Abstract

The adaptive optics scanning laser ophthalmoscope has been fitted with three light sources of different wavelengths to allow simultaneous or separate imaging with one, two or three wavelength combinations. The source wavelengths used are 532 nm, 658 nm and 840 nm. Typically the instrument is used in dual-frame mode, performing imaging at 840 nm and precisely coincident retinal stimulation in one of the visible wavelengths. Instrument set-up and single-detector image capture are described. Simultaneous multi-wavelength imaging in the living human retina is demonstrated. The chromatic aberrations of the human eye lead to lateral and axial shifts, as well as magnification differences in the image, from one wavelength to another. Measurement of these chromatic effects is described for instrument characterization purposes.

© 2006 Optical Society of America

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References

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  1. A. Roorda, F. Romero-Borja, W. Donnelly, III, H. Queener, T. Hebert, and M. Campbell, "Adaptive optics scanning laser ophthalmoscopy," Opt. Express 10,405-412 (2002).
    [PubMed]
  2. J. A. Martin. and A. Roorda, "Direct and non-invasive assessment of Parafoveal Capillary Leukocyte Velocity," Ophthalmology 112, 2219-2224 (2005).
    [CrossRef] [PubMed]
  3. S. Poonja, S. Patel, L. Henry, and A. Roorda, "Dynamic visual stimulus presentation in an adaptive optics scanning laser ophthalmoscope," Journal of Refractive Surgery 21,575-580 (2005).
  4. F. Reinholz, R. A. Ashman, and R. H. Eikelboom, "Simultaneous three wavelength imaging with a scanning Laser Ophthalmoscope," Cytometry 37,165-170 (1999).
    [CrossRef] [PubMed]
  5. Y. Zhang, S. Poonja, and A. Roorda, "MEMS-based adaptive optics scanning Laser Ophthalmoscopy," Opt. Lett. 31, 1268-1270 (2006).
    [CrossRef] [PubMed]
  6. D. C. Gray, W. Merigan, J. I. Wolfing, B. P. Gee, J. Porter, A. Dubra, T. H. Twietmeyer, K. Ahamd, R. Tumbar, F. Reinholz, and D. R. Williams, "In vivo fluorescence imaging of primate retinal ganglion cells and retinal pigment epithelial cells," Opt. Express 14, 7144-7158 (2006).
    [CrossRef] [PubMed]
  7. P. A. Howarth, and A. Bradley, "The Longitudinal chromatic aberration of the human eye, and its correction," Vision Res. 26, 361-366 (1986).
    [CrossRef] [PubMed]
  8. L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
    [CrossRef] [PubMed]
  9. P. Simonet, and M. C. W. Campbell, "The optical transverse chromatic aberration on the Fovea of the human eye," Vision Res. 30,187-206 (1990).
    [CrossRef] [PubMed]
  10. C. Wildsoet, D. A. Atchison, and M. J. Collins, "Longitudinal chromatic aberration as a function of refractive error," Clin. Exper. Optom. 76,119-122 (1993).
    [CrossRef]
  11. E. Fernandez, A. Unterhuber, B. Povazay, B. Hermann, P. Artal, and W. Drexler, "Chromatic aberration correction of the human eye for retinal imaging in the near infrared," Opt. Express 14, 6213-6225 (2006).
    [CrossRef] [PubMed]
  12. X. Zhang, L. N. Thibos, and A. Bradley, "Relation between the chromatic difference of refraction and the chromatic difference of magnification for the reduced eye," Optom Vision Sci. 68, 456-458 (1991).
    [CrossRef]
  13. X. Zhang, A. Bradley, and L. N. Thibos, "Experimental determination of the chromatic difference of magnification of the human eye and the location of the anterior nodal point," J. Opt. Soc. Am. A 10, 213-220 (1993).
    [CrossRef] [PubMed]
  14. Safe Use of Lasers, ANSI Z136.1-1993. New York: American National Standards Institute (1993) and ANSI, American National Standard for the Safe Use of Lasers, ANSI Z136.1 (Laser Institute of America, Orlando, FL, 2000).
  15. Y. Zhang and A. Roorda, "Evaluating the lateral resolution of the adaptive optics scanning Laser Ophthalmoscope," J. Biomed. Opt. 11, 014002 (2006).
    [CrossRef] [PubMed]
  16. K. Venkateswaran, F. Romero-Borja, and A. Roorda, "Theoretical modeling and evaluation of the axial resolution of the Adaptive Optics Scanning Laser Ophthalmoscope," J. Biomed. Opt. 9, 132-138 (2004).
    [CrossRef] [PubMed]
  17. S. Marcos, S. A. Burns, E. Moreno-Barriusop, and R. Navarro, "A new approach to the study of ocular chromatic aberrations," Vision Res. 39,4309-4323 (1999).
    [CrossRef]
  18. S. B. Stevenson and A. Roorda, "Correcting for miniature eye movements in high resolution scanning Laser Ophthalmoscopy" in Ophthalmic Technologies XV, F. Manns, P. Soderberg, and A. Ho, eds., Proc. SPIE Vol. 5688A, 145-151 (2005).
    [CrossRef]
  19. C. R. Vogel, D. W. Arathorn, A. Roorda, and A. Parker, "Retinal motion estimation in Adaptive Optics Scanning Laser Ophthalmoscopy," Opt. Express 14,487-497 (2006).
    [CrossRef] [PubMed]
  20. H. Hofer, L. Chen, G. -Y. Yoon, B. Singer, Y. Yamauchi and D. R. Williams, "Improvement in retinal image quality with dynamic correction of the eye's aberrations," Opt. Express 8, 631-643 (2001).
    [CrossRef] [PubMed]
  21. A. Roorda and D. R. Williams, "The arrangement of the three cone classes in the living human eye," Nature 397, 520-522 (1999).
    [CrossRef] [PubMed]
  22. J. I. YellotJr, "Spectral analysis of spatial sampling by photoreceptors: Topological disorder prevents aliasing," Vision Res. 22, 1205-1210 (1982).
    [CrossRef]

2006

2005

J. A. Martin. and A. Roorda, "Direct and non-invasive assessment of Parafoveal Capillary Leukocyte Velocity," Ophthalmology 112, 2219-2224 (2005).
[CrossRef] [PubMed]

S. Poonja, S. Patel, L. Henry, and A. Roorda, "Dynamic visual stimulus presentation in an adaptive optics scanning laser ophthalmoscope," Journal of Refractive Surgery 21,575-580 (2005).

2004

K. Venkateswaran, F. Romero-Borja, and A. Roorda, "Theoretical modeling and evaluation of the axial resolution of the Adaptive Optics Scanning Laser Ophthalmoscope," J. Biomed. Opt. 9, 132-138 (2004).
[CrossRef] [PubMed]

2002

2001

1999

A. Roorda and D. R. Williams, "The arrangement of the three cone classes in the living human eye," Nature 397, 520-522 (1999).
[CrossRef] [PubMed]

S. Marcos, S. A. Burns, E. Moreno-Barriusop, and R. Navarro, "A new approach to the study of ocular chromatic aberrations," Vision Res. 39,4309-4323 (1999).
[CrossRef]

F. Reinholz, R. A. Ashman, and R. H. Eikelboom, "Simultaneous three wavelength imaging with a scanning Laser Ophthalmoscope," Cytometry 37,165-170 (1999).
[CrossRef] [PubMed]

1993

1991

X. Zhang, L. N. Thibos, and A. Bradley, "Relation between the chromatic difference of refraction and the chromatic difference of magnification for the reduced eye," Optom Vision Sci. 68, 456-458 (1991).
[CrossRef]

1990

L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
[CrossRef] [PubMed]

P. Simonet, and M. C. W. Campbell, "The optical transverse chromatic aberration on the Fovea of the human eye," Vision Res. 30,187-206 (1990).
[CrossRef] [PubMed]

1986

P. A. Howarth, and A. Bradley, "The Longitudinal chromatic aberration of the human eye, and its correction," Vision Res. 26, 361-366 (1986).
[CrossRef] [PubMed]

1982

J. I. YellotJr, "Spectral analysis of spatial sampling by photoreceptors: Topological disorder prevents aliasing," Vision Res. 22, 1205-1210 (1982).
[CrossRef]

Ahamd, K.

Arathorn, D. W.

Artal, P.

Ashman, R. A.

F. Reinholz, R. A. Ashman, and R. H. Eikelboom, "Simultaneous three wavelength imaging with a scanning Laser Ophthalmoscope," Cytometry 37,165-170 (1999).
[CrossRef] [PubMed]

Atchison, D. A.

C. Wildsoet, D. A. Atchison, and M. J. Collins, "Longitudinal chromatic aberration as a function of refractive error," Clin. Exper. Optom. 76,119-122 (1993).
[CrossRef]

Bradley, A.

X. Zhang, A. Bradley, and L. N. Thibos, "Experimental determination of the chromatic difference of magnification of the human eye and the location of the anterior nodal point," J. Opt. Soc. Am. A 10, 213-220 (1993).
[CrossRef] [PubMed]

X. Zhang, L. N. Thibos, and A. Bradley, "Relation between the chromatic difference of refraction and the chromatic difference of magnification for the reduced eye," Optom Vision Sci. 68, 456-458 (1991).
[CrossRef]

L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
[CrossRef] [PubMed]

P. A. Howarth, and A. Bradley, "The Longitudinal chromatic aberration of the human eye, and its correction," Vision Res. 26, 361-366 (1986).
[CrossRef] [PubMed]

Burns, S. A.

S. Marcos, S. A. Burns, E. Moreno-Barriusop, and R. Navarro, "A new approach to the study of ocular chromatic aberrations," Vision Res. 39,4309-4323 (1999).
[CrossRef]

Campbell, M.

Campbell, M. C. W.

P. Simonet, and M. C. W. Campbell, "The optical transverse chromatic aberration on the Fovea of the human eye," Vision Res. 30,187-206 (1990).
[CrossRef] [PubMed]

Chen, L.

Collins, M. J.

C. Wildsoet, D. A. Atchison, and M. J. Collins, "Longitudinal chromatic aberration as a function of refractive error," Clin. Exper. Optom. 76,119-122 (1993).
[CrossRef]

Donnelly, W.

Drexler, W.

Dubra, A.

Eikelboom, R. H.

F. Reinholz, R. A. Ashman, and R. H. Eikelboom, "Simultaneous three wavelength imaging with a scanning Laser Ophthalmoscope," Cytometry 37,165-170 (1999).
[CrossRef] [PubMed]

Fernandez, E.

Gee, B. P.

Gray, D. C.

Hebert, T.

Henry, L.

S. Poonja, S. Patel, L. Henry, and A. Roorda, "Dynamic visual stimulus presentation in an adaptive optics scanning laser ophthalmoscope," Journal of Refractive Surgery 21,575-580 (2005).

Hermann, B.

Hofer, H.

Howarth, P. A.

L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
[CrossRef] [PubMed]

P. A. Howarth, and A. Bradley, "The Longitudinal chromatic aberration of the human eye, and its correction," Vision Res. 26, 361-366 (1986).
[CrossRef] [PubMed]

Marcos, S.

S. Marcos, S. A. Burns, E. Moreno-Barriusop, and R. Navarro, "A new approach to the study of ocular chromatic aberrations," Vision Res. 39,4309-4323 (1999).
[CrossRef]

Martin, J. A.

J. A. Martin. and A. Roorda, "Direct and non-invasive assessment of Parafoveal Capillary Leukocyte Velocity," Ophthalmology 112, 2219-2224 (2005).
[CrossRef] [PubMed]

Merigan, W.

Moreno-Barriusop, E.

S. Marcos, S. A. Burns, E. Moreno-Barriusop, and R. Navarro, "A new approach to the study of ocular chromatic aberrations," Vision Res. 39,4309-4323 (1999).
[CrossRef]

Navarro, R.

S. Marcos, S. A. Burns, E. Moreno-Barriusop, and R. Navarro, "A new approach to the study of ocular chromatic aberrations," Vision Res. 39,4309-4323 (1999).
[CrossRef]

Parker, A.

Patel, S.

S. Poonja, S. Patel, L. Henry, and A. Roorda, "Dynamic visual stimulus presentation in an adaptive optics scanning laser ophthalmoscope," Journal of Refractive Surgery 21,575-580 (2005).

Poonja, S.

Y. Zhang, S. Poonja, and A. Roorda, "MEMS-based adaptive optics scanning Laser Ophthalmoscopy," Opt. Lett. 31, 1268-1270 (2006).
[CrossRef] [PubMed]

S. Poonja, S. Patel, L. Henry, and A. Roorda, "Dynamic visual stimulus presentation in an adaptive optics scanning laser ophthalmoscope," Journal of Refractive Surgery 21,575-580 (2005).

Porter, J.

Povazay, B.

Queener, H.

Reinholz, F.

Romero-Borja, F.

K. Venkateswaran, F. Romero-Borja, and A. Roorda, "Theoretical modeling and evaluation of the axial resolution of the Adaptive Optics Scanning Laser Ophthalmoscope," J. Biomed. Opt. 9, 132-138 (2004).
[CrossRef] [PubMed]

A. Roorda, F. Romero-Borja, W. Donnelly, III, H. Queener, T. Hebert, and M. Campbell, "Adaptive optics scanning laser ophthalmoscopy," Opt. Express 10,405-412 (2002).
[PubMed]

Roorda, A.

Y. Zhang, S. Poonja, and A. Roorda, "MEMS-based adaptive optics scanning Laser Ophthalmoscopy," Opt. Lett. 31, 1268-1270 (2006).
[CrossRef] [PubMed]

Y. Zhang and A. Roorda, "Evaluating the lateral resolution of the adaptive optics scanning Laser Ophthalmoscope," J. Biomed. Opt. 11, 014002 (2006).
[CrossRef] [PubMed]

C. R. Vogel, D. W. Arathorn, A. Roorda, and A. Parker, "Retinal motion estimation in Adaptive Optics Scanning Laser Ophthalmoscopy," Opt. Express 14,487-497 (2006).
[CrossRef] [PubMed]

S. Poonja, S. Patel, L. Henry, and A. Roorda, "Dynamic visual stimulus presentation in an adaptive optics scanning laser ophthalmoscope," Journal of Refractive Surgery 21,575-580 (2005).

J. A. Martin. and A. Roorda, "Direct and non-invasive assessment of Parafoveal Capillary Leukocyte Velocity," Ophthalmology 112, 2219-2224 (2005).
[CrossRef] [PubMed]

K. Venkateswaran, F. Romero-Borja, and A. Roorda, "Theoretical modeling and evaluation of the axial resolution of the Adaptive Optics Scanning Laser Ophthalmoscope," J. Biomed. Opt. 9, 132-138 (2004).
[CrossRef] [PubMed]

A. Roorda, F. Romero-Borja, W. Donnelly, III, H. Queener, T. Hebert, and M. Campbell, "Adaptive optics scanning laser ophthalmoscopy," Opt. Express 10,405-412 (2002).
[PubMed]

A. Roorda and D. R. Williams, "The arrangement of the three cone classes in the living human eye," Nature 397, 520-522 (1999).
[CrossRef] [PubMed]

Simonet, P.

P. Simonet, and M. C. W. Campbell, "The optical transverse chromatic aberration on the Fovea of the human eye," Vision Res. 30,187-206 (1990).
[CrossRef] [PubMed]

Singer, B.

Still, D. L.

L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
[CrossRef] [PubMed]

Thibos, L. N.

X. Zhang, A. Bradley, and L. N. Thibos, "Experimental determination of the chromatic difference of magnification of the human eye and the location of the anterior nodal point," J. Opt. Soc. Am. A 10, 213-220 (1993).
[CrossRef] [PubMed]

X. Zhang, L. N. Thibos, and A. Bradley, "Relation between the chromatic difference of refraction and the chromatic difference of magnification for the reduced eye," Optom Vision Sci. 68, 456-458 (1991).
[CrossRef]

L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
[CrossRef] [PubMed]

Tumbar, R.

Twietmeyer, T. H.

Unterhuber, A.

Venkateswaran, K.

K. Venkateswaran, F. Romero-Borja, and A. Roorda, "Theoretical modeling and evaluation of the axial resolution of the Adaptive Optics Scanning Laser Ophthalmoscope," J. Biomed. Opt. 9, 132-138 (2004).
[CrossRef] [PubMed]

Vogel, C. R.

Wildsoet, C.

C. Wildsoet, D. A. Atchison, and M. J. Collins, "Longitudinal chromatic aberration as a function of refractive error," Clin. Exper. Optom. 76,119-122 (1993).
[CrossRef]

Williams, D. R.

Wolfing, J. I.

Yamauchi, Y.

Yellot, J. I.

J. I. YellotJr, "Spectral analysis of spatial sampling by photoreceptors: Topological disorder prevents aliasing," Vision Res. 22, 1205-1210 (1982).
[CrossRef]

Yoon, G. -Y.

Zhang, X.

X. Zhang, A. Bradley, and L. N. Thibos, "Experimental determination of the chromatic difference of magnification of the human eye and the location of the anterior nodal point," J. Opt. Soc. Am. A 10, 213-220 (1993).
[CrossRef] [PubMed]

X. Zhang, L. N. Thibos, and A. Bradley, "Relation between the chromatic difference of refraction and the chromatic difference of magnification for the reduced eye," Optom Vision Sci. 68, 456-458 (1991).
[CrossRef]

L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
[CrossRef] [PubMed]

Zhang, Y.

Y. Zhang, S. Poonja, and A. Roorda, "MEMS-based adaptive optics scanning Laser Ophthalmoscopy," Opt. Lett. 31, 1268-1270 (2006).
[CrossRef] [PubMed]

Y. Zhang and A. Roorda, "Evaluating the lateral resolution of the adaptive optics scanning Laser Ophthalmoscope," J. Biomed. Opt. 11, 014002 (2006).
[CrossRef] [PubMed]

Clin. Exper. Optom.

C. Wildsoet, D. A. Atchison, and M. J. Collins, "Longitudinal chromatic aberration as a function of refractive error," Clin. Exper. Optom. 76,119-122 (1993).
[CrossRef]

Cytometry

F. Reinholz, R. A. Ashman, and R. H. Eikelboom, "Simultaneous three wavelength imaging with a scanning Laser Ophthalmoscope," Cytometry 37,165-170 (1999).
[CrossRef] [PubMed]

J. Biomed. Opt.

Y. Zhang and A. Roorda, "Evaluating the lateral resolution of the adaptive optics scanning Laser Ophthalmoscope," J. Biomed. Opt. 11, 014002 (2006).
[CrossRef] [PubMed]

K. Venkateswaran, F. Romero-Borja, and A. Roorda, "Theoretical modeling and evaluation of the axial resolution of the Adaptive Optics Scanning Laser Ophthalmoscope," J. Biomed. Opt. 9, 132-138 (2004).
[CrossRef] [PubMed]

J. Opt. Soc. Am. A

Journal of Refractive Surgery

S. Poonja, S. Patel, L. Henry, and A. Roorda, "Dynamic visual stimulus presentation in an adaptive optics scanning laser ophthalmoscope," Journal of Refractive Surgery 21,575-580 (2005).

Nature

A. Roorda and D. R. Williams, "The arrangement of the three cone classes in the living human eye," Nature 397, 520-522 (1999).
[CrossRef] [PubMed]

Ophthalmology

J. A. Martin. and A. Roorda, "Direct and non-invasive assessment of Parafoveal Capillary Leukocyte Velocity," Ophthalmology 112, 2219-2224 (2005).
[CrossRef] [PubMed]

Opt. Express

Opt. Lett.

Optom Vision Sci.

X. Zhang, L. N. Thibos, and A. Bradley, "Relation between the chromatic difference of refraction and the chromatic difference of magnification for the reduced eye," Optom Vision Sci. 68, 456-458 (1991).
[CrossRef]

Vision Res.

S. Marcos, S. A. Burns, E. Moreno-Barriusop, and R. Navarro, "A new approach to the study of ocular chromatic aberrations," Vision Res. 39,4309-4323 (1999).
[CrossRef]

P. A. Howarth, and A. Bradley, "The Longitudinal chromatic aberration of the human eye, and its correction," Vision Res. 26, 361-366 (1986).
[CrossRef] [PubMed]

L. N. Thibos, A. Bradley, D. L. Still, X. Zhang, and P. A. Howarth, "Theory and measurement of Ocular Chromatic Aberration," Vision Res. 30,33-49 (1990).
[CrossRef] [PubMed]

P. Simonet, and M. C. W. Campbell, "The optical transverse chromatic aberration on the Fovea of the human eye," Vision Res. 30,187-206 (1990).
[CrossRef] [PubMed]

J. I. YellotJr, "Spectral analysis of spatial sampling by photoreceptors: Topological disorder prevents aliasing," Vision Res. 22, 1205-1210 (1982).
[CrossRef]

Other

S. B. Stevenson and A. Roorda, "Correcting for miniature eye movements in high resolution scanning Laser Ophthalmoscopy" in Ophthalmic Technologies XV, F. Manns, P. Soderberg, and A. Ho, eds., Proc. SPIE Vol. 5688A, 145-151 (2005).
[CrossRef]

Safe Use of Lasers, ANSI Z136.1-1993. New York: American National Standards Institute (1993) and ANSI, American National Standard for the Safe Use of Lasers, ANSI Z136.1 (Laser Institute of America, Orlando, FL, 2000).

Supplementary Material (1)

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Figures (6)

Fig. 1.
Fig. 1.

The multi-wavelength adaptive optics scanning laser ophthalmoscope. Light delivery, wavefront sensing, wavefront compensation, raster scanning, light detection and frame grabbing components are labeled. L# represent lenses while M# represent mirrors. Labels r and p indicate retinal and pupil conjugate points in the optical path. AOM #: acousto-optic modulator, DF#: dichroic filter, EP: entrance pupil, BS: beamsplitter, DM: deformable mirror, HS: horizontal scanner (16 kHz), VS: vertical scanner (30 Hz), LA: lenslet array, CP: confocal pinhole, PMT: photomultiplier tube.

Fig. 2. (a).
Fig. 2. (a).

Dual wavelength (left: red, right: IR) image of the human retina in vivo. This is the raw image captured in real time, where the book-matched (mirror image) pair is seen simultaneously.

Fig. 2. (b).
Fig. 2. (b).

During the image processing stage, the pair is first separated and the right hand image flipped left-right. Each image is then treated to remove distortions caused by the nonuniform scanning velocity as well as eye movements, and often averaged to improve signal to noise. The two wavelength images may then be correlated or compared. The chromatic aberrations of the eye cause the different wavelengths to focus in different retinal planes. The red image (left) is focused in vessels while the IR image (right) is focused in the plane of the cone photoreceptors. 20 raw frames were averaged to produce the images shown here. The stack of processed images is cropped and resized according to the space naturally traced out by the eye movements, resulting in a processed image [Fig. 2(b)] that has a slightly different size and magnification in comparison to the raw image [Fig. 2(a)].

Fig. 3.
Fig. 3.

Live fly-through movie of simultaneous 658 nm (left hand image) and 840 nm (right hand image) in the living human retina. Features such as the cone photoreceptors, blood flow in vessels and the nerve fiber layer are consecutively revealed. Axial chromatic aberrations caused a 0.366 D difference of focusing depth between the 658 nm and 840 nm images in this subject (EAR), and so features that appear first in the left hand image appear several frames later in the right hand image. For ease of display and to reduce file size for this article, movie pixels have been shrunk to half of their original size. [Media 1]

Fig. 4.
Fig. 4.

Measurement of LCA. (a) Coincident peaks of maximum signal magnitude in mean intensity curve and maximum signal at the spatial frequency of the cones in power spectrum, vs diopters of mirror defocus. These curves were computed from a fly-through movie in infrared illumination for subject KFG. (b) Yellot’s ring at best focus on cones (1.75 D), and (c) at a plane far from the photoreceptors (0.25 D) where no ring is present, with annulus marked in red dashed lines.

Fig. 5.
Fig. 5.

Pupil position in millimeters versus TCA in milliradians for one subject (AJR). TCA is shown to vary linearly with pupil position, as predicted [9]. The achromatic axis (i.e. the axis of zero TCA) is indicated by the dashed lines. TCA varies by over 0.5 milliradians, or 100 arc seconds, across the pupil diameter.

Tables (1)

Tables Icon

Table 1. LCA and TCA for three subjects. LCA values compare favorably with those found in references [7, 10, 11] when adjusting for wavelength ranges. Errors quoted on LCA values correspond to the 95 % confidence bounds of the fitted curve. TCA values are sample TCA magnitudes taken at approximately the pupil center, measured as the halfway position between pupil edges as viewed on the wavefront sensor. These values lie within the range of those found in [9] when line of sight is not controlled. Errors quoted are the standard deviations of the peak positions in the correlations between different wavelength image pairs. Inherent errors are present due to fluctuations in electronic signal synchronization that generates the frame, and rounding errors in the image dewarping process.

Metrics