May 2004
Volume 45, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2004
HARTMANN–SHACK MEASUREMENTS OF IMAGE QUALITY IN THE RAT EYE
Author Affiliations & Notes
  • M.C. W. Campbell
    Department of Physics and School of Optometry,
    University of Waterloo, Waterloo, ON, Canada
  • M.L. Kisilak
    School of Optometry,
    University of Waterloo, Waterloo, ON, Canada
  • N.J. Gibson
    Department of Psychology,
    University of Waterloo, Waterloo, ON, Canada
  • L. Huang
    School of Optometry,
    University of Waterloo, Waterloo, ON, Canada
  • E.L. Irving
    School of Optometry,
    University of Waterloo, Waterloo, ON, Canada
  • Footnotes
    Commercial Relationships  M.C.W. Campbell, None; M.L. Kisilak, None; N.J. Gibson, None; L. Huang, None; E.L. Irving, None.
  • Footnotes
    Support  NSERC, CRC, CFI, PRO, PREA
Investigative Ophthalmology & Visual Science May 2004, Vol.45, 1079. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      M.C. W. Campbell, M.L. Kisilak, N.J. Gibson, L. Huang, E.L. Irving; HARTMANN–SHACK MEASUREMENTS OF IMAGE QUALITY IN THE RAT EYE . Invest. Ophthalmol. Vis. Sci. 2004;45(13):1079.

      Download citation file:


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

      ×
  • Supplements
Abstract

Abstract: : Purpose: The fundus in the small rat eye can be imaged with potentially better resolution than in larger eyes, making it an important animal model. However, fundus image quality will depend on the optical quality of the eye. The source of degradation in the optical point spread function is controversial. Here we objectively assess the optical quality using a Hartmann–Shack device. Methods: The wavefront aberrations of eight eyes of four awake female breeding rats (Long Evans) aged 140 days and raised on a 12 hour light: dark cycle were measured. Measurements were made in 633nm light through plus lenses used to correct the refractive errors estimated from retinoscopy. These were later corrected for lens magnification. Measurements were taken along the optical axis and pupils ranged from 1.6 mm to 3.2 mm. Results: Eyes of all rats measured were highly hyperopic in both retinoscopic and Hartmann–Shack data. The Zernike defocus calculated from the Hartmann–Shack patterns was up to 16D hyperopic. This was 5D more hyperopic than retinoscopy. There was little astigmatism present and no evidence of accommodation. Higher order root mean square wavefront aberrations were larger than in human eyes with corresponding pupil sizes. RMS aberrations increased with increasing pupil size. Hartmann–Shack images had circular gaps, which varied in size and location in the pupil with time. These appear to be due to tear film irregularities, which are different from those in human eyes. Shadows of whiskers sometimes occluded part of the Hartmann–Shack patterns. As well as the effect of classical Zernike aberrations, overall image quality will be adversely affected by poor optical quality of the tear film and diffraction due to the whiskers. Conclusions: Hartmann–Shack measurements can be performed on awake rats. The more hyperopic refraction in the Hartmann–Shack measurements could arise from a combination of chromatic aberration, a difference in the source of the reflection in the two methods and the paraxial nature of the Zernike defocus term. Image quality will be degraded by diffraction and classical monochromatic and chromatic aberrations. Moreover, tear film optical quality will potentially degrade the overall image quality.

Keywords: optical properties • imaging/image analysis: non–clinical • hyperopia 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×