Frequency Doubling in Visual Responses*†

Kelly, D. H.

doi:10.1364/josa.56.001628

Cited by 294 publications

(153 citation statements)

References 9 publications

Supporting

Mentioning

138

Contrasting

Unclassified

Order By: Relevance

“…6,7 It is based on the frequency-doubling effect first described by Kelly,13 in which a sinusoidal grating of lowspatial frequency undergoing high temporal frequency produces a perceived spatial frequency that is doubled. Numerous studies have shown that FDT is able to detect VF loss before SAP 14 and that it can predict the progression and morphology of future SAP VF defects.…”

Section: Introductionmentioning

confidence: 99%

Non-conventional perimetric methods in the detection of early glaucomatous functional damage

Salvetat

Zeppieri

Tosoni

et al. 2009

Eye

View full text Add to dashboard Cite

Purpose To compare the ability of frequencydoubling technology (FDT), rarebit perimetry (RBP), and pulsar perimetry (PP) in detecting early glaucomatous functional damage. Methods This prospective observational cross-sectional case study included 52 patients with early primary open-angle glaucoma (mean deviation À2.3 ± 1.1 dB; pattern standard deviation 3.0±1.2 dB) and 53 healthy controls. Visual field (VF) testing included standard automated perimetry (SAP) Humphrey Field Analyzer 30-2, FDT N-30, RBP (version 4.0), and PP T30W. One eye per patient was considered. Sensitivity at fixed specificities and area under the receiver operating characteristic curve (AROC) for discriminating between healthy and glaucomatous eyes were calculated and compared. Results The parameters associated with the largest AROC, which were not statistically different (Hanley-McNeil method, P 0.42-0.71) were as follows: number of locations in the pattern deviation probability (PDP) plot with Po5% for FDT (0.93); mean hit rate for RBP (0.95); and mean defect for PP (0.94). PP test duration was significantly shorter than FDT and RBP (Po0.002). Conclusions FDT, PP, and RBP are useful non-conventional VF methods in detecting early glaucomatous VF defects with similar AROCs. The methods were rapid and easy, and PP took less than half the time than SAP. These non-conventional testing may prove to be useful in providing additional information in the diagnosis of glaucoma suspect with normal SAP results, in the therapeutic decision-making process of early glaucomatous patients, and in subjects unable to perform VF testing with SAP.

show abstract

Section: Introductionmentioning

confidence: 99%

Non-conventional perimetric methods in the detection of early glaucomatous functional damage

Salvetat

Zeppieri

Tosoni

et al. 2009

Eye

View full text Add to dashboard Cite

show abstract

“…It utilises the frequencydoubling illusion, in which a sine wave grating of low spatial frequency undergoing counterphase flicker at high temporal frequency appears to the observer to have double the number of bars than are actually present. 1 This psychophysical 'illusion' is thought to be mediated by My ganglion cells that are a subset of the magnocellular system. 2 The FDT has shown high sensitivity and specificity in identifying patients with glaucomatous visual field loss and has been advocated as a suitable screening test for glaucoma 3,4 (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Does frequency doubling technology perimetry reliably detect neurological visual field defects?

Fong

Byles

Constable

2003

Eye

View full text Add to dashboard Cite

Aim To determine the ability of frequency doubling technology (FDT) perimetry to detect visual field defects of neurological origin. Methods A total of 15 eyes of nine patients who all had complete hemianopias or quadrantanopias underwent the FDT 20-5 screening mode test and Humphrey 24-2 SITA Fast visual field test (HFA). The FDT results were scored according to the number of abnormal test locations (out of a maximum of 4) in each affected quadrant. FDT locations showing a defect of Po2% were considered abnormal. Results Of the 15 eyes, six showed complete superior quadrantanopic and nine complete hemianopic field defects on HFA. Of 96 FDT test locations in these quadrants or hemifields only 38 were abnormal on FDT testing (40%). For the quadrantanopic field defects, five out of 24 locations were abnormal (21%). For the hemianopic field defects, 33 out of 72 locations were abnormal (49%). In three eyes (two with quadrantanopias and one with complete hemianopia), FDT perimetry failed to demonstrate any corresponding abnormality. Conclusions The FDT screening test can fail to demonstrate complete hemianopic and quadrantanopic field defects. Users should be aware of this deficiency when using FDT to screen for field defects.

show abstract

“…2 Currently, standard automated perimetry (SAP) is the clinical test most often used for evaluating the visual field (VF) in these patients, however, many newer instruments are continuously being developed to improve the diagnostic yield and shorten the test duration, to help reduce the fatigue induced by the test and increase patient acceptability. [3][4][5][6][7] Frequency doubling technology (FDT) is based on a phenomenon called the 'frequency doubling illusion', which occurs when low spatial frequency (o1 cycle/degree) grating undergoes high temporal frequency (415 Hz) counterphase flicker. 3,4 This type of illusion is thought to be mediated by the magnocellular retinal ganglion cells, whose loss, probably because of reduced redundancy, may be detectable in early glaucoma.…”

Section: Introductionmentioning

confidence: 99%

Learning effect in visual field testing of healthy subjects using Humphrey Matrix frequency doubling technology perimetry

Pierre-Filho¹,

Gomes²,

Pierre³

et al. 2009

Eye

View full text Add to dashboard Cite

Purpose To evaluate the learning effect of frequency doubling technology (FDT) perimetry using the Humphrey Matrix perimeter in healthy subjects with no perimetric experience. Methods One eye of 28 healthy adults who had no history of visual field testing underwent three Matrix tests using 24-2 programme with full-threshold strategy. The results of the first session were compared with those of the second, and the third sessions. Learning effect was defined as an improvement at results for duration, perimetric indices, and the number of points with a Po5 and o1% in the total and pattern deviation maps. Anderson's criteria were applied to define abnormal examinations. Results The mean in the mean deviation global index was À7.40 ± 1.49 dB in the first session, À4.64±0.97 dB in the second session, and À3.29±0.93 dB in the third session. Pattern standard deviations were decreased as the tests were repeated (Po0.01). Test duration, fixation losses, false negative, and the number of points with a Po5 and o1% in the total and pattern deviation maps rate were also changed significantly (Po0.05). Among the criteria suggested by Anderson, the Glaucoma Hemifield Test performed better in all session tests. The false-positive rates ranged from 50% (95% confidence intervals [CI] 30.6-69.4%) to 64% (95% CI 44.1-81.4%) for the first session, 29% (95% CI 13.2-48.7%) to 54% (95% CI 33.9-72.5%) for the second session, and from 18% (95% CI 6.1-36.9%) to 32% (95% CI 15.9-52.4%) for the third session. ConclusionsThe results of this study show that the learning effect for Humphrey Matrix FDT perimetry must be considered in normal individuals with no perimetric experience.

show abstract

Frequency Doubling in Visual Responses*†

Cited by 294 publications

References 9 publications

Non-conventional perimetric methods in the detection of early glaucomatous functional damage

Non-conventional perimetric methods in the detection of early glaucomatous functional damage

Does frequency doubling technology perimetry reliably detect neurological visual field defects?

Learning effect in visual field testing of healthy subjects using Humphrey Matrix frequency doubling technology perimetry

Contact Info

Product

Resources

About