March 2012
Volume 53, Issue 14
Free
ARVO Annual Meeting Abstract  |   March 2012
Data Reduction Strategies for Aberration Measurements in Tohono O’odham Infants and Children
Author Affiliations & Notes
  • Joseph M. Miller
    Ophthalmology and Vision Science,
    Optical Sciences,
    University of Arizona, Tucson, Arizona
  • Jim Schwiegerling
    Optical Sciences,
    University of Arizona, Tucson, Arizona
  • Erin M. Harvey
    Ophthalmology and Vision Science,
    College Public Health,
    University of Arizona, Tucson, Arizona
  • Duane L. Sherrill
    College Public Health,
    University of Arizona, Tucson, Arizona
  • Dawn H. Messer
    Ophthalmology and Vision Science,
    University of Arizona, Tucson, Arizona
  • J D. Twelker
    Ophthalmology and Vision Science,
    College Public Health,
    University of Arizona, Tucson, Arizona
  • Footnotes
    Commercial Relationships  Joseph M. Miller, None; Jim Schwiegerling, None; Erin M. Harvey, None; Duane L. Sherrill, None; Dawn H. Messer, None; J. D. Twelker, None
  • Footnotes
    Support  NEI 13153, RPB
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 3592. doi:
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    • Get Citation

      Joseph M. Miller, Jim Schwiegerling, Erin M. Harvey, Duane L. Sherrill, Dawn H. Messer, J D. Twelker; Data Reduction Strategies for Aberration Measurements in Tohono O’odham Infants and Children. Invest. Ophthalmol. Vis. Sci. 2012;53(14):3592.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract
 
Purpose:
 

To compare strategies for the detection of properly focused and aligned images extracted from Shack-Hartman Aberrometer (PeWE) video segments recorded while infants and children viewed a cartoon at a distance of 50 and 200 cm.

 
Methods:
 

Subjects were Tohono O’odham infants and children participating in a longitudinal study of refractive error who were able to cooperate with hand-held video recording (PeWE aberrometer) while viewing a cartoon displayed at 50 cm and 200 cm. A total of 1351 children (658 girls, 693 boys) were examined, with 2485 examinations. Children ranged in age from 0.48 to 9.92 years (average 4.28 years) at their initial exam. Mean M (spherical equivalent, diopters (D)) of lower order aberrations were determined for images recorded while the child viewed cartoons at 50cm (-2D from infinity) and 200cm (-0.50 D from infinity). Mean Delta M (D), as vergence distance changed from 50cm to 200cm, was determined first without any attempt to exclude poorly focused or aligned images, and again, when four different data reduction filters were applied in an attempt to limit the observations to those obtained while the child was viewing the cartoon, and the image was in focus. Filters included: 1-Max,Min Clip to physiologic M, J0 and J45; 2-Human inspection by a single trained observer; 3-Median filtering, based upon the median value of cylinder, and 4: images were matched for corresponding J0 and J45 keratometry measurements obtained with a hand-held keratometer (IK4). For methods 3 and 4, it was assumed accommodation did not change astigmatism, and that as the child looked away from the center of the cartoon, astigmatism of oblique incidence would change PeWE astigmatism.

 
Results:
 

The human observer was best able to detect images that appeared to be in focus and properly aligned, with a mean delta M most closely approaching the theoretical -1.5D shift in vergence, at the smallest standard deviation. Mean delta M, even with no filtration, was significant (p<0.001) in all cases, largelybecause of the large sample size.

 
Conclusions:
 

Lower order aberration changes were documented with the use of the PeWE in all cases. The human observer provided the most precise method of detecting on-axis, focused images.  

 
Keywords: visual development • astigmatism • clinical research methodology 
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