As a subjective measurement, psychophysical measurement of luminance contrast sensitivity was performed using a staircase method. A luminance defined Gabor pattern with 6 or 12 cpd was presented for 0.5 seconds just after subject's response. The subject was continuously observing the stimulus thorough a dichroic mirror of the BOSHWS and was responding if he/she detected the stimulus or not while the eyes were measured by the wavefront sensors for 60 seconds. We measured three subjects under two conditions; one was naturally blinking condition and the other was no-blinking condition. Fro non-blinking condition, we measured two subject under topical anesthesia. We calculated a modulation transfer function (MTF) from the measured wavefront aberration and compared MTF with the contrast sensitivity we obtained in the subjective measurement.
Under the natural condition, MTFs for all eyes did not show any systematic time change. Under non-blinking condition, MTF of the left eye of YH decreased from 0.2 to 0.04 during the 60-s measurement. MTFs of the other eyes in this study did not show any systematic changes. In the psychophysical measurements, the subjects responded every second or a bit less frequently. Luminance contrast threshold of subject YH varied from 0.01 to 0.03 under the natural condition while it increased from 0.01 to 0.17 under the non-blinking condition. Luminance contrast threshold of the other subjects did not vary in a systematic manner during the measurement under both conditions.
We find the decrease of the MTF and the increase of the contrast threshold for one out of three subjects. For the two subjects, their wavefront aberrations and their contrast thresholds did not vary, perhaps because we controlled the air conditioning of the experiment space very carefully to preserve the tear film condition.
This PDF is available to Subscribers Only