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

Abstract

When compared to the current Goldmann III paradigm, the use of alternate sized targets within the 30-2 testing protocol revealed a greater loss in patients with optic nerve disease for both event analysis and global indices (MD and PSD). We therefore provide evidence in a clinical setting that target size is important in visual field testing.

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

“…Therefore, selection of a stimulus size within the spatial summation area but not smaller than truly necessary may maximize the signal-to-noise ratio. Previous studies have suggested the spatial summation area within the central 108 to be closest to but larger than GII, 24,25,31 and therefore, consistent with our data suggesting GII is more effective than both GI and GIII for the central retina. On the other hand, spatial summation area increases with the disease process, 28 and in such case, a stimulus larger than the normal spatial summation area may be more appropriate.…”

“…21,[44][45][46] The age difference between individual subjects and the cohorts may therefore increase the variability within the dataset and confound the comparison of structure-function relationship between the normal and glaucomatous cohort. Hence, to minimize the variability imposed by intra-and intercohort age differences, the GCL thickness and DLS of all normal and glaucomatous subjects were age-corrected to the average age of the glaucomatous cohort using previously established regression analysis models as conducted in previous studies, 11,21,[24][25][26]31,32,45,47 including the commonly used SITAstandard algorithm of the HFA. 48 Specifically, for the GCL thickness, measurements from each normal and glaucomatous subjects were clustered into eight statistically separable classes and adjusted to match the average age of the glaucomatous cohort using a previously published conversion for all but the foveal area.…”

“…21 The difference imposed by age between these cohorts is within the test-retest variability range of the instruments, [44][45][46][47][48][49][50][51][52][53][54][55][56] and even before correction, there were notable overlaps between the prediction interval for the regression curves of the two cohorts (data not shown). Regardless, DLS and GCc for the normal and glaucomatous cohort were adjusted to a common age equivalent using a wellestablished age-correction method, frequently used in prior studies by different investigators 11,21,[24][25][26]31,32,45,47 and regularly utilized by clinical test algorithms for the Humphrey Field Analyzer; SITA. 48 A subanalysis was conducted to further confirm the validity of the age-correction technique, and good fidelity was demonstrated between the glaucomatous subgroup, and the normal age-corrected and age-matched cohorts ( Supplementary Fig.…”

Pattern Recognition Analysis of Age-Related Retinal Ganglion Cell Signatures in the Human Eye

“…10,14,22 While there are studies that show the average GC soma diameter to decrease with glaucomatous neuropathy, which may lead to reduction in neural density, 15,68,69 it does not alter significantly with age. 9 Furthermore, recent studies have highlighted the limitation of conventional visual field strategy utilizing stimulus size not scaled for spatial summation area, 70–72 a potential confounding factor for any such structure–function comparison. Thus, a structure–function study comparing GC density to appropriately scaled visual stimulus and further analysis of GC density per volume may be required to clarify the relationship.…”

“…For instance, either of the temporal regression models may be applied for conversion of GCL thickness data to a given age equivalent in a similar fashion to visual field regression data 66 used in previous studies. 70,75–77 The spatial theme class schema may be implemented in structure–function concordance study by allowing multiple measurement areas to be analyzed together and facilitate spatial translation of GCL data to visual field data points. A preliminary result on similar pattern recognition study on visual field revealed a similar spatial pattern to be present when stimulus size was adjusted for spatial summation area (Kalloniatis M, et al IOVS 2016;57:ARVO E-Abstract 4745), and further comparison of spatial and temporal characteristics of the two modalities may shed further light onto structure–function concordance.…”