| 11. |
- Frisén, Lars, 1939, et al.
(author)
-
Drusen in the optic nerve head. Verification by computerized tomography.
- 1978
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In: Archives of ophthalmology (Chicago, Ill. : 1960). - 0003-9950. ; 96:9, s. 1611-4
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Journal article (peer-reviewed)abstract
- Five patients with a clinical diagnosis of buried or exposed drusen of the optic nerve head were examined by computerized tomography (CT). The relative x-ray absorption within their nerve heads was significantly larger than in controls, reflecting the high calcium content of drusen. Computerized tomography, and particularly high-definition CT, therefore merits consideration in the investigation of disc swelling.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Frisén, Lars, 1939, et al.
(author)
-
Objective recognition of abnormal isopters.
- 1975
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In: Acta ophthalmologica. - 0001-639X. ; 53:3, s. 378-92
-
Journal article (peer-reviewed)abstract
- We have examined the hypothesis that normal and only normal isopters of the central visual field are elliptical, except for random deviations. Statistical methods capable of recognizing small deviations from elliptical shape have been developed. Theses methods have been devised to meet the special demands of clinical testing of visual fields and require only simple calculations. The qualities of these methods were examined by theoretical analysis, by large-scale simulations, and by experimental comparison with subjective evaluations. The new methods proved very useful in these examinations. A clinical study using a servo-equipped Goldman perimeter demonstrated that normal central isopters are elliptical enough for the proposed test characteristic to be of practical value in clinical work. The method allows an objective recognition of abnormal isopters with a high degree of sensitivity.
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| 17. |
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| 18. |
- Frisén, Lars, 1939, et al.
(author)
-
Optical and neural resolution in peripheral vision.
- 1975
-
In: Investigative ophthalmology. - 0020-9988. ; 14:7, s. 528-36
-
Journal article (peer-reviewed)abstract
- Visual acuity along the horizontal meridian in the peripheral field of vision was determined at a photopic level in two normal subjects. Two types of sinusoidally modulated, monochromatic test patterns of high contrast were used. One was produced directly on the retina by an interferometric technique. The other type was imaged on the retina by the dioptric apparatus of the eye; the resulting image suffered ordinary optical image degradation. The results from the interferometric acuity determinations represent maximal neural discrimination across the visual field. Acuity decreases monotonically toward the periphery, from about 45 cycles per degree in the fovea, to about 0.8 at 80 degrees of eccentricity in the temporal field. The decline is well described by a second-degree polynomial. Acuity for test patterns imaged by the optics of the eye was consistently lower than interferometric acuity. The difference increases toward the periphery. It is attributable to effects of optical aberrations. The discrepancy between optical and neural resolving power on oblique incidence needs to be taken into account whenever results obtained with external, extra-axial stimuli are to be analyzed in terms of retinal architecture.
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| 19. |
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| 20. |
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