Between-Subject Variability in Asymmetry Analysis of Macular Thickness

Alluwimi, Muhammed S.; Swanson, William H.; Malinovsky, Victor E.

doi:10.1097/opx.0000000000000249

Cited by 16 publications

(15 citation statements)

References 43 publications

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“…Um et al 19 proposed using five zones that cover most of the posterior pole grid and mimic the glaucoma hemifield test. In a previous study from our laboratory, 20 we demonstrated that there was high normal between-subject variability of the asymmetry analysis in the peripheral regions of the grid, and this variation could be reduced using the asymmetry analysis. However, our study was limited by using retinal thickness measurements without segmenting out the ganglion cell layer and retinal nerve fiber layer, the most affected layers in patients with glaucoma.…”

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confidence: 69%

“…Three zones were developed within the posterior pole grid based on regions with low between-subject variability that we found in our previous study, 20 in which normative data were collected from a homogenous group of young healthy control participants (Fig. 1 ).…”

Section: Methodsmentioning

confidence: 99%

“…In this study, our goal was to apply the asymmetry analysis in a subset of the posterior pole grid boxes based on the trajectory of the retinal nerve fiber layer, the clinical knowledge of the patterns of glaucomatous damage within the macula, and the regions that we found in our previous study 20 to have low variability of the asymmetry analysis. We aimed to improve the interpretation of the asymmetry analysis to provide better assessment of macular damage in patients with glaucoma.…”

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confidence: 99%

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Identifying Glaucomatous Damage to the Macula

Alluwimi¹,

Swanson²,

King³

2018

Optom Vis Sci

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SIGNIFICANCEMeasurements of the macula have been increasingly used to diagnose and manage patients with glaucoma. Asymmetry analysis was clinically introduced to assess damage to the macular ganglion cells in patients with glaucoma, but its effectiveness is limited by high normal between-subject variability.PURPOSEWe aimed to reduce the high normal between-subject variability and improve the potential of asymmetry analysis to identify glaucomatous damage to the macula.METHODSTwenty patients with glaucoma (aged 57 to 85 years) and 30 age-similar control subjects (aged 53 to 89 years) were recruited from a longitudinal glaucoma study. Participants were imaged with the Spectralis OCT using the posterior pole protocol; measurements of the averaged retinal thickness and ganglion cell layer (GCL) thickness were obtained. We established three zones per hemifield within the central ±9°, based on the lowest between-subject variability that we previously found and the course of retinal nerve fiber layer projections. The criteria for flagging abnormality were at least two contiguous zones when P < 5% or one zone when P < 1% with two-tailed tests.RESULTSBetween-subject variability of the asymmetry analysis for both retinal and GCL thicknesses remained lower than that of the average thickness across each zone in control subjects (F > 2.52, P < .01). Asymmetry analysis of retinal and GCL thicknesses flagged 16 and 18 of 20 patients, respectively.CONCLUSIONSBetween-subject variability was reduced in control subjects using the three zones; our criteria identified glaucomatous damage to the macula in most of the patients. We used high-density B-scans to confirm the patterns of the glaucomatous damage we found in this study.

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confidence: 69%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Identifying Glaucomatous Damage to the Macula

Alluwimi¹,

Swanson²,

King³

2018

Optom Vis Sci

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“…However, for the purpose of detailed investigation of eyes with glaucoma, a more layered approach may have some benefits. For instance, Curcio and Allen 21 reported that the ganglion cell topography varies along the different retinal meridians; however, other work 22 noted that the ganglion cell topography only contributes in a small proportion to the total macular shape. In glaucoma, outer retinal changes such as photoreceptor swelling may also occur additionally 23 contributing to differences in whole retinal thickness.…”

Section: Discussionmentioning

confidence: 99%

Individual Differences in Foveal Shape: Feasibility of Individual Maps Between Structure and Function Within the Macular Region

Sepulveda

Turpin

McKendrick

2016

Invest. Ophthalmol. Vis. Sci.

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Citation: Sepulveda JA, Turpin A, McKendrick AM. Individual differences in foveal shape: feasibility of individual maps between structure and function within the macular region. Invest Ophthalmol Vis Sci. 2016;57:4772-4778. DOI:10.1167/ iovs.16-19288 PURPOSE. Recently in glaucoma, different mapping schemes to combine structural and functional information within the macula have been proposed. This paper aims to investigate whether the changes in foveal shape parameters are important in the mapping between structure and function within the macular region.METHODS. Twenty younger adults (aged 24-to 33-years old) and 10 older adults (aged 62-to 76-years old) participated. On each subject, four foveally-centered radial spectral-domain optical coherence tomography (SD-OCT) scans with 458 of separation between each scan were acquired. After scan acquisition, foveal shape was extracted by fitting a previously proposed model that has been used to customize structure-function mapping in the macular region. Three parameters were obtained from the scans and then compared: the central thickness, the maximum thickness, and the radius.RESULTS. There were significant differences in the foveal shape parameters between subjects. There was no main effect of the scan axis for the central thickness; however, there was an interaction between the scan axis and maximum thickness and between the scan axis and radius. With respect to the effect of age, we did not find a main effect for the central thickness, the maximum thickness or the radius, although this parameter approached statistical significance. CONCLUSIONS.In our study, we demonstrated that the foveal shape is different for different subjects, but predictable superiorly and inferiorly within an individual. Our study highlights features important for the development of individually customized structure-function maps for the investigation of glaucomatous damage in the macular region.

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“…Furthermore, there is variation of the RGC distribution in the retina among the human population and the macula is strong candidate for the site of least variability 50 . In addition,…”

Section: Introductionmentioning

confidence: 99%

Defining the structure - function horizontal meridian of the human macula

Lemor¹

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2 AbstractPurpose: To investigate the congruency of the retinal ganglion cell structure -function relationship in the macular region of human subjects who manifest horizontal split fixation due to glaucoma. Subjects with glaucoma who manifest asymmetric loss of retinal ganglion cells across the horizontal meridian macula were examined using structural measures provided by spectral domain optical coherence tomography (SD-OCT) and functional measures using automated visual field perimetry (HVF). Using this data, the horizontal meridian of the human macula was defined using structure -function linking analysis of retinal ganglion cell integrity.Methods: 26 stable glaucoma subjects who manifest split fixation on HVF 24-2 S/S testing were identified and performed Heidelberg Spectralis® SD-OCT posterior pole asymmetry analyses. The posterior pole asymmetry analysis image was oriented in a systematic manner so that the macular thickness grid was centered on the fovea and its horizontal meridian intersected the optic nerve head at five pre-selected equidistant locations along the central vertical axis. The posterior pole asymmetry analysis for each optic nerve head intercept generated average superior and inferior retinal hemifield and temporal quadrant thicknesses and the superior to inferior thickness ratio calculated. Tukey post-hoc pairwise comparisons of the hemifield and quadrant thickness ratios demonstrate a significant difference between the superior and inferior poles (p<.01). The SD-OCT thickness ratios for both the hemifield and temporal quadrants increase as the horizontal meridian migrates towards the inferior pole of the optic nerve head.Conclusions: We demonstrate that in order to maximize the hemifield ratio and the congruency of the macular structure -function relationship in subjects with glaucoma, the horizontal meridian of the posterior pole asymmetry grid should intersect the optic nerve head near the inferior pole. This is in contradistinction to the conventional practice of placing the horizontal median through the geometric center of the optic nerve head.3

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Between-Subject Variability in Asymmetry Analysis of Macular Thickness

Cited by 16 publications

References 43 publications

Identifying Glaucomatous Damage to the Macula

Identifying Glaucomatous Damage to the Macula

Individual Differences in Foveal Shape: Feasibility of Individual Maps Between Structure and Function Within the Macular Region

Defining the structure - function horizontal meridian of the human macula

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