Spatiotemporal Summation of Perimetric Stimuli in Early Glaucoma

Mulholland, Pádraig J.; Redmond, Tony; Garway-Heath, David F.; Zlatkova, Margarita; Anderson, R. H.

doi:10.1167/iovs.15-16921

Cited by 34 publications

(89 citation statements)

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“…The results of this study support the proposition of Anderson that testing within complete spatial summation provides a mechanism to identify a larger threshold elevation in ocular disease. Both spatial and temporal aspects are important in threshold determination applicable to visual field testing . The following discussion focuses on spatial considerations.…”

Section: Discussionmentioning

confidence: 99%

“…Other methods have also scaled for differences in foveal to peripheral sensitivity, or vary target size while maintaining target contrast constant (STP) . Scaling methods include using the cortical magnification factor; using the slope of the coefficient of summation (k1) for a Goldmann III target to calculate differential light sensitivity and determine the relationship with ganglion cell density; aligning target size with the critical area (Ac), derived from spatial summation studies of Ricco's law at different retinal eccentricities . Latham et al .…”

Section: Discussionmentioning

confidence: 99%

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Equating spatial summation in visual field testing reveals greater loss in optic nerve disease

Kalloniatis

Khuu

2016

Ophthalmic Physiologic Optic

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Equating spatial summation in visual field testing reveals greater loss in optic nerve disease

Kalloniatis

Khuu

2016

Ophthalmic Physiologic Optic

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“…15,[28][29][30][31][32] Within the central 308 of the field of vision, at which threshold visual field tests are most commonly conducted, the GIII target often exceeds spatial summation area, particularly for the central test locations. 24,25 Given the importance of test size in relation to the Ac to the fidelity of visual sensitivity, 15,[28][29][30]32 we hypothesize that the GC structure-function relationship will improve and approach 1:1 positive correlation by altering the test size within complete spatial summation. Similarly, as the summation characteristic is known to change with the disease process, 28 comparisons of the structure-function relationship between normal and glaucomatous cohorts need to be conducted.…”

mentioning

confidence: 99%

Consistency of Structure-Function Correlation Between Spatially Scaled Visual Field Stimuli and In Vivo OCT Ganglion Cell Counts

Yoshioka

Zangerl

Phu

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. To investigate the effect of stimulus size and disease status on the structure-function relationship within the central retina, we correlated the differential light sensitivity (DLS) with Goldmann stimulus size I to V (GI-V) and optical coherence tomography (OCT) derived in vivo ganglion cell count per stimulus area (GCc) within the macular area in normal subjects and patients with early glaucoma.METHODS. Humphrey Field Analyzer 10-2 visual field data with GI through V and Spectralis OCT macular ganglion cell layer (GCL) thickness measurements were collected from normal and early glaucoma cohorts including 25 subjects each. GCc was calculated from GCL thickness data and correlated with DLSs for different stimulus sizes.RESULTS. Correlation coefficients attained with smaller stimulus size were higher compared to larger stimulus sizes in both normal (GI-GII: R 2 ¼ 0.41-0.43, GIII-GV: R 2 ¼ 0.16-0.41) and diseased cohorts (GI-GII: R 2 ¼ 0.33-0.41, GIII-GV: R 2 ¼ 0.19-0.36). Quadratic regression curves for combined GI to V data demonstrated high correlation (R 2 = 0.82-0.90) and differed less than 1 dB of visual sensitivity within the GCc range between cohorts. The established structure-function relationship was compatible with a histologically derived model correlation spanning the range predicted by stimulus sizes GI to GIII.CONCLUSIONS. Stimulus sizes within critical spatial summation area (GI-II) improved structurefunction correlations in the central visual field. The structure-function relationship was identical in both normal and diseased cohort when GI to GV data were combined. Congruency of GI and GII structure-function correlation with those previously derived with GIII from more peripheral locations further suggests that the structure-function relationship is governed by the number of ganglion cell per stimulus area.

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“…From this equation, Ricco's law of spatial summation ( L.A n1 = k ) and Bloch's law of temporal summation ( L.t n2 = k ) can be derived . When n is equal to one, the test stimulus is operating within the critical area (Ac) or critical duration (Tc) of complete summation and there is a linear relationship between luminance and stimulus duration; outside of Tc or Ac, this relationship is non‐linear …”

Section: Test Parameters Used In Standard Automated Perimetrymentioning

confidence: 99%

“…Conversely, OCT imaging has been suggested to show more loss at the beginning but plateaus in advanced stages of disease due to the floor effect of its measurement technique (see Table 3 and Figure in Medeiros and colleagues). More recent studies have shown that equating for spatiotemporal summation characteristics can allow detection of functional losses in earlier stages of glaucoma . Simple modifications of test stimuli at different visual field test locations can specifically maximise defect detection, while maintaining the widest dynamic range of testing .…”

Section: The Problem Of Structure‐function Discordancementioning

confidence: 99%

The value of visual field testing in the era of advanced imaging: clinical and psychophysical perspectives

Phu

Khuu

Yapp

et al. 2017

Clinical and Experimental Optometry

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White‐on‐white standard automated perimetry (SAP) is widely used in clinical and research settings for assessment of contrast sensitivity using incremental light stimuli across the visual field. It is one of the main functional measures of the effect of disease upon the visual system. SAP has evolved over the last 40 years to become an indispensable tool for comprehensive assessment of visual function. In modern clinical practice, a range of objective measurements of ocular structure, such as optical coherence tomography, have also become invaluable additions to the arsenal of the ophthalmic examination. Although structure‐function correlation is a highly desirable determinant of an unambiguous clinical picture for a patient, in practice, clinicians are often faced with discordance of structural and functional results, which presents them with a challenge. The construction principles behind the development of SAP are used to discuss the interpretation of visual fields, as well as the problem of structure‐function discordance. Through illustrative clinical examples, we provide useful insights to assist clinicians in combining a range of clinical results obtained from SAP and from advanced imaging techniques into a coherent picture that can help direct clinical management.

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Spatiotemporal Summation of Perimetric Stimuli in Early Glaucoma

Cited by 34 publications

References 50 publications

Equating spatial summation in visual field testing reveals greater loss in optic nerve disease

Equating spatial summation in visual field testing reveals greater loss in optic nerve disease

Consistency of Structure-Function Correlation Between Spatially Scaled Visual Field Stimuli and In Vivo OCT Ganglion Cell Counts

The value of visual field testing in the era of advanced imaging: clinical and psychophysical perspectives

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