Distribution of Cones in Human and Monkey Retina: Individual Variability and Radial Asymmetry

Curcio, Christine A.; Sloan, Kenneth R.; Packer, Orin S.; Hendrickson, Anita E.; Kalina, Robert E.

doi:10.1126/science.3576186

Cited by 530 publications

(335 citation statements)

References 16 publications

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“…The sizes of MH's summation and 1.87 min arc, respectively. Curcio, Sloan, areas were 8 min arc for both fovea and paraPacker, Hendrickson and Kalina's (1987) results fovea. Since both observers had comparably yield center-to-center spacing for the cones of excellent acuity (Methods section), blurring due 0.48 min arc at the fovea centralis and 1.83 min to optical factors is not likely to be the reason arc at 5 deg nasal eccentricity.…”

Section: Discussionmentioning

confidence: 82%

The spread of adaptation in human foveal and parafoveal cone vision

1990

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Abstract-We investigated the spread of bleaching adaptation for human cone vision in the central fovea and at an eccentricity of 5 deg in the nasal retina. Cone thresholds measured after adaptation to a grating bleach were compared to those measured after a uniform bleach. We conclude that the fovea1 and parafoveal cone systems show excellent localization of the etfects of adaptation. For areas 2.5-S min removed from the bleach, our measurement show only small sensitivity losses amounting to between 0.10 and 0.25 log unit elevation in threshold, after taking account of optical scatter. AdaptationCones Fovea Parafovea INTRODUCIIONLight adaptation in the human retina entails a number of different mechanisms (see Hood & Finkelstein, 1986, for a review). The mechanism most commonly identified with adaptation involves the loss of sensitivity, or gain, of retinal cells to incremental stimuli as a consequence of exposure to an adapting light. Although it is generally agreed that the gain changes associated with light adaptation occur early in retinal processing, there is still ambiguity about the anatomical sites of action. In the rod system the primary gain changes do not seem to occur in the receptors themselves (Baylor, Nunn & Schnapf, 1984), but at a site where signals from many rods converge (Rushton & Westheimer, 1962). Rushton (1965) pointed out that the scotopic increment threshold begins to rise at a level where individual rods receive, on the average, less than one quantum per second, suggesting that ~nsitivity is controlled by the pooled signals from many rods. This conclusion is supported by physiological evidence for spatial summation of the effects of adaptation as measured in the rod-driven activity of ganglion cells in the cat (e.g. Cleland & Enroth-Cugell, 1968; Enroth-Cugell & Shapley, 1973). Spatial summation is also observed in the loss of sensitivity associated with very bright bleaching *The expmiments reported here were performed while the authors were at the Uni~~ity of California, San Diego.lights (Rushton $ Westheimer, 1962; Andrews &c Butcher, 1981;Barlow & Andrews, 1973; Bonds & Enroth-Cugell, 1979; MacLeod, Chen & Crognale, 1989;Cicerone & Hayhoe, 1990). It is less clear whether there is a similar kind of spatial summation of adaptation in the cone system. Based on a number of lines of evidence, it has commonly been thought that the primary gain adjustment in response to light occurs in the cone photoreceptors themselves (e.g. Shapley & Enroth-Cugell, 1984). The rr mechanisms isolated by Stiles' chromatic adaptation experiments closely resemble the photopigment spectral sensitivities (Pugh & Sigel, 1978), indicating, to a first approximation, that the different cone types adapt independently and much of adaptation occurs in the cones themselves. More clear cut evidence for receptoral adaptation, at least for bleaching lights, is provided by Wi~ams and MacLeod (1979), who found that bleaching exposures gave inde~ndent sensitivity losses in long-and middle-wavelength-sensitive cone sys...

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Section: Discussionmentioning

confidence: 82%

The spread of adaptation in human foveal and parafoveal cone vision

1990

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“…Scleral thinning is greatest at the posterior pole of the eye, the anatomical region of greatest retinal photoreceptor density and vital to detailed visual discrimination (5,6). In some individuals, the thinned posterior sclera precipitates local ectasic change or staphyloma (7,8).…”

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confidence: 99%

Collagen Gene Expression and the Altered Accumulation of Scleral Collagen during the Development of High Myopia

Gentle

Liu

Martin

et al. 2003

Journal of Biological Chemistry

171

120

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The development of high myopia is associated with reduced scleral collagen accumulation, scleral thinning, and loss of scleral tissue, in both humans and animal models. Reduced collagen fibril diameter is also observed in the sclera of eyes with high myopia. The present study investigated aspects of scleral collagen synthesis and degradation, in a mammalian model of high myopia, to elucidate the factors underlying scleral changes. General synthesis and degradation of scleral collagen was investigated in monocularly deprived tree shrews, through the in vivo administration of [ 3 H]proline and subsequent assay of scleral tissue for [ 3 H]collagen. In addition, PCR enriched cDNA, produced from tree shrew scleral mRNA, was used to synthesize probes for hybridization to custom gene arrays consisting of partial sequences for 11 collagen subtypes. Finally, realtime reverse transcriptase-PCR was employed to investigate collagen type I, III, and V mRNA expression in the sclera of myopic, contralateral control, and normal tree shrew eyes. Scleral [ 3 H]proline incorporation was reduced at the posterior pole of myopic eyes following 5 days of monocular deprivation (؊36 ؎ 4%), whereas [ 3 H]proline content was similar in treated and control eyes before myopia induction (؊1 ؎ 8%) but was reduced in myopic eyes following 5 (؊8 ؎ 2%), 12 (؊15 ؎ 4%), and 24 (؊10 ؎ 4%) days of myopia induction. The majority of the collagens investigated were found to be expressed in the sclera, with 11 subtypes being identified. Collagen type I mRNA expression was reduced in the sclera of myopic eyes (؊20 ؎ 7%), however, collagen type III (؉2 ؎ 9%) and type V (؊1 ؎ 6%) expression was unchanged relative to control, resulting in a net increase in the ratio of expression of collagen type III/type I and collagen type V/type I (22 and 25%, respectively). These results show that reduced scleral collagen accumulation in myopic eyes is a result of both decreased collagen synthesis and accelerated collagen degradation. Furthermore, changes in collagen synthesis are driven by reduced type I collagen production. Short term increases in the ratio of newly synthesized collagen type III/type I and type V/type I are likely to be important in the increasing frequency of small diameter scleral collagen fibrils observed in high myopia and may be important in the subsequent development of posterior staphyloma in humans with pathological myopia.The refractive power of the eye is correlated with ocular axial length and it is well established that myopia is caused by increased axial eye size (1). Studies, in humans and animal models, have shown how this increased axial length is predominantly a consequence of increased vitreous chamber depth, rather than marked changes in any other ocular component parameter such as anterior chamber depth or lens thickness (2, 3). The prevalence of human high myopia (usually defined as eyes with Ͼ6 dioptres (D) of myopia, or Ͼ26 mm in length) is ϳ2% in the general population (1) and it is well documented that individuals with high my...

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“…This distribution of response density approximately corresponds to the anatomical occurrence of cone distribution of the posterior pole. [18][19][20]31 The control group in this study was not age matched, which could have an influence on the results because it is known that an age-related effect exists. Other studies showed a decrease of amplitudes in older patients.…”

Section: Discussionmentioning

confidence: 99%

“…The visual stimulus, consisting of a matrix of hexagonal areas flickering concurrently according to a short m-sequence, is displayed directly onto the retina covering a visual angle of about 121 or a diameter of 241, respectively ( Figure 2). 18,19 It consists of a matrix of 61 hexagonal elements and is generated by a helium-neon laser (632.8 nm) modulated via an acousto-optic modulator. The matrix has been presented according to a scaling factor 1:4, so that the hexagonal size would be accordingly scaled with eccentricity in order to evoke focal responses of approximately the same amplitude per stimulus element in the response arrays of normal individuals.…”

Section: Methodsmentioning

confidence: 99%

Scanning laser ophthalmoscope-evoked multifocal ERG (SLO-mfERG) in patients with macular holes and normal individuals

Rudolph

Kalpadakis

Bechmann

et al. 2003

Eye

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Aims A scanning laser ophthalmoscope (SLO) has been used for multifocal electroretinography (mf ERG) measurements under simultaneous fundus monitoring. The aim of this study was to prove if the SLOmfERG measurement reflects reliably the clinically registered underlying disease, and to demonstrate the importance of its main advantage, fixation monitoring. Methods In all, 10 patients with macular hole stage II/III were included in the study, and 19 normal individuals served as the control group. The mf ERG device was combined with an SLO, which was used both as a stimulus and trigger unit as well as a fundusmonitoring system. Monitoring of the fundus was guaranteed by an infrared laser (780 nm). The stimulus matrix consisted of 61 hexagonal elements, covering 241 of the posterior pole. We examined both, patients with macular holes and healthy individuals. Results Compared to normal controls, patients with a macular hole (Gass stage III) showed a significant decrease in response density in the centre of the stimulus array, which correlated well with the morphological alteration observed by clinical examination. However, variation of response density of the central hexagonal area has been proved to be high. Conclusions SLO-mfERG is a feasible and reliable new technique to investigate macular function under simultaneous fundus control. The main advantage is that control of fixation can be used in order to obtain more reliable results that correlate well with visible fundus abnormalities such as in patients with macular holes. However, further investigations have to be performed in order to overcome sufficiently the problem of fixation instability.

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Distribution of Cones in Human and Monkey Retina: Individual Variability and Radial Asymmetry

Cited by 530 publications

References 16 publications

The spread of adaptation in human foveal and parafoveal cone vision

The spread of adaptation in human foveal and parafoveal cone vision

Collagen Gene Expression and the Altered Accumulation of Scleral Collagen during the Development of High Myopia

Scanning laser ophthalmoscope-evoked multifocal ERG (SLO-mfERG) in patients with macular holes and normal individuals

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