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Design and validation of a scanning Shack Hartmann aberrometer for measurements of the eye over a wide field of view.

Wei X, Thibos L - Opt Express (2010)

Bottom Line: The prototype SSHA successfully measured the off-axis wavefront aberrations over +/- 15 degree visual field within 7 seconds.In two validation experiments with a wide angle model eye, it measured change in defocus aberration accurately (<0.02microm, 4mm pupil) and precisely (<0.03microm, 4mm pupil).A preliminary experiment with a human subject suggests its feasibility in clinical applications.

View Article: PubMed Central - PubMed

Affiliation: School of Optometry, Indiana University, Bloomington, Indiana 47405, USA. weix@indiana.edu

ABSTRACT
Peripheral vision and off-axis aberrations not only play an important role in daily visual tasks but may also influence eye growth and refractive development. Thus it is important to measure off-axis wavefront aberrations of human eyes objectively. To achieve efficient measurement, we incorporated a double-pass scanning system with a Shack Hartmann wavefront sensor (SHWS) to develop a scanning Shack Hartmann aberrometer (SSHA). The prototype SSHA successfully measured the off-axis wavefront aberrations over +/- 15 degree visual field within 7 seconds. In two validation experiments with a wide angle model eye, it measured change in defocus aberration accurately (<0.02microm, 4mm pupil) and precisely (<0.03microm, 4mm pupil). A preliminary experiment with a human subject suggests its feasibility in clinical applications.

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Related in: MedlinePlus

The mean wavefront maps of the five SSHA measurements of a human subject (OS) over +/− 15 degree 2-dimensional visual field (5mm on-axis EP). The missing wavefront maps indicate the failure of SSHA measurements along the corresponding LoS due to strong backward reflection form the system and cornea. The number above the mean wavefront maps represents RMSDev across the five measurements.
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g005: The mean wavefront maps of the five SSHA measurements of a human subject (OS) over +/− 15 degree 2-dimensional visual field (5mm on-axis EP). The missing wavefront maps indicate the failure of SSHA measurements along the corresponding LoS due to strong backward reflection form the system and cornea. The number above the mean wavefront maps represents RMSDev across the five measurements.

Mentions: For each scan, it took less than 8 seconds to measure the eye’s wavefront aberrations along 37 LoS over the central 30° visual field. Due to the strong backward reflection from the system and cornea, the SSHA failed to measure the wavefront aberrations along the LoS along the horizontal visual field. The mean wavefront maps of the five measurements are shown over the actual elliptical entrance pupils (5mm major diameter) in Fig. 5Fig. 5


Design and validation of a scanning Shack Hartmann aberrometer for measurements of the eye over a wide field of view.

Wei X, Thibos L - Opt Express (2010)

The mean wavefront maps of the five SSHA measurements of a human subject (OS) over +/− 15 degree 2-dimensional visual field (5mm on-axis EP). The missing wavefront maps indicate the failure of SSHA measurements along the corresponding LoS due to strong backward reflection form the system and cornea. The number above the mean wavefront maps represents RMSDev across the five measurements.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369549&req=5

g005: The mean wavefront maps of the five SSHA measurements of a human subject (OS) over +/− 15 degree 2-dimensional visual field (5mm on-axis EP). The missing wavefront maps indicate the failure of SSHA measurements along the corresponding LoS due to strong backward reflection form the system and cornea. The number above the mean wavefront maps represents RMSDev across the five measurements.
Mentions: For each scan, it took less than 8 seconds to measure the eye’s wavefront aberrations along 37 LoS over the central 30° visual field. Due to the strong backward reflection from the system and cornea, the SSHA failed to measure the wavefront aberrations along the LoS along the horizontal visual field. The mean wavefront maps of the five measurements are shown over the actual elliptical entrance pupils (5mm major diameter) in Fig. 5Fig. 5

Bottom Line: The prototype SSHA successfully measured the off-axis wavefront aberrations over +/- 15 degree visual field within 7 seconds.In two validation experiments with a wide angle model eye, it measured change in defocus aberration accurately (<0.02microm, 4mm pupil) and precisely (<0.03microm, 4mm pupil).A preliminary experiment with a human subject suggests its feasibility in clinical applications.

View Article: PubMed Central - PubMed

Affiliation: School of Optometry, Indiana University, Bloomington, Indiana 47405, USA. weix@indiana.edu

ABSTRACT
Peripheral vision and off-axis aberrations not only play an important role in daily visual tasks but may also influence eye growth and refractive development. Thus it is important to measure off-axis wavefront aberrations of human eyes objectively. To achieve efficient measurement, we incorporated a double-pass scanning system with a Shack Hartmann wavefront sensor (SHWS) to develop a scanning Shack Hartmann aberrometer (SSHA). The prototype SSHA successfully measured the off-axis wavefront aberrations over +/- 15 degree visual field within 7 seconds. In two validation experiments with a wide angle model eye, it measured change in defocus aberration accurately (<0.02microm, 4mm pupil) and precisely (<0.03microm, 4mm pupil). A preliminary experiment with a human subject suggests its feasibility in clinical applications.

Show MeSH
Related in: MedlinePlus