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Optical aberrations Their significance for eye growth regulation?

Optical aberrations Their significance for eye growth regulation?. Chris Wildsoet. Howie Festschrift March 2002. Howie’s Research Exploits. * photorefraction, * exotic animals * Children * Chicks & lenses * aberrations. Howie Always ready for a challenging subject!!.

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Optical aberrations Their significance for eye growth regulation?

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  1. Optical aberrationsTheir significance for eye growth regulation? Chris Wildsoet Howie Festschrift March 2002

  2. Howie’s Research Exploits * photorefraction, * exotic animals * Children * Chicks & lenses * aberrations

  3. Howie Always ready for a challenging subject!!

  4. Howie & some of his reptilean friends

  5. & some of his bird friends

  6. Howie at work

  7. Memories of visits with Howie & Monica Australia - Champagne breakfasts & picnics Boston - the stairs!!

  8. Emmetropization & the role of aberrations

  9. Ocular Aberrations I. Chromatic aberration -A cue to defocus?

  10. Chromatic Aberrration (CA) Chick Studies • Wildsoet, Howland et al • Rohrer & Schaeffel Chick has >3 D CA!

  11. Chromatic aberration not essential to emmetropization? • recovery from form deprivation myopia under yellow light • (Wildsoet, Howland et al, 1993)

  12. Not all wavelengths compatible with emmetropization? • Lens compensation under red light • No compensation under near UV light • (Rohrer & Schaeffel, 1992)

  13. What do accommodation studies tell us about CA as a potential focusing cue?

  14. Accommodation & CA • Fincham • poor accommodation with ML in some subjects • Kroger & Binder • increased accommodation under red light • Kruger lab • accommodation poor when CA cues reversed • over-accommodation with enhanced blue contrast

  15. Accommodation varies with wavelength refractivity? • Increased accommodation under red light (>600 nm) • Cross target at 33 cm • Colored paper response • (Kroger & Binder, 2000)

  16. Eye size varies with wavelength refractivity? • Increased eye growth under red light (623.5 nm) • 623.5 nm • 534.1 nm • 485 nm • (Kroger & Wagner, 1996)

  17. Chromatic aberration as a defocus cueIs there evidence for chromatic tuning? Strong red=overfocused? Strong blue=underfocused?

  18. Blue cones signal hyperopic defocus? • 10 sec recording; 2 D stimulus • Accommodation increases under enhanced blue contrast • 420 nm target, 580 nm background • Normal + no CA • 580 nm background • (Rucker & Kruger, 2001)

  19. A revisit to old data -Emmetropization in chicks shows chromatic tuning! • Eyes become more myopic (grow more?) under blue cf. red light

  20. A revisit to an old paradigmReverse chromatic aberrtation lenses • Question: do reverse CA lenses disrupt emmetropization? (Howland & Wildsoet, on-going)

  21. Ocular Aberrations II. Monochromatic aberration - Cue to defocus or the origin of abnormal eye growth?

  22. Measurement of monochromatic aberration in humans • Howland & Howland aberroscope

  23. Monochromatic aberrations & human myopia • Myopes have lower 4th order aberrations • Some low myopes have highly aberrated eyes • Myopes show more negative SA, especially with accommodation (Collins , Wildsoet & Atchison, 1995)

  24. -6.5 D -0.7 D -11 D RMS=0.63 mm RMS=0.98 mm RMS=0.39 mm Higher order aberrations & human myopia • higher order (3rd+) aberrations increase with myopia • Low myopia: internal & corneal interact to decreasetotal aberrations • High myopia: internal & corneal add up to increase total aberrations • (Marcos et al. 2001)

  25. 2.5 2 1.5 FWHM (min arc) 1 0.5 0 Hyperopes Emmetropes Myopes Refractive Error Type Myopic growth induces aberrations - Hints from chicks • Angular double-pass image width varies slightly with refractive error (Coletta et al, 2000)

  26. SA as a cue to defocus?SA introduces asymmetries in defocused retinal image • -1/8D • MTF with normal SA 0D +1/8D • (Campbell, 2000)

  27. Two other sides of Howie • Hi from Caroline!

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