Recent developments in perimetry: test stimuli and procedures

McKendrick, Allison M

doi:10.1111/j.1444-0938.2005.tb06671.x

Cited by 47 publications

(44 citation statements)

References 67 publications

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“…The RFT is included in the Rarebit perimeter, extensively described elsewhere. 4,6 The technique has been used in several studies regarding glaucoma and neuro-ophthalmologic disorders and software is available free of charge from Lars.Frisen@neuro.gu.se.…”

Section: Methodsmentioning

confidence: 99%

Perception of very small visual stimuli in the fovea: normative data for the Rarebit Foveal Test

Nilsson¹,

Wanger²,

Martin³

2006

Clinical and Experimental Optometry

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Recently, the Rarebit Fovea Test (RFT) was developed with the explicit aim of improving detection of low-degree neural damage. 4,5 It relies on very small bright dots of light, briefly shown against a dark background and subtending a visual angle of approximately 0.5 minutes of arc. Thus, the retinal image of the dot is small compared to receptive field size. 4 The results from the RFT are presented as mean hit rates, that is, the proportion of perceived dots expressed as a percentage of all presented dots. In a previous study, the median of the mean hit rates, obtained from normal subjects, was 100 per cent (range 97 to 100) in the age group below 65 years and 87.5 per cent (range 34 to 98) in subjects older than 65 years.5 These results indicate a 'ceiling effect', that is, the Background: Conventional visual tests are not sensitive enough to detect low degree neural damage, as 6/6 (1.0) visual acuity can be upheld with less than two-thirds of the normal number of optic nerve axons. The aim of the current study was to evaluate the physiologic properties of a new computerised test, the Rarebit Fovea Test (RFT), using very small stimuli, by quantifying the effect of age and binocular summation in relation to stimulus luminance. Methods: The RFT relies on the perception of very small (less than 0.5 minutes of arc) bright stimuli. Two different experiments were performed. 1. Thirty-five subjects (age 19 to 63 years) were tested with five different stimulus luminances, 158, 64, 53, 41 and 33 cd/m 2 . 2. Nineteen subjects (age 19 to 63 years) were tested using binocular stimulation to define the binocular summation. Results: Significantly reduced median hit rates were observed at luminances of 53 cd/m 2 or below. Age and mean hit rate correlated negatively at all luminance levels below 158 cd/m 2 . The mean hit rate from binocular stimulation, compared to the highest value from monocular stimulation in the same subject, was increased by a factor of 1.54 ± 0.45 (SD). No age effect was found regarding binocular summation. Conclusions:The results in the current study indicate that RFT can identify some of the well-known features of the visual system, that is, the effects of age and binocular summation, provided that the stimulus luminance is adequately selected.

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Section: Methodsmentioning

confidence: 99%

Perception of very small visual stimuli in the fovea: normative data for the Rarebit Foveal Test

Nilsson¹,

Wanger²,

Martin³

2006

Clinical and Experimental Optometry

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“…Rota-Bartelink, 1999 for review), methods that include a recognition task like MacKeben's Macular Mapping Test (Hahn et al, 2009), microperimetry, and the scanning laser ophthalmoscope (SLO; Mainster, Timberlake, Webb, & Hughes, 1982;Rohrschneider, Springer, Bültmann, & Völcker, 2005), as well as objective techniques like the multifocal electroretinogram (Sutter & Tran, 1992). Some of the techniques and implemented test algorithms are briefly reviewed by McKendrick (2005). Further information can be found at the Imaging and Perimetry Society's site (http://www.…”

Section: Perimetrymentioning

confidence: 98%

Peripheral vision and pattern recognition: A review

2011

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We summarize the various strands of research on peripheral vision and relate them to theories of form perception. After a historical overview, we describe quantifications of the cortical magnification hypothesis, including an extension of Schwartz's cortical mapping function. The merits of this concept are considered across a wide range of psychophysical tasks, followed by a discussion of its limitations and the need for non-spatial scaling. We also review the eccentricity dependence of other low-level functions including reaction time, temporal resolution, and spatial summation, as well as perimetric methods. A central topic is then the recognition of characters in peripheral vision, both at low and high levels of contrast, and the impact of surrounding contours known as crowding. We demonstrate how Bouma's law, specifying the critical distance for the onset of crowding, can be stated in terms of the retinocortical mapping. The recognition of more complex stimuli, like textures, faces, and scenes, reveals a substantial impact of mid-level vision and cognitive factors. We further consider eccentricity-dependent limitations of learning, both at the level of perceptual learning and pattern category learning. Generic limitations of extrafoveal vision are observed for the latter in categorization tasks involving multiple stimulus classes. Finally, models of peripheral form vision are discussed. We report that peripheral vision is limited with regard to pattern categorization by a distinctly lower representational complexity and processing speed. Taken together, the limitations of cognitive processing in peripheral vision appear to be as significant as those imposed on low-level functions and by way of crowding.

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“…Computerized Rarebit perimetry (RB), extensively described elsewhere (Frise´n 2002;McKendrick 2005), was used for VF evaluation. The technique has previously been shown to be suitable for examining children from the age of 6-7 years Martin & Lundvall Nilsson 2007) .…”

Section: Visual Field Testingmentioning

confidence: 99%

Visual fields in children with attention‐deficit / hyperactivity disorder before and after treatment with stimulants

Martin

Aring

Landgren

et al. 2008

Acta Ophthalmologica

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ABSTRACT.Purpose: This study aimed to evaluate visual function in children with attention-deficit ⁄ hyperactivity disorder (ADHD), to correlate these data with the morphology of the optic nerve, and to find out if and how psychostimulant medication affects visual functions. Methods: The visual acuity (VA) and visual fields (VFs) of 18 children with ADHD (two girls and 16 boys), aged 6-17 years, were examined before and after treatment with psychostimulants. A control group, consisting of 24 children (nine girls and 15 boys), aged 7-18 years, were examined twice to evaluate the repeatability of the tests and the learning effect. Fundus photographs were analysed by digital planimetry. Results: Visual acuity increased significantly (p = 0.0039) in the ADHD group after treatment. The difference between the two VF examinations was significantly larger in the ADHD group compared with the control group (p = 0.036). Significantly more ADHD subjects had subnormal VF results without stimulants, compared with controls (p = 0.0043), but with stimulants the difference was no longer significant. Conclusions: Children with ADHD showed better VA and VF results with than without psychostimulant medication.

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Recent developments in perimetry: test stimuli and procedures

Cited by 47 publications

References 67 publications

Perception of very small visual stimuli in the fovea: normative data for the Rarebit Foveal Test

Perception of very small visual stimuli in the fovea: normative data for the Rarebit Foveal Test

Peripheral vision and pattern recognition: A review

Visual fields in children with attention‐deficit / hyperactivity disorder before and after treatment with stimulants

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