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- Sjöstrand, Johan, 1936, et al.
(författare)
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Morphometric study of the displacement of retinal ganglion cells subserving cones within the human fovea
- 1999
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Ingår i: Graefes Archive for Clinical and Experimental Ophthalmology. - 0721-832X. ; 237:12, s. 1014-1023
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Tidskriftsartikel (refereegranskat)abstract
- Background: A study was carried out to measure the displacement of retinal ganglion cells subserving the cones within the human fovea. Methods: Four human retinas were examined along the nasal or vertical hemi-meridians. Total displacement was estimated by adding the displacement due to fibres of Henle and bipolar cells, measured as the lateral extension of the Henle fibres and of the obliquely running fibre bundles within the inner nuclear layer, respectively. Results: At the foveal border (0.5-0.8 mm or 1.8-2.9 deg eccentricity) the mean offset due to fibres of Henle and mean total lateral displacement was at a maximum of 0.32+/-0.03 mm and 0.37+/-0.03 mm, respectively. A steep decrease of displacement was found outside the foveal border out to an eccentricity of 2.0-2.5 mm. We were able to plot displacement along the vertical meridian in relation to eccentricity with good correlation between three eyes. The data were used to establish different mathematical functions describing the relation between eccentricity and displacement. These functions were applied to previously presented data on densities of retinal ganglion cells and cones. Conclusions: The present estimates of displacement within the human central fovea offer the possibility of analysis of quantitative relations between cones and retinal ganglion cells. Our data provide predictive guidance by establishing that vitreo-retinal procedures causing damage to retinal ganglion cells up to 1 mm from the foveal centre could have implications for loss of information generated within the fovea.
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| 2. |
- Sjöstrand, Johan, 1936, et al.
(författare)
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Quantitative estimations of foveal and extra-foveal retinal circuitry in humans
- 1999
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Ingår i: Vision Research. - 0042-6989. ; 39:18, s. 2987-2998
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Tidskriftsartikel (refereegranskat)abstract
- For an understanding of the basis for psychophysical measurement of visual resolution, quantitative morphological studies of retinal neuronal architecture are needed. Here we report on cell densities and retinal ganglion cell:cone ratio (RGC:C) from the foveal border to the peripheral retina (34 degrees eccentricity). Quantitative estimates of RGC and C densities were made using a modified disector method in three vertically sectioned human retinae and were adjusted for RGC displacement. In agreement with our previous data on humans, we found an RGC:C ratio close to 3 at 2-3 degrees eccentricity. Outside the foveal border, the ratio declined to 1.0 at 7.5 degrees eccentricity and to 0.5 at eccentricities larger than 19 degrees. Center-to-center separation of C and RGC in addition to center-to-center separation of estimated 'receptive fields' was calculated at corresponding locations along the superior and inferior hemimeridians. The center-to-center separation of estimated 'receptive fields' was found to be more closely related to resolution thresholds from the fovea to 19 degrees eccentricity than was the separation of RGC and C. On the basis of these quantitative estimates, models for neural circuitry involved in central and peripheral spatial vision can be discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.
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