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Ocular higher-order aberrations and visual performance



Since adaptive optics was first used to correct the monochromatic aberrations of the eye over a decade ago there has been considerable interest in correcting the ocular aberrations beyond defocus and astigmatism. In order to understand the prospective benefits of correcting these higher-order aberrations it is important to study their effect on visual performance. From a clinical perspective it is important to know how different types of aberration can affect visual performance so that wavefront measurements can be better understood. Visual performance is determined by a combination of optical and neural factors. It is important to consider how degradations in the optical quality of the eye can impact the neural processes involved in visual tasks such as object recognition. \ud In this thesis we present a study of the effects of three types of aberration, defocus, coma and secondary astigmatism, on letter recognition and reading performance. In the course of this work we also characterise the repeatability of the Zywave aberrometer, which we used to measure our subjects' ocular wavefronts. We use stimuli that have these aberrations applied in their rendering to examine the differences between these aberrations and how they differ with respect to the visual task. We find that secondary astigmatism causes the largest impairment to both letter recognition and reading performance, followed by defocus. Coma causes comparatively smaller degradations to performance but its effect is different depending on the visual task. We can predict the reduction in performance based on a simple cross-correlation model of letter confusability. The relationship between these predictions and the experimental results are the same for all three aberrations, in the case of single letter recognition. In reading however, the relationship is different for coma. We suggest that coma causes lateral masking effects and may additionally disrupt the planning of eye movements. Coma slows reading, but does not specifically impair word identification whereas defocus and secondary astigmatism do. We attribute disruptions in word identification to the dramatic effects defocus and secondary astigmatism have on the form of a letter

Topics: Ocular aberrations, eye movements, spatial vision, adaptive optics
Year: 2011
OAI identifier:
Provided by: Durham e-Theses

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  1. (1948). A mathematical theory of communication. doi
  2. (1999). A new approach to the study of ocular chromatic aberrations. doi
  3. (2006). A new calibration set of phase plates for ocular aberrometers.
  4. (2004). A population study on changes in wave aberrations with accommodation. doi
  5. (1997). Aberrations and retinal image quality of the normal human eye. doi
  6. (1995). Accommodation to monochromatic and white-light targets. doi
  7. (2008). Accommodation-related changes in monochromatic aberrations of the human eye as a function of age.
  8. (2001). Ad vitellionem paralipomena, quibus astronomiae pars optica traditur
  9. (2001). Age-related changes in monochromatic wave aberrations in the human eye.
  10. (2010). An adaptive algorithm for saccade, andReferences 175 glissade detection in eyetracking data. doi
  11. (2009). An evaluation of the bausch and lomb zywave aberrometer. doi
  12. (1981). An interactive activation model of context eects in letter perception: Part 1. an account of basic doi
  13. (1964). Application of fourier analysis to the modulation response of the eye.
  14. (1968). Application of fourier analysis to the visibility of gratings.
  15. (2002). Are All Aberrations Equal? doi
  16. (2002). Are optical aberrations during accommodation a signi problem for refractive surgery?
  17. (1976). Assymmetry of the perceptual span in reading. doi
  18. (1980). Asymmetry of the eective visual in reading. doi
  19. (1977). Attention and performance vi. doi
  20. (2003). Bene of higher closed-loop bandwidths in ocular adaptive optics. doi
  21. (2009). Binocular adaptive optics simulator. doi
  22. (2006). Binocular coordination of eye movements during reading. doi
  23. (2009). Blur limits for defocus, astigmatism and trefoil. doi
  24. (2002). Calculated impact of higherorder monochromatic aberrations on retinal image quality in a population of human eyes. doi
  25. (1974). Calculation of axial polychromatic optical transfer function. doi
  26. (2008). Calculation of retinal image quality for polychromatic light. doi
  27. (2004). Case-sensitive letter and bigram frequency counts from large-scale english corpora. doi
  28. (1928). Certain topics in telegraph transmission theory. doi
  29. (2002). Changes of ocular aberration with accommodation. doi
  30. (1993). Chromatic aberration and ocular focus: Fincham revisited. doi
  31. (2001). Closed-loop adaptive optics in the human eye. doi
  32. (1999). Comparison of corneal wavefront aberrations after photorefractive keratectomy and laser in situ keratomileusis. doi
  33. (2005). Comparison of higher-order wavefront aberrations with 3 aberrometers. doi
  34. (2001). Compensation of corneal aberrations by the internal optics in the human eye. doi
  35. (2006). Contrast sensitivity function and ocular higher-order aberrations in normal human eyes. doi
  36. (2002). Contribution of the cornea and internal surfaces to the change in ocular aberrations with age. doi
  37. (2005). Corneal wavefront aberration measurements to detect keratoconus patients. doi
  38. (2003). Correcting ocular aberrations by soft contact lenses.
  39. (1972). Corrective movements following re saccades: Type and control systems. doi
  40. (2008). Correlation between image quality and visual performance. doi
  41. (1978). Cortical magni factor predicts the photopic contrast sensitivity of peripheral vision. doi
  42. (2004). Crowding is unlike ordinary masking: Distinguishing feature integration from detection. doi
  43. (1971). Detection of grating patterns containing two spatial frequencies: a comparison of single-channel and multi-channel models. doi
  44. (1934). Diraction theory of knife-edge test and its improved form, phase contrast method. doi
  45. (1975). Discrimination of simple and complex gratings. doi
  46. (2001). Dynamics of the eye's wave aberration. doi
  47. (1997). Ecient estimation of sensory thresholds with ml-pest. doi
  48. (1986). Ecient estimation of sensory thresholds.
  49. (2007). Eect of optical correction and remaining aberrations on peripheral resolution acuity in the human eye. doi
  50. (2002). Eect of tear break-up on higher-order aberrations measured with a wavefront sensor. doi
  51. (1990). Eects of dioptric blur on snellen and grating acuity. doi
  52. (2008). Eects of higher-order aberrations on contrast acuity as a function of light level. doi
  53. (2009). Eects of monochromatic aberration on visual acuity using adaptive optics. doi
  54. (2009). Eects of monochromatic induced aberrations on visual performance measured by adaptive optics technology. doi
  55. (2001). Eects of retinal scattering in the ocular doublepass process.
  56. (2009). Eects of spherical aberration on visual acuity at dierent contrasts. doi
  57. (2007). Eects of zernike wavefront aberrations on visual acuity measured using electromagnetic adptive optics technology.
  58. (2010). Enhanced visual acuity and image perception following correction of highly aberrated eyes using an adaptive optics visual simulator. doi
  59. (1978). Estimates on probability function: A mmore viurlent pest.
  60. (2009). Evaluation of optical quality in white light from wavefront aberrations for a myopic population of human eyes. doi
  61. (1989). Evidence for edge and bar detectors in human vision. doi
  62. (1988). Eye movement control during reading: 1. the location of initial eye on words. doi
  63. (1982). Eye movement control in reading: The role of word boundaries. doi
  64. (1990). Eye movement guidance in reading: The role of parafoveal letter and space information. doi
  65. (1981). Eye movements and the perceptual span in reading. doi
  66. (2001). Eye movements during reading: Some current controversies. doi
  67. (2005). Eye movements when reading disappearing text: The importance of the word to the right of doi
  68. (1976). Eye movements while reading and searching spatially transformed text: A developmental examination. doi
  69. (2003). Eye tracking methodology: Theory and practice. doi
  70. (1959). Factors in uencing accommodation responses of the human eye. doi
  71. (2003). Fireworks in the primate retina: in vitro photodynamics reveals diverse lgn-projecting ganglion cell types. doi
  72. (1985). Frequency analysis of english usage: Lexicon and grammar.
  73. (1984). Functional characterisitics and diversity of catReferences 169 retinal ganglion cells.
  74. (1867). Helmholtz's treatise on physiological optics. doi
  75. (2006). Higher order aberrations in normal eyes measured with three dierent aberrometers.
  76. (2008). In uence of adaptive optics ocular aberration correction on visual acuity at dierent luminances and contrast polarities. doi
  77. (2007). In uence of eyelid position on wavefront aberrations. doi
  78. (2003). In vivo and in vitro repeatability os hartmann-shack aberrometry. doi
  79. (2003). Interaction between aberrations to improve of reduce visual performance. doi
  80. (1981). Is spatial phase degraded in peripheral vision and visual pathology?
  81. (1960). La transmission des contrastes par le syst eme optique de l'il et les seuilles des contrastes r etiens. Comptes Rendues de l'Acad emie des Sciences,
  82. (1971). Lateral masking for letters with unlimited viewing time. doi
  83. (1986). Lexical complexity and times in reading: eects of word frequency, verb complexity and lexical ambiguity. doi
  84. (2009). Limits of spherical blur determined with an adaptive optics system. doi
  85. (1985). Loss of spatial phase relationships in extrafoveal vision. doi
  86. (1987). Magnitude of lateral chrmatic aberration across the retina of the human eye. doi
  87. (1981). Masking of foveal and parafoveal vision during eye in reading. doi
  88. (1980). Mathematical description of the responses of simple cortical cells.
  89. (1980). Maximum likelihood estimation: The best pest. doi
  90. (1961). Measurement of the wave aberration of the human eye.
  91. (2004). Metrics of optical quality derived from wave aberrations predict visual performance. doi
  92. (1960). Modulation thresholds for sinusoidal light distributions on the retina.
  93. (1998). Monochromatic aberrations and pointspread functions of the human eye across the visual doi
  94. (2002). Monochromatic aberrations of the human eye in horizontal visual doi
  95. (1986). Motion of the eye immediately after a saccade. doi
  96. (2005). Multimedia textbooks and student learning.
  97. (1997). Multimodality image registration by maximization of mutual information. doi
  98. (2004). Neural compensation for the eye's optical aberrations. doi
  99. (2007). Night vision disturbances after successful lasik surgery.
  100. (1994). Objective measurement of wave aberrations of the human eye with the use of a hartmann-shack wave-front sensor. doi
  101. (2008). On the compensation of horizontal coma aberrations in young human eyes. doi
  102. (1801). On the mechanism of the eye. doi
  103. (2007). Operator-induced error in hartmannshack wavefront sensing: Model eye study. doi
  104. (2000). Optical aberrations of the human cornea as a function of age. doi
  105. (1965). Optical and retinal factors aecting visual resolution.
  106. (2004). Organization of visual areas in macaque and human cerebral cortex. In doi
  107. (2004). Orthographic familiarity in uences initial eye xation positions in reading. doi
  108. (2009). Palamedes: Matlab routines for analyzing psychophysical data. Available from
  109. (1986). Parafoveal word processing during eye in reading: Eects of word frequency. doi
  110. (1969). Perceptual recognition as a function of meaningfulness of the stimulus material. doi
  111. (1985). Perceptual span for letter distinctions during reading. doi
  112. (1978). Perimetry of contrast detection thresholds of moving spatial sine wave patterns. iv. the in uence of the mean retinal illuminance. doi
  113. (1978). Peripheral and cognitive components of eye guidance in reading. doi
  114. (1967). Pest: Ecient stimates on probability functions.
  115. (1984). Phase reversal discrimination. doi
  116. (2002). Phototransduction by retinal ganglion cells that set the circadian clock. doi
  117. (2007). Psychophysics of reading in normal and low vision. Lawrence Erlbaum Associates Inc.
  118. (1996). Psychophysics of reading xv: Font eects in normal and low vision.
  119. (1979). Reading without a fovea. doi
  120. (2000). Recognition threhsolds for letters with simulated dioptric blur. doi
  121. (2003). Repeatability and validity of refractive error using the bausch and lomb zywave. doi
  122. (2002). Repeatability and validity of zywave aberrometer measurements. doi
  123. (2007). Retinally stabilised cone-targeted stimulus delivery. doi
  124. (2000). Saccadic eye movements and cognition. doi
  125. (1980). Seeing: Illusion, brain and mind. doi
  126. (1987). Sensitivity loss among odd-symmetric mechanisms underlies phase anomalies in peripheral vision. doi
  127. (1964). Smoothing and dierentiation of data by simpli least squares procedures. doi
  128. (1976). Spatial factors in reading and search: The case for space. In
  129. (2000). Standards for reporting the optical aberrations of eyes. In Vision science and its applications, osa technical digest (optical society of america, doi
  130. (2002). Statistical variation of aberration structure and image quality in a normal population of healthy eyes. doi
  131. (1986). Stimuli for accommodation: Blur, chromatic aberration and size. doi
  132. (2004). Study of the tear topography dynamics using a lateral shearing interferometer. doi
  133. (1997). Supernormal vision and high-resolution retinal imaging through adaptive optics. doi
  134. (1981). Textons, the elements of texture perception, and their interactions.References 171 doi
  135. (1988). The design of a new letter chart for measuring contrast sensitivity.
  136. (1974). The eects of a visual criterion on the encoding of images. doi
  137. (1987). The in uence of colour on ctr reading performance and subjective discomfort under operational conditions. doi
  138. (1956). The in uence of visual acuity on accommodative responses of the eye. doi
  139. (1975). The perceptual span and peripheral cues in reading. doi
  140. (1953). The possibility of compensating astronomical seeing. doi
  141. (2003). The prospects for super-acuity: Limits to visualReferences 168 performance after correction of monochromatic ocular aberration. doi
  142. (2002). The role of spatial frequency channels in letter identi doi
  143. (1975). The span of the eective stimulus during a 174 in reading. doi
  144. (1994). The visual mediating letter identi doi
  145. (1935). Topography of the layer of rods and cones in the human retina. doi
  146. (1990). Topology of the near response triad. doi
  147. (2003). Validation of a clinical shack-hartmann aberrometer. doi
  148. (2008). Video eyetracker toolbox user manual [Computer software manual]. Available from
  149. (2004). Vision improvement by correcting higer-order aberrations with phase plates in normal eyes. doi
  150. (2003). Visual acuity as a function of Zernike mode and level of root mean square error. doi
  151. (2000). Visual bene of correcting higer order aberrations of the eye.
  152. (2010). Visual eect of the combined correction of spherical and longitudinal chromatic aberrations. doi
  153. (2002). Visual performance after correcting the monochromatic and chromatic aberrations of the eye. doi
  154. (2010). Visual performance with real-life tasks under adaptive-optics ocular aberration correction. doi
  155. (1969). Wavefront determination resulting from foucault test as applied to the human eye and visual instruments. In
  156. (2006). Wavefront-guided ablation: Evidence for ecacy compared to traditional ablation. doi
  157. (2005). Weak correlation between the aberrations dynamics of the human eye and the cardiopulmonary system. doi
  158. (1976). What guides a reader's eye movements? doi

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