Structure-Function Modeling of Optical Coherence Tomography and Standard Automated Perimetry in the Retina of Patients with Autosomal Dominant Retinitis Pigmentosa.

Travis B Smith,Richard G Weleber,Peter N Steinkamp,Maria Parker,Ning Smith,David J Wilson,Alfred S Lewin

doi:10.1371/journal.pone.0148022

Travis B Smith, Richard G Weleber + Show 5 more

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https://doi.org/10.1371/journal.pone.0148022

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Abstract

PurposeTo assess relationships between structural and functional biomarkers, including new topographic measures of visual field sensitivity, in patients with autosomal dominant retinitis pigmentosa.MethodsSpectral domain optical coherence tomography line scans and hill of vision (HOV) sensitivity surfaces from full-field standard automated perimetry were semi-automatically aligned for 60 eyes of 35 patients. Structural biomarkers were extracted from outer retina b-scans along horizontal and vertical midlines. Functional biomarkers were extracted from local sensitivity profiles along the b-scans and from the full visual field. These included topographic measures of functional transition such as the contour of most rapid sensitivity decline around the HOV, herein called HOV slope for convenience. Biomarker relationships were assessed pairwise by coefficients of determination (R2) from mixed-effects analysis with automatic model selection.ResultsStructure-function relationships were accurately modeled (conditional R2>0.8 in most cases). The best-fit relationship models and correlation patterns for horizontally oriented biomarkers were different than vertically oriented ones. The structural biomarker with the largest number of significant functional correlates was the ellipsoid zone (EZ) width, followed by the total photoreceptor layer thickness. The strongest correlation observed was between EZ width and HOV slope distance (marginal R2 = 0.85, p<10−10). The mean sensitivity defect at the EZ edge was 7.6 dB. Among all functional biomarkers, the HOV slope mean value, HOV slope mean distance, and maximum sensitivity along the b-scan had the largest number of significant structural correlates.ConclusionsTopographic slope metrics show promise as functional biomarkers relevant to the transition zone. EZ width is strongly associated with the location of most rapid HOV decline.

Highlights

Retinitis pigmentosa (RP) is a heterogeneous group of genetic disorders that primarily affects photoreceptors and the retinal pigment epithelium, leading to progressive outer retinal thinning and loss of visual function [1,2,3,4,5]
Structure-Function Modeling of optical coherence tomography (OCT) and standard automated perimetry (SAP) in RP Patients
ellipsoid zone (EZ) width is strongly associated with the location of most rapid hill of vision (HOV) decline

Summary

Introduction

Retinitis pigmentosa (RP) is a heterogeneous group of genetic disorders that primarily affects photoreceptors and the retinal pigment epithelium, leading to progressive outer retinal thinning and loss of visual function [1,2,3,4,5]. Previous studies of RP patients have described coincident relationships between visual function and several structural biomarkers. These include the thicknesses of the outer nuclear layer [6,7], outer segment [7,8], and outer retina [8,9], and the intactness of the external limiting membrane [9] and the width of the ellipsoid zone (EZ, or the inner segment-outer segment junction) [7,9,10]. A decline in the integrity or extent of the EZ has been associated with RP progression and visual field loss [7,9,12,13,14,15] In these studies, retinal structures were measured with optical coherence tomography (OCT) or fundus autofluorescence imaging and visual function was assessed by multifocal electroretinography or static perimetry of the central macula

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