| 1. |
- Blomsterwall, Elisabeth, et al.
(författare)
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Postural function and subjective eye level in patients with idiopathic normal pressure hydrocephalus.
- 2011
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Ingår i: Journal of neurology. - : Springer Science and Business Media LLC. - 1432-1459 .- 0340-5354. ; 258:7, s. 1341-6
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Tidskriftsartikel (refereegranskat)abstract
- Disturbance of posture is a frequent indication of idiopathic normal pressure hydrocephalus (iNPH) and is characterised by an increased sway in the frontal and sagittal planes. Further, iNPH patients with increased backward sway are known to have a defective perception of the subjective visual vertical (SVV), with the upper portion of an articulated rod tilted towards themselves. The objective of the present study was to compare subjective eye level (SEL) with actual eye level (EL) and compare this data with SVV and postural function. Twenty iNPH patients and ten normal controls estimated SEL by placing an adjustable horizontal line at EL. Sway pattern and SVV were also examined as previously described. The patients presented larger errors on downward as compared to upward line adjustments; all patients also presented a SVV tilted towards them. The patients swayed more in the sagittal than in the frontal plane at a higher speed than the normal controls, and they were relatively less helped by their vision. This is in accordance with the tendency to fall backwards seen in many iNPH patients. iNPH patients have a tendency to place SEL higher than EL and this, together with examination of SVV and sway pattern, suggests defective internal processing of gravicentric information.
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| 2. |
- Frisén, Lars, 1939
(författare)
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Deviations of the visual upright in three dimensions in disorders of the brainstem: a clinical exploration.
- 2010
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 133:12, s. 3541-3551
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Tidskriftsartikel (refereegranskat)abstract
- Deviations of the subjective visual vertical in the roll or fronto-parallel plane occur commonly in disorders of the brainstem and have been extensively explored. In contrast, little is known about deviations in other directions. The present retrospective study focused on deviations in the pitch (sagittal) direction in 176 patients with a wide variety of disorders. The test task was to set a self-illuminated rod in the apparent upright position, in total darkness. Abnormal results (outside±4°) were recorded in 58% of the subjects. Negative (top backward) deviations were the most common, particularly with mass lesions in the pineal region, obstructive hydrocephalus, cerebellar lesions and crowding at the craniocervical junction. Positive and negative deviations were about equally common with focal intra-axial lesions. Negative deviations appeared related to dorsal locations of lesions and vice versa. Normal pressure hydrocephalus, Parkinson's disease and progressive supranuclear palsy were associated with smaller deviations, without a clear directional preponderance, and a larger individual variability. Most subjects lacked overt clinical corollaries. The most common ocular signs were aqueduct syndromes (n=17) and ocular tilt reactions (n=12), which were associated with deviations in 47 and 92% of instances, respectively. Subjective corollaries of deviation were never reported, not even by those subjects who showed a dramatic improvement upon resolution of the underlying condition. Deviations were also assessed in roll in a subgroup of 40 patients with focal lesions. Thirty subjects returned abnormal results: 13% in roll, 47% in pitch and 40% in pitch and roll. The direction of roll deviation appeared primarily related to laterality, with clockwise deviations with right-sided lesions and vice versa. All subjects with ocular tilt reactions had combined pitch and roll deviations, implying a common neural substrate. Correlation analyses, geometrical modelling and experimental self-observations indicated that deviations in pitch were attributable to cyclotorsional asymmetries between the eyes. The frequent co-existence of abnormal pitch and roll results implies that the true axis of deviation in focal brainstem disorders commonly falls outside traditional reference planes. The term 'visual upright in three dimensions' is suggested to identify unrestricted measurements, preserving the established term 'visual vertical' for measurements confined to the roll plane. Assessment of the visual upright in three dimensions provides a new, quantitative angle on brainstem disorders. The test appears useful for identifying a ubiquitous yet clinically silent feature of brainstem disease and also for monitoring the evolution of underlying conditions. More detailed explorations appear well motivated.
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| 3. |
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| 4. |
- Frisén, Lars, 1939
(författare)
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Identification of functional visual field loss by automated static perimetry
- 2014
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Ingår i: Acta Ophthalmologica. - : Wiley. - 1755-375X. ; 92:8, s. 805-809
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Tidskriftsartikel (refereegranskat)abstract
- PurposeDiagnosis of functional visual field loss, that is, field loss lacking objective corollaries, has long relied on kinetic visual field examinations using tangent screens or manual perimeters. The modern dominance of automated static perimeters requires the formulation of new diagnostic criteria. MethodsRetrospective review of automated perimetry records from 36 subjects meeting clinical and tangent screen criteria for functional visual field loss. Thirty-three normal eyes and 57 eyes with true lesions, including optic nerve compression, glaucoma, anterior ischaemic optic neuropathy and vigabatrin toxicity, served as controls. ResultsStandard automated perimetry statistics were unable to reliably discriminate organic versus non-organic visual field loss. Subjective evaluation of perimetric maps indicated that functional fields generally could be identified by the presence of severe and irregular contractions and depressions that did not conform to the visual system's neuro-architecture. Further, functional fields generally presented one or more isolated threshold spikes', that is, isolated locations showing much better than average sensitivity. On repeated examinations, threshold spikes always changed locations. Visual evaluation for spikes proved superior to an objective computational algorithm. Fairly reliable objective discrimination of functional fields could be achieved by point-wise correlations of repeated examinations: median intertest correlation coefficients equalled 0.47 compared with 0.81 for true lesions. ConclusionFunctional visual loss can be identified by automated static perimetry. Useful criteria include severe and irregular contractions and depressions, the presence of isolated threshold spikes and poor intertest correlations.
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| 5. |
- Frisén, Lars, 1939
(författare)
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Ocular torsions and the subjective visual vertical with central vestibulo-ocular system lesions: independence disproved
- 2012
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Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314. ; 126:3, s. 205-209
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Torsions of the eyes and deviations of the subjective visual vertical in roll occur regularly with disorders of the central vestibulo-ocular system. Although nearly universally coexisting, torsions and deviation have been held to be more or less independent of each other. Materials and methods: Angles of torsion were determined from fundus photographs in 55 subjects representing a variety of acute, focal, brainstem or cerebellar lesions. Measured torsions were contrasted with quantitative measurements of the subjective visual vertical. Results: Torsions and deviations proved to be directly proportional, with a direction coefficient close to unity, and were strongly correlated (r = 0.86). Conclusions: Torsions and deviations are strongly dependent. This result should allow the generation of a more transparent pathophysiological model. From a practical point of view, measurements of deviation appeared more robust than those of torsion.
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| 6. |
- Frisén, Lars, 1939
(författare)
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Performance of a Rapid Rarebit Central-Vision Test with Optic Neuropathies
- 2012
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Ingår i: Optometry and Vision Science. - 1040-5488. ; 89:8, s. 1192-1195
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. Rarebit vision tests probe for gaps in the neuro-retinal receptive field matrix, using bright micro dots on a dark background. Previous reports have found central-vision rarebit tests useful for macular lesions. Their performance with lesions of the anterior visual pathways has not been explored. Methods. Twenty-two subjects with optic nerve lesions of light to moderate severities were examined with a novel, self-contained rarebit test. Outcomes were contrasted with results of high-pass resolution perimetry and a threshold letter acuity test. Results. The results of the three tests differed significantly from those of normal control subjects. There were no meaningful inter-test correlations. Analysis of receiver-operating characteristic curves revealed closely similar powers of discrimination. Mean test time for the rarebit test was 1: 42 min, and for the other tests, it was approximately 5 min each. Conclusions. The rarebit test appeared highly capable of detecting optic neuropathies and chiasmal lesions. Its simplicity and short test duration indicate a useful role in screening settings. (Optom Vis Sci 2012; 89:1192-1195)
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| 7. |
- Frisén, Lars, 1939
(författare)
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Rapid Assessment of Neurovisual Integrity Using Multiple Rarebits
- 2013
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Ingår i: Ophthalmology. - : Elsevier BV. - 0161-6420. ; 120:9, s. 1756-1760
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Rapid assessments of vision commonly rely on visual acuity testing alone. Although well suited for uncovering optical defects, visual acuity tests may fail to detect dysfunction of the neural substrate. There is a need for a rapid companion test sensitive to neural damage. Participants and Controls: Forty-seven patients with optic nerve or visual pathway lesions of low to moderate severities and 30 normal subjects. Methods: A new computer-based quick test of neurovisual integrity was developed using segmented digits defined by rarebits, that is, receptive field-size bright dots briefly presented on a dark background. Main Outcome Measures: The test variable was the number of rarebits per segment; digit size was fixed. The test task was to call out verbally all digits that were seen during an 8-second presentation sequence. Test outcomes were contrasted with the results of an optotype acuity test and automated perimetry. Results: All subjects easily grasped the test task. The normal subjects read, on average, 5.6 (+/- 0.5 standard deviation) of the 6 digits contained in the test sequence, whereas the patients averaged 3.3 +/- 1.8 digits. The numbers of digits read correlated modestly with the acuity and perimetry results. Analysis of receiver operating characteristic curves indicated that the multiple rarebit test provided the best discrimination. Conclusions: The multiple rarebit test seemed to be highly capable of detecting neurovisual dysfunction. Its simplicity and uniquely short duration indicate a useful role in screening settings. The test is available free on the Internet.
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| 8. |
- Frisén, Lars, 1939
(författare)
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Scope of super-resolution in central vision.
- 2010
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Ingår i: The British journal of ophthalmology. - : BMJ. - 1468-2079 .- 0007-1161. ; 94, s. 97-100
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Super-resolution refers to computational enhancement of detail in sets of similar images, particularly under-sampled images. Under-sampling is a key feature of visual disorders associated with neuro-retinal matrix damage. It is conceivable that a biological equivalent of super-resolution might be recruited in these settings. The need for sets of similar images might be satisfied by augmenting retinal image movements. METHODS: Monocular letter acuity thresholds were measured by computer graphics in normal subjects, with and without controlled test target movements. Various degrees of neuro-retinal matrix defects were simulated by superposing stationary masks on the test targets. RESULTS: Static acuity thresholds increased monotonically with increased mask densities. The addition of target movement partially counteracted the threshold increment. The effect was barely measurable at small mask densities and increased monotonically to a gain of approximately 2 lines on a decimal acuity scale with masks simulating loss of 90% of neural matrix elements. Similar results were obtained from a patient with an acquired neuro-retinal matrix defect, attesting to the validity of the mask experiments. CONCLUSION: Super-normal retinal image movements have subtle effects on visual resolution in normal eyes whereas eyes with neuro-retinal matrix defects may improve markedly. This finding may have implications for the development of aids for the visually handicapped.
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| 11. |
- Scott, CJ, et al.
(författare)
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Diagnosis and Grading of Papilledema in Patients with Raised Intracranial Pressure Using Optical Coherence Tomography vs Clinical Expert Assessment using a Clinical Staging Scale
- 2010
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Ingår i: Archives of ophthalmology. - : American Medical Association (AMA). - 1538-3601 .- 0003-9950. ; 128:6, s. 705-11
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To compare and contrast 2 methods of quantitating papilledema, namely, optical coherence tomography (OCT) and Modified Frisén Scale (MFS). METHODS: Digital optic disc photographs and OCT fast retinal nerve fiber layer (RNFL) thickness, fast RNFL map, total retinal thickness, and fast disc images were obtained in 36 patients with papilledema. Digital optic disc photographs were randomized and graded by 4 masked expert reviewers using the MFS. We performed Spearman rank correlations of OCT RNFL thickness, OCT total retinal thickness, and MFS grade from photographs. RESULTS: OCT RNFL thickness and MFS grade from photographs correlated well (R = 0.85). OCT total retinal thickness and MFS grade from photographs had a similar correlation of 0.87. Comparing OCT RNFL thickness with OCT total retinal thickness, a slope of 1.64 suggests a greater degree of papilledema thickness change when using the latter. CONCLUSIONS: For lower-grade abnormalities, OCT compares favorably with clinical staging of optic nerve photographs. With higher grades, OCT RNFL thickness processing algorithms often fail, with OCT total retinal thickness performing more favorably.
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| 12. |
- Winther, Christina, et al.
(författare)
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A compact rarebit test for macular diseases.
- 2010
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Ingår i: The British journal of ophthalmology. - : BMJ. - 1468-2079 .- 0007-1161. ; 94, s. 324-27
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rarebit testing implies probing for gaps in the neuro-retinal receptive field matrix, using bright micro dots on a dark background. Previous reports have found rarebit testing useful for the detection of macular lesions. In its original implementation the test requires darkroom facilities and a long test distance (2 m). METHODS: A self-contained rarebit test device was realized using a modified miniature data projector driven by a laptop computer. Its performance was assessed in normal subjects and in patients with age-related macular degeneration. RESULTS: Normal subjects (N = 49) produced test results closely similar to those reported for the original rarebit fovea test. The patient group (N = 12) performed significantly worse. Reproducibility was good. Mean test time was 142 s. CONCLUSION: The new test allows portable rarebit testing for neuro-macular damage, without the need for a darkroom. It may prove useful for screening for early age-related macular degeneration.
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| 13. |
- Winther, Christina, et al.
(författare)
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New rarebit vision test captures macular deficits hidden to acuity tests
- 2015
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Ingår i: Acta Ophthalmologica. - : Wiley. - 1755-375X. ; 93:5, s. 481-485
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Tidskriftsartikel (refereegranskat)abstract
- PurposeEvaluation of a new personal-computer-based vision test aimed for rapid and accurate assessment of macular conditions such as age-related macular degeneration (AMD). MethodsThe new test depends on segmented digits defined by rarebits, that is, receptive field-size bright dots briefly presented against a dark background. Digit size was fixed at 40x50min of arc. Digit positions were varied at random within a 4.6x3.5-degree test field. There were no fixation demands. The number of rarebits per digit segment could be varied between 3 (the minimum needed for veridical perception) and 128, in 11 preset steps. The test task was to find the smallest rarebit number required to recognize the test digits. Thirty-seven patients with various stages of AMD and 25 control subjects participated in the evaluation, which also included a standard acuity test. ResultsAnalysis of receiver operating characteristics indicated significantly better discrimination by the rarebit test. Rarebit numbers >16 appeared to reliably indicate the presence of oedema. ConclusionThe rarebit test appeared well suited for fine grading of vision in AMD. The simple set-up and the lack of fixation demands made for practicable examinations of short durations. The test is available for free on the Internet.
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| 14. |
- Winther, Christina, et al.
(författare)
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Self-Testing of Vision in Age-Related Macula Degeneration: A Longitudinal Pilot Study Using a Smartphone-Based Rarebit Test
- 2015
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Ingår i: Journal of Ophthalmology. - : Hindawi Limited. - 2090-004X .- 2090-0058. ; :Article ID 285463
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. There is a need for efficient self-tests of vision in patients with neovascular age-related macula degeneration. A new tablet/smartphone application aiming to meet this need is described and its performance is assessed in a longitudinal pilot study. Materials and Methods. The new MultiBit Test (MBT) employs segmented digits defined by rarebits, that is, receptive field-size bright dots briefly presented against a dark background. The number of rarebits per digit segment was varied in a cyclic fashion, in preset steps. There were no fixation demands. Twenty-eight patients with neovascular AMD of varying severity were monitored for an average of 30 weeks. Test scores were evaluated on an individual basis, by contrasting observed trends with the clinical status recorded at independently scheduled clinical examinations. Results. Serial plots of MBT results revealed gradual improvement after successful antineovascular treatment. Recurrences were signalled by gradual deteriorations of results. Test results remained stable during clinically stable time intervals. MBT results agreed well with clinical assessments whereas an acuity test performed at chance level. The MBT was well accepted by all subjects. Conclusions. The MBT appears to have a good potential for effective self-testing of vision in AMD and merits large-scale studies. Exploration of MBT performance with other forms of macula conditions may be worthwhile.
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