Objective measurements of the longitudinal chromatic aberration of the human eye

Charman, W. N.; Jennings, J. A. M.

doi:10.1016/0042-6989(76)90232-7

Cited by 100 publications

(61 citation statements)

References 33 publications

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“…Wavelength differ-ences in reflectivity of different retinal layers do not seem to affect the aberration pattern measured. 16,17 Except for the defocus term, whose difference is consistent with the chromatic difference in focus, [18][19][20] no significant differences are found with use of IR or green light. 16,17 Polarized light also interacts with the ocular optical components and the retina.…”

Section: Introductionmentioning

confidence: 80%

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

et al. 2002

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Ocular aberrations were measured in 71 eyes by using two reflectometric aberrometers, employing laser ray tracing (LRT) (60 eyes) and a Shack-Hartmann wave-front sensor (S-H) (11 eyes). In both techniques a point source is imaged on the retina (through different pupil positions in the LRT or a single position in the S-H). The aberrations are estimated by measuring the deviations of the retinal spot from the reference as the pupil is sampled (in LRT) or the deviations of a wave front as it emerges from the eye by means of a lenslet array (in the S-H). In this paper we studied the effect of different polarization configurations in the aberration measurements, including linearly polarized light and circularly polarized light in the illuminating channel and sampling light in the crossed or parallel orientations. In addition, completely depolarized light in the imaging channel was obtained from retinal lipofuscin autofluorescence. The intensity distribution of the retinal spots as a function of entry (for LRT) or exit pupil (for S-H) depends on the polarization configuration. These intensity patterns show bright corners and a dark area at the pupil center for crossed polarization, an approximately Gaussian distribution for parallel polarization and a homogeneous distribution for the autofluorescence case. However, the measured aberrations are independent of the polarization states. These results indicate that the differences in retardation across the pupil imposed by corneal birefringence do not produce significant phase delays compared with those produced by aberrations, at least within the accuracy of these techniques. In addition, differences in the recorded aerial images due to changes in polarization do not affect the aberration measurements in these reflectometric aberrometers.

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Section: Introductionmentioning

confidence: 80%

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

et al. 2002

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“…Focus was checked on individual cells (especially those with high resolution) by inserting accessory lenses in front of the eye. When coloured gratings were used, a difference in focus of about +0-25 dioptres relative to white might be anticipated due to longitudinal chromatic aberration of the eye (Charman & Jennings, 1976), and we sometimes tested whether additional focus correction improved responses. This was generally not the case.…”

Section: Methodsmentioning

confidence: 99%

Visual resolution of macaque retinal ganglion cells.

Crook

Lange-Malecki

Lee

et al. 1988

The Journal of Physiology

125

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SUMMARY1. The visual resolving ability of different types of macaque retinal ganglion cells was estimated at different retinal eccentricities, by measuring the amplitude of modulated responses to black-white gratings of spatial frequencies near the resolution limit for each cell.2. The resolving ability of tonic, spectrally opponent ganglion cells was usually similar to that of phasic, non-opponent ganglion cells at similar eccentricities, except that at eccentricities greater than 10 deg some tonic ganglion cells with remarkably high resolution (up to ca. 15 cycles/deg) were found. Our cell sample was limited within the central 2 deg of the visual field, however.3. Only a small proportion of phasic ganglion cells showed an increase of mean firing level to gratings near the resolution limit. The maintained firing of tonic ganglion cells was higher than that of phasic ganglion cells.4. With red-black or green-black gratings, the resolution of phasic ganglion cells was unaffected. For red or green on-centre ganglion cells. a marked deterioration of resolving ability occurred when the grating was of a colour to which a cell responded poorly (green-black gratings for red on-centre cells. and red-black gratings for green on-centre cells). A slight improvement in resolving ability occurred when the grating was of an excitatory colour.5. For a sub-sample of cells. we compared resolution limit with centre size as determined from area-threshold curves. For both phasic and tonic ganglion cells, resolution limit (the period length just resolved) was about half the centre diameter, as is the case for cat ganglion cells. This implies that the centre sizes of phasic and tonic monkey ganglion cells are similar at most eccentricities.6. We attempt to relate these results to primate retinal anatomy and visual resolution, determined behaviourally.

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“…large residual responses were observed with borders between 570 and 642 nm lights, but no residual responses were observed with borders between 510 and 440 nm, this latter pair lying close to a tritanopic confusion line. A longitudinal chromatic aberration of 0-3 dioptres would be expected in the former case, and a greater aberration of 0-7 dioptres in the latter (Charman & Jennings, 1976).…”

Section: Ganglion Cell Border Responsesmentioning

confidence: 99%

“…This is consistent with the visual resolution of parafoveal phasic cells (Crook, LangeMalecki, . A chromatic aberration of at least one dioptre would be required to produce an artifact of this magnitude (Gubisch, 1967;Charman & Jennings, 1976).…”

Section: Ganglion Cell Border Responsesmentioning

confidence: 99%

The physiological basis of the minimally distinct border demonstrated in the ganglion cells of the macaque retina.

Kaiser

Lee

Martin

et al. 1990

The Journal of Physiology

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SUMMARY1. The minimally distinct border method involves setting the relative radiances of two adjacent, differently coloured fields until the border between them is minimally distinct. At these radiance settings, the two fields are found to be of equal luminance. The task shares with flicker photometry all the requirements of a photometric method.2. We have recorded responses of macaque ganglion cells to such borders moved back and forth across the receptive field; the size of the luminance step across the border was systematically varied.3. Phasic ganglion cells gave transient responses to such borders, consisting of an increase or decrease in firing rate depending on direction of luminance contrast and cell type (on-or off-centre). Tonic ganglion cells gave sustained responses dependent on chromatic contrast across the border.4. An analysis of phasic cell responses showed a minimum near equal luminance, suggesting their signal could readily support the minimally distinct border task. We could not devise a scheme whereby tonic cells could support the task.5. Spectral sensitivity of phasic cells, determined from their minima, closelv resembled the 10 deg luminous efficiency function, as required of a mechanism underlying the psychophysical performance.6. For phasic cells, the minimum was independent of movement speed, and hence of eye movement velocity under natural viewing conditions. 7. Proportionality, additivity and transitivity are found psychophysically with the minimally distinct border method. All these properties were also exhibited by phasic cell responses.8. Residual responses were present in individual phasic cells to equal-luminance borders, probably due to a non-linearity of M-and L-cone summation. The

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Objective measurements of the longitudinal chromatic aberration of the human eye

Cited by 100 publications

References 33 publications

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

Visual resolution of macaque retinal ganglion cells.

The physiological basis of the minimally distinct border demonstrated in the ganglion cells of the macaque retina.

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