| 1. |
- Agardh, Carl-David, et al.
(author)
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Optic disc swelling in an insulin-dependent diabetic. A result of drastic improvement of glucose control?
- 1988
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In: Acta Ophthalmologica. - 0001-639X. ; 66:2, s. 206-209
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Journal article (peer-reviewed)abstract
- Rapid improvement of glucose control in diabetics may cause a transient progression of ischemic retinopathy. We report a transient bilateral acute asymptomatic optic disc swelling associated with rapid improvement of metabolic control in a male Type I diabetic. It is d, suggested that the optic disc swelling could be caused n of by a rapid near-normal normalization of the blood glucose.
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| 2. |
- Agardh, Carl-David, et al.
(author)
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Platelet aggregation in type I diabetics with and without proliferative retinopathy
- 1987
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In: Acta Ophthalmologica. - 0001-639X. ; 65:3, s. 358-362
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Journal article (peer-reviewed)abstract
- The cause of retinopathy in diabetes mellitus is unknown. Among factors suggested to be involved in the development of retinopathy is altered platelet function. In the present study, platelet aggregation was measured in vitro after stimulation with adenosine diphosphate (ADP) and collagen in patients with and without proliferative retinopathy. The results show that patients with proliferative retinopathy have an increased platelet aggregation in vitro after stimulation with collagen and ADP. However, the increased platelet aggregation was also found to be correlated to the duration of diabetes. Thus, the present study does not support the opinion that abnormal platelet function can be regarded as a primary cause of diabetic retinopathy. Increased platelet aggregation seems to be coupled to the duration of diabetes and to still unknown factors developing with prolonged duration of the disease.
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| 3. |
- Agardh, Elisabet, et al.
(author)
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Normal eyes in type 1 diabetics stay normal after one year of treatment with continuous subcutaneous insulin pump
- 1986
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In: Acta Ophthalmologica. - 0001-639X. ; 64:5, s. 530-532
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Journal article (peer-reviewed)abstract
- Seven patients with type 1 diabetes mellitus were restored to near normoglycaemia by treatment with continuous subcutaneous insulin infusion pumps (CSII). The patients were examined with ophthalmoscopy, fundus photography and fluorescein angiography before and one year after the start of CSII treatment. In addition, ophthalmoscopy was performed after 6 months of treatment. All 14 eyes were normal prior to the CSII treatment and none had developed any signs of retinopathy after 6 months or 1 year. It is concluded that metabolic control can be near normalized with CSII treatment without any risk for development of diabetic microangiopathy in type 1 diabetics with normal eyes.
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| 4. |
- Airaksinen, P J, et al.
(author)
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Visual field and retinal nerve fibre layer in early glaucoma after optic disc haemorrhage
- 1983
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In: Acta Ophthalmologica. - : Wiley. - 0001-639X .- 1755-375X. ; 61:2, s. 94-186
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Journal article (peer-reviewed)abstract
- Computerized visual field testing with the Competer automatic perimeter including automatic profile perimetry revealed early glaucomatous field loss in 9 of 10 eyes with photographically demonstrable retinal nerve fibre layer (RNFL) defects after optic disc haemorrhages despite the fact than conventional routine perimetry had failed to do so. In 7 of these cases the Competer central pattern test was abnormal; in 2 cases field defects could be shown only when automatic high-resolution static profile perimetry was performed and directed according to the information present in wide-angle RNFL photographs. A field defect was also found in one of five eyes with no photographic RNFL changes. Visual field defects seem to occur in a higher proportion of cases with RNFL defects than was previously thought, but they can be very subtle and hard to find. There are, however, cases where in spite of the presence of an indisputable RNFL defect no visual field defects can be shown even with painstaking technique and conversely field defects may be present without RNFL defects. Automatic perimetry and RNFL photography complement each other in early detection and quantitation of glaucomatous damage.
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| 5. |
- Alm, Albert
(author)
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Effects of norepinephrine, angiotensin, dihydroergotamine, papaverine, isoproterenol, histamine, nicotinic acid, and xanthinol nicotinate on retinal oxygen tension in cats
- 1972
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In: Acta Ophthalmologica. - : Wiley. - 0001-639X .- 1755-375X. ; 50:5, s. 707-719
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Journal article (peer-reviewed)abstract
- The oxygen tension in the vitreous body close to the retina, PvrO2, was determined continuously in cats. The effects on PvrO2 of intraarterial injections of various vasoactive drugs were determined. The vasoconstrictors norepinephrine, angiotensin and dihydroergotamine did not change PvrO2 in five cats. The same result was obtained with the vasodilators isoproterenol, histamine and xanthinol nicotinate in five cats, and with nicotinic acid in six cats, while papaverine invariably increased PvrO2 in seven cats when injected intraarterially and in two cats when injected intravenously. It is suggested that the ability to penetrate the blood-retinal barrier may play an important role in determining the effect of vaso-active drugs on retinal blood flow.
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| 6. |
- Asman, P, et al.
(author)
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Spatial analyses of glaucomatous visual fields; a comparison with traditional visual field indices
- 1992
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In: Acta Ophthalmologica. - 0001-639X. ; 70:5, s. 86-679
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Journal article (peer-reviewed)abstract
- Interpretation of numeric automated threshold visual field results is often difficult. A large amount of data is obtained for every single field tested. Various approaches to summarize this data have been suggested, most commonly the mean and standard deviation of departures from age-corrected normal threshold values. These visual field indices differ substantially from subjective field interpretation where spatial relationships are important. We have previously devised two methods for automated field interpretation which take spatial information into account--regional up-down comparisons and arcuate cluster analysis. We now studied the merits of using these new spatial methods and compared them to traditional visual field indices for discrimination between normal and glaucomatous field results. Central static 30 degree field results in 101 eyes of 101 normal subjects and 101 eyes of 101 patients with glaucoma were discriminated using logistic regression analysis. The best field classification was obtained with a spatial visual field model combining up-down differences and arcuate clusters. The advantages of the spatial model were confirmed in an independent material of 163 eyes of 163 normal subjects and 76 eyes of 76 patients with glaucoma where eyes with large field defects had been removed. In this material the spatial model gave 87% sensitivity and 83% specificity while the best non-spatial model gave 82% sensitivity and 80% specificity. Visual field interpretation in glaucoma may be significantly enhanced if detection is focused on circumscribed field loss rather than on averages of differential light sensitivities and similar indices which do not take spatial relationships into consideration.
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| 7. |
- Asman, P, et al.
(author)
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Weighting according to location in computer-assisted glaucoma visual field analysis
- 1992
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In: Acta Ophthalmologica. - : Wiley. - 0001-639X .- 1755-375X. ; 70:5, s. 8-671
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Journal article (peer-reviewed)abstract
- In recent years several aids for automated interpretation of visual field data have been suggested. We believed that incorporation of thorough knowledge of normal visual field variability would allow improvements in the performance of such aids since more attention would be paid to field results in areas with low physiological variability. Two visual field models for classification of fields in glaucoma based on comparisons of sensitivity values in the upper and lower hemifields and on analysis of test point clusters with diminished sensitivity were compared. Both models were constructed using logistic regression analysis in 101 normal eyes and 101 eyes with glaucoma. The first, more traditional model assumed Gaussian distributions of deviations from age-corrected normal thresholds and constant variability across the field (non-weighted model). The second model took into account empirically determined variability of pointwise threshold results and of cluster volumes in various visual field regions (weighted model). The two models were subsequently tested on an independent material of 163 normal eyes and 76 eyes with glaucoma. The weighted model gave significantly better classification of the fields in both materials. Accounting for physiological threshold variability can offer significant advantages in the construction of perimetric analysis aids for detection of glaucoma.
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| 8. |
- Beckman, Claes, 1962-
(author)
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Comparison of three methods of evaluating glare.
- 1992
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In: Acta ophthalmologica. - 0001-639X. ; 70:1, s. 53-9
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Journal article (peer-reviewed)abstract
- A Humphrey Automatic Refractor Model 570 was used to measure the impairment of visual acuity for low contrast optotypes as a result of glare for normal subjects and for subjects with cataracts. This was compared with a direct measure of intraocular light scatter as measured by a compensating technique and with a subjective assessment of glare determined by a questionnaire. Only a weak correlation (r = 0.28) was found between the decrease in low contrast letter acuity and intraocular light scatter. The subjective assessment of glare sensitivity was not correlated with the decrease in low contrast letter acuity, but correlated to some extent (r = 0.55) with the measurement of intraocular light scatter.
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| 9. |
- Beckman, Claes, 1962-
(author)
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Glare and contrast sensitivity before and after Nd : YAG laser capsulotomy.
- 1994
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In: Acta ophthalmologica. - 0001-639X. ; 72:1, s. 27-32
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Journal article (peer-reviewed)abstract
- The benefits of Nd:YAG laser capsulotomy on visual performance were evaluated in 13 patients with after-cataract following extracapsular cataract extraction. Besides clinical evaluation we measured: visual acuity, letter contrast sensitivity with and without the presence of a circular glare source (glare angle: 8 degrees). Finally, the patients were asked to evaluate their subjective glare problems. In all patients, visual acuity had decreased markedly compared to measurements 2 months after cataract surgery. Before capsulotomy we observed impaired letter contrast sensitivity and increased intraocular light scatter compared to normals. Following capsulotomy, VA and contrast sensitivity both improved by a factor of 2. The subjective glare problems diminished, although most patients showed minor decreases in intraocular light scatter. The limited glare induced loss of letter contrast sensitivity, present before capsulotomy, remained after treatment. Our study indicates that after-cataract impairs resolution and contrast sensitivity without necessarily causing a marked increase in light scatter as measured at a large angle.
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| 10. |
- Beckman, Claes, 1962-
(author)
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Glare measurements before and after cataract surgery.
- 1993
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In: Acta ophthalmologica. - 0001-639X. ; 71:4, s. 471-6
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Journal article (peer-reviewed)abstract
- The efficacy of cataract surgery in improving visual performance was evaluated in 10 patients by measuring changes in intraocular light scatter, contrast sensitivity and glare induced visual loss. Two different methods were used to estimate these functions before and after cataract extraction with implantation of a monofocal posterior intraocular lens. By one method intraocular light scattering was assessed. By the other, letter contrast sensitivity and glare induced visual loss were determined. Preoperatively most patients had various glare problems, glare induced visual loss and increased intraocular light scatter. Following surgery the letter contrast sensitivity increased by a factor of 3 or more (mean 4.3). The glare problems diminished or disappeared after surgery, although several patients still had increased intraocular light scattering and glare induced visual loss compared to normals. Postoperatively the contrast sensitivity both with and without glare had increased to a level where the glare induced visual loss did not create any visual problems.
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| 11. |
- Dyster-Aas, K, et al.
(author)
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Computerized visual field screening in the management of patients with ocular hypertension
- 1980
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In: Acta Ophthalmologica. - : Wiley. - 0001-639X .- 1755-375X. ; 58:6, s. 918-928
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Journal article (peer-reviewed)abstract
- Visual field testing which the Computer fully automatic computerized perimeter (Heijl & Krakau 1975) employing a supra-liminal screening test procedure was used in a material of 1013 eyes with ocular hypertension in which earlier routine perimetry (kinetic and static) on the Goldmann perimeter had yielded a normal result. The automatic screening was repeated if positive, and manual control perimetry was used in order to confirm or reject identified field defects. This procedure revealed field defects that could be confirmed at both automatic and manual perimetry in 3.6% of the eyes. In the control group the incidence of field defects found at manual perimetry during the same time interval was calculated at 0.4%. Thus automatic screening revealed several times more field defects than manual routine perimetry. Eyes in which repeated automatic screening had indicated defects which manual control perimetry failed to confirm, showed a high percentage of field loss at later follow-up. The results are discussed, and the conclusion is drawn that automatic screening is clearly superior to manual routine perimetry used at present. The most practical solution in many eye departments would be to use a computerized perimeter for the visual field screening of glaucoma suspects.
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| 12. |
- Frisén, Lars, 1939, et al.
(author)
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A simple relationship between the probability distribution of visual acuity and the density of retinal output channels.
- 1976
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In: Acta ophthalmologica. - 0001-639X. ; 54:4, s. 437-44
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Journal article (peer-reviewed)abstract
- Throughout the retina, the parameters of the probability distribution of visual acuity for monochromatic interference fringes are closely proportional to the number of retinal ganglion cells per degree of visual angle. There are no simple relationships to receptor spatial frequencies. These findings suggest that neuro-retinal acuity is determined principally by the spatial frequency of neural output channels.
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| 13. |
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| 14. |
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| 15. |
- Frisén, Lars, 1939
(author)
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High-pass resolution perimetry and age-related loss of visual pathway neurons.
- 1991
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In: Acta ophthalmologica. - 0001-639X. ; 69:4, s. 511-5
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Journal article (peer-reviewed)abstract
- The normal, age-related decline of results of high-pass resolution perimetry (HRP) predicts a loss of approximately 9,000 retino-cortical neural channels per year of age, or about 1 channel each hour. Previously published counts of numbers of neurons in the optic nerve indicate a loss of approximately 5,000 neurons per year. The HRP results can be accounted for by postulating that neurons are lost at the same rate also in the geniculo-striate visual pathway.
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| 16. |
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| 17. |
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| 18. |
- Frisén, Lars, 1939, et al.
(author)
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Objective recognition of abnormal isopters.
- 1975
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In: Acta ophthalmologica. - 0001-639X. ; 53:3, s. 378-92
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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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| 19. |
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| 20. |
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| 21. |
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| 22. |
- Frisén, Lars, 1939, et al.
(author)
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Properties of high-pass resolution perimetry targets.
- 1993
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In: Acta ophthalmologica. - 0001-639X. ; 71:3, s. 320-6
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Journal article (peer-reviewed)abstract
- Relationships between high-pass resolution perimetry ring targets and conventional perimetry and acuity targets were explored by optical analytical techniques and by comparative measurements in normal humans. High-pass resolution and acuity targets produced closely proportional resolution measurements, showing that the critical ring detail is the width of the bright core. High-pass resolution and conventional perimetry thresholds were not equally well correlated. From a purely optical point of view, high-pass resolution targets appeared to lose somewhat more contrast on defocusing. On the other hand, high-pass resolution appears to show less variability in practical, clinical use.
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| 23. |
- Frisén, Lars, 1939, et al.
(author)
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Relationship between perimetric eccentricity and retinal locus in a human eye. Comparison with theoretical calculations.
- 1977
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In: Acta ophthalmologica. - 0001-639X. ; 55:1, s. 63-8
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Journal article (peer-reviewed)abstract
- A blind but grossly normal eye was removed because of severe pain. With the patient's consent, photo-coagulation markers were placed along the horizontal meridian of the retina prior to surgery. The angular coordinates in visual space of the markers were determined by an ophthalmoscopic procedure. The loci of the markers were also determined in a flat preparation following enucleation. The relationship between retinal arc and perimetric eccentricity was found to be approximately linear up to at least 50 degrees. Our findings validate earlier theoretical calculations within this range.
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| 24. |
- Heijl, A, et al.
(author)
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An automatic static perimeter, design and pilot study
- 1975
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In: Acta Ophthalmologica. - : Wiley. - 0001-639X .- 1755-375X. ; 53:3, s. 293-310
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Journal article (peer-reviewed)abstract
- An instrument for automatic static perimetry at 14 points across a meridian was constructed and used in a pilot study. The machine was controlled by a computer and the subjects responded to the light stimuli by pressing one of two push-buttons. Most people investigated readily understood the rules at testing. "Blunders" made by the subject were, however, so common, that allowance had to be made in the test programme for a number of mistakes. The test stimuli should be exposed in random order. When the zone of uncertain seeing is wide - this occurs especially in untrained subjects - a simple test logic gives a fairly large variation. An improvement in reproducibility is then obtained by applying a more complicated logic, though at the cost of an increased duration of the test session.
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| 25. |
- Heijl, A
(author)
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Computer test logics for automatic perimetry
- 1977
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In: Acta Ophthalmologica. - : Wiley. - 0001-639X .- 1755-375X. ; 55:5, s. 53-837
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Journal article (peer-reviewed)abstract
- Using an automatic computerized perimeter developed by Heijl & Krakau (1975b) three different perimetric test logics, one simple (I) and two more complicated and time-consuming (II & III) were investigated in practical experiments on healthy normal test subjects and patients and in computer simulated tests. The patients either had a verified diagnosis of glaucoma or glaucoma was suspected. The best consistency in measured thresholds was obtained with test logic II, in which an averaging procedure is used. The variation of the results was larger in pathological than in normal visual fields. All test logics investigated readily detected the pathological field defects, but blind spots could easier pass unrecognized with the simplest logic than with the other two logics. The conclusion is drawn that a simple test logic can be used for perimetry in glaucoma suspects if no visual field defect has previously been documented. For the follow-up of pathological fields a fairly complicated test logic, e.g. using averaging, is preferable.
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