Summary
Detection of broadband, aperiodic stimuli (edges) was investigated in normal observers, and in observers with abnormal visual experience which resulted in amblyopia. The spatial properties of the mechanisms used to detect an edge were investigated by a method of subthreshold addition. The method involved the determination of the threshold contrast for detecting an edge in the presence of a subthreshold line at various distances from the edge. In normal eyes, the one dimensional sensitivity profile of the edge detecting mechanism was: (1) approximately antisymmetric, (2) very localized, with sensitivity changes restricted to ±6'–8' on either side of the edge, and (3) phase dependent, showing an abrupt change in sign between ±1.5'. The sensitivity profiles of the amblyopic eyes were also approximately antisymmetric and showed the same steep rate of change from plus to minus as the fellow (nonamblyopic) eyes. However, in every case, the spatial extent of the profile was much broader than that of the nonamblyopic eyes. In normal eyes, the narrowest edge sensitivity profile was associated with the fovea; however, in two amblyopes with eccentric fixation, the narrowest edge sensitivity profile coincided with the locus of eccentric fixation. Moreover, the grating sensitivity function of the edge detecting mechanism of the amblyopic eye was similar to that of the non-amblyopic eye, but was shifted toward lower spatial frequencies. Control experiments show that these results are not accounted for on the basis of optics, eccentric fixation, or abnormal eye movements. The findings are discussed in terms of current models for the detection of aperiodic stimuli, and in the context of animal models of amblyopia.
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References
Albrecht DG, De Valois RL, Thorell LG (1980) Visual cortical neurons. Are bars or gratings the optimal stimuli? Science 207: 88–90
Bedell HE, Flom MC (1980) Monocular spatial distortion in strabismic amblyopic eyes. Invest Ophthalmol Vis Sci [Suppl] 19: 9
Beyerstein BL, Freeman RD (1977) Lateral spatial interactions in humans with abnormal visual experience. Vision Res 17: 1029–1036
Bishop PO, Coombs JS, Henry GH (1971) Interaction effects of visual contours on the discharge frequency of simple striate neurons. J Physiol (Lond) 219: 659–687
Campbell FW, Green DG (1965) Optical and retinal factors affecting visual resolution. J Physiol (Lond) 181: 576–593
Egan JE, Schulman AI, Greenberg GZ (1964) Operating characteristics determined by binary decisions and by ratings in signal detection and recognition by human observers. In: Swets JA (ed) Contemporary readings. Wiley, New York, pp 172–186
Eggers HM, Blakemore C (1978) Physiological basis of anisometropic amblyopia. Science 201: 264–267
Fankhauser F, Röhler R (1967) The physical stimulus the quality of the retinal image and foveal brightness discrimination in one amblyopic and two normal eyes. Doc Ophthalmol 23: 149–155
Flom MC, Weymouth FW, Kahneman D (1963) Visual resolution and contour interaction. J Opt Soc Am 53: 1026–1032
Flynn JT (1967) Spatial summation in amblyopia. Arch Ophthalmol 78: 470–474
Freeman RD, Bradley A (1980) Monocularly deprived humans. Nondeprived eye has supernormal vernier acuity. J Neurophysiol 43: 1645–1653
Graham N (1977) Visual detection of aperiodic spatial stimuli by probability summation among narrowband channels. Vision Res 17: 637–652
Graham N (1980) Spatial frequency of channels in human vision. Detecting edges without edge detectors. In: Harris C (ed) Visual coding and adaptability. Erlbaum, Hillsdale, pp 215–263
Green DM, Swets JA (1966) Signal detection theory and psychophysics. Wiley, New York
Grosvenor T (1957) The effects of duration and background luminance upon the brightness discrimination of an amblyope. Am J Optom 34: 639–663
Gstalder RJ, Green DG (1971) Laser interferometric acuity in amblyopia. J Pediatr Ophthalmol 8: 251–256
Guilford JP (1954) Psychometric methods. McGraw-Hill, New York
Hess RF (1977) Eye movements and grating acuity in strabismic amblyopia. Ophthalmic Res 9: 225–237
Hess RF, Howell ER (1977) The threshold contrast sensitivity function in strabismic amblyopia. Evidence for a two type classification. Vision Res 17: 1049–1056
Hess RF, Smith F (1977) Do optical aberrations contribute to visual loss in strabismic amblyopia? Am J Optom Physiol Opt 54: 627–633
Hess RF, Campbell FW, Greenhalgh T (1978) On the nature of the neural abnormality in human amblyopia. Neural aberrations and neural sensitivity loss. Pflügers Arch 377: 201–207
Hess RF, Campbell FW, Zimmern R (1980) Differences in the neural basis of human amblyopia. The effect of mean luminance. Vision Res 20: 295–306
Higgins KE, Daugman JG, Mansfield RJW (1979) Amblyopic contrast sensitivity. Role of unsteady fixation. Invest Ophthalmol Vis Sci [Suppl] 17: 202
Hines M (1976) Line spread function variation near the forea. Vision Res 16: 567–572
Hubel DH, Wiesel TN (1962) Receptive fields, binocular interaction and functional architecture in the cat's striate cortex. J Physiol (Lond) 160: 106–154
Ikeda H, Wright MJ (1976) Properties of LGN cells in kittens reared with convergent squint. A neurophysiological demonstration of amblyopia. Exp Brain Res 25: 62–77
Ikeda H, Tremain KE (1978) Amblyopia resulting from penalization. Neurophysiological studies of kittens reared with atropinization of one or both eyes. Br J Ophthalmol 62: 21–28
Ikeda H, Tremain KE (1979) Amblyopia occurs in retinal ganglion cells in cats reared with convergent squint without alternating fixation. Exp Brain Res 35: 559–582
Kulikowski JJ, King-Smith PE (1973) Spatial arrangement of line, edge and grating detectors revealed by subthreshold summation. Vision Res 13: 1455–1478
Levi DM, Harwerth RS (1977) Spatio-temporal interactions in anisometropic and strabismic amblyopia. Invest Ophthalmol Vis Sci 16: 90–95
Levi DM, Harwerth RS (1980) Contrast sensitivity in amblyopia due to stimulus deprivation. Br J Ophthalmol 64: 15–20
Levi DM, Harwerth RS, Venverloh J (1980) Spatial and temporal masking in amblyopia. Invest Ophthalmol Vis Sci [Suppl] 19: 9
Limb JO, Rubenstein CB (1977) A model of threshold vision incorporating inhomogeneity of the visual field. Vision Res 17: 571–584
Maffei L, Fiorentini A (1973) The visual cortex as a spatial frequency analyser. Vision Res 13: 1255–1268
Miller EF (1954) The nature and cause of impaired vision in the amblyopic eye of a squinter. Am J Optom 31: 615–623
Muer G, Payan M, Vola J (1968) Determination, indirect de la demension des champs receptifs retiniens de l'amblyope a moyen des cerilles de Hermann (note preliminaire). Bull Soc Belge Ophthalmol 150: 615
Pugh M (1958) Visual distortion in amblyopia. Br J Ophthalmol 42: 449–460
Rentschier I, Hilz R (1979) Abnormal orientation selectivity in both eyes of strabismic amblyopes. Exp Brain Res 137: 187–191
Sachs MB, Nachmias J, Robson JG (1971) Spatial frequency channels in human vision. J Opt Soc Am 61: 1176–1186
Schor CM, Hallmark W (1978) Slow control of eye position in strabismic amblyopia. Invest Ophthalmol Vis Sci 17: 577–581
Shapley RM (1974) Gaussian bars and rectangular bars: The influence of width and gradient on visibility. Vision Res 14: 1457–1462
Shapley RM, Tolhurst DJ (1973) Edge detectors in human vision. J Physiol (Lond) 229: 165–183
Stromeyer CF, Klein S (1974) Spatial frequency channels in human vision as asymmetric (edge) mechanisms. Vision Res 14: 1409–1420
Thomas J (1978) Normal and amblyopic contrast sensitivity functions in central and peripheral retinas. Invest Ophthalmol Vis Sci 17: 746–753
Tolhurst DJ (1972) On the possible existence of edge detector neurones in the human visual system. Vision Res 12: 797–804
Van Meeteren A, Vos JJ (1972) Resolution and contrast sensitivity at low luminances. Vision Res 12: 825–833
Wilson HR (1978) Quantitative characterization of two types of line spread function near the fovea. Vision Res 18: 971–982
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This work was supported by Research Grants from the National Eye Institute (Bethesda, Md.) R01EY01278 and R01EY01139
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Levi, D.M., Harwerth, R.S., Pass, A.F. et al. Edge sensitive mechanisms in humans with abnormal visual experience. Exp Brain Res 43, 270–280 (1981). https://doi.org/10.1007/BF00238368
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DOI: https://doi.org/10.1007/BF00238368