Purchase this article with an account.
Aixa Alarcon, Famya Baig, Len Zheleznyak, Geunyoung Yoon; Investigating the accommodative response with different sign and magnitudes of spherical aberration.. Invest. Ophthalmol. Vis. Sci. 2014;55(13):5969.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
It has been found that the ocular higher aberrations may have a significant impact on the accommodative response. The goal of this study was to investigate the effects of sign and magnitude of SA on the accommodative response when distance image quality is optimized.
The monocular accommodative response of 4 dilated subjects (phenylephrine 1%) was measured in monochromatic light (550nm) with a 5.8mm artificial pupil. An adaptive optics vision simulator corrected subjects’ native aberrations and induced four values of SA (±0.5 and ±1μm) and defocus to stimulate the near vergence. The visual Strehl ratio was used to determine a shift in the best focus when each SA was induced and AO was then used to optimize visual quality for distance before stimulating accommodation. Subjects fixated on a Maltese cross at 0D for 10 seconds, after which a near stimulus was presented for 10 seconds at either 1.5 or 3D. Each trial was repeated 5 times per condition. Defocus and higher order aberrations were recorded at 7Hz with a custom-built Shack-Hartmann wavefront sensor. The accommodative response was quantified from the recorded wavefront aberrations. The accommodative response was fit to a Boltzmann sigmoidal function to quantify the accommodative lag and latency.
Accommodative lag was lowest with 0μm SA (0.48±0.21D and 0.49±0.52D for 1.5 and 3D stimuli, respectively). NSA provided larger accommodative lag than PSA (p<0.05, Student’s t-test) for 3D of accommodative demand (2.11±0.69D and 1.25±0.81D, respectively). With an accommodative demand of 1.5D, NSA and PSA provided similar accommodative lag (0.97±0.36D and 0.80±0.28D respectively, p=0.11). Differences in lag between PSA and NSA were larger for 0.5 than for 1μm of SA at both target vergences (p<0.001 for all subjects). For 1μm SA, the difference was significant only for 3D target vergence (p<0.05 for all subjects). No significant differences were found on the latency of the accommodation response as a function of the magnitude of the SA.
Negative SA led to a larger accommodative lag than positive SA when distance image quality was optimized. Differences between negative and positive SA were reduced for larger magnitudes of SA and lower accommodative demands.
This PDF is available to Subscribers Only