Diagnostic capability of a linear discriminant function applied to a novel Spectralis OCT glaucoma-detection protocol

Background Bruch membrane opening–minimum rim width (BMO–MRW) assessment offers a new diagnostic use in glaucoma patients of the Glaucoma Module Premium Edition (GMPE) available for the Spectralis optical coherence tomography (OCT) system. The objective of our research was to evaluate the diagnostic benefits of examining BMO–MRW and peripapillary retinal nerve fibre layer (pRNFL) readings acquired with Spectralis OCT to distinguish between healthy and mild glaucoma patients, comparing those readings with the standard pRNFL application. Moreover, we investigated whether using a particular combination of BMO–MRW and pRNFL parameters with a linear discriminant function (LDF) could further enhance glaucoma diagnosis. Methods One hundred thirty-six eyes from 136 individuals were incorporated into this observational, prospective cross-sectional study: 68 mild primary open-angle glaucoma (POAG) patients according to the Hodapp-Parrish-Anderson criteria (mean deviation between 0 and?-?6?dB) and 68 healthy control subjects selected by Propensity Score Matching. MRW and pRNFL thickness around the disc (diameters: 3.5?mm, 4.1?mm, and 4.7?mm) were obtained using the BMO–MRW protocol, and pRNFL thickness at 3.5?mm was obtained with the standard glaucoma application. The group data were contrasted. One sample was chosen at random to develop the LDF (teaching set: 34 healthy subjects and 34 POAG patients) using a combination of MRW and pRNFL parameters (acquired with the BMO–MRW protocol); the other sample provided a test of how the LDF performed on an independent group (validating set: 34 healthy subjects and 34 POAG patients). The receiver operating curves (ROCs) were plotted for every measurement and contrasted with the proposed LDF. The OCT parameters with the best area under the receiver operating characteristic curve (AUC) were determined. Results Global MRW and pRNFL thicknesses were significantly thinner in the POAG group (p?<? 0.001). The BMO–MRW parameters showed good diagnostic accuracy; the largest AUCs reached 0.875 for the LDF and 0.879 for global RNFL thickness using the standard glaucoma application. There were no statistical differences between the AUCs calculated. Conclusions BMO–MRW parameters show a strong capability to differentiate between mild glaucoma and control eyes. Our LDF based on the new BMO–MRW OCT protocol did not perform better than isolated parameters

Potential New Diagnostic Tool for Alzheimer&apos;s Disease Using a Linear Discriminant Function for Fourier Domain Optical Coherence Tomography

PURPOSE. We calculated and validated a linear discriminant function (LDF) for Fourier domain optical coherence tomography (OCT) to improve the diagnostic ability of retinal and retinal nerve fiber layer (RNFL) thickness parameters in the detection of Alzheimer&apos;s disease (AD). METHODS. We enrolled AD patients (n ¼ 151) and age-matched, healthy subjects (n ¼ 61). The Cirrus and Spectralis OCT systems were used to obtain retinal measurements and circumpapillary RNFL thickness for each participant. An LDF was calculated using all retinal and RNFL OCT measurements. Receiver operating characteristic (ROC) curves were plotted and compared among the LDF and the standard parameters provided by OCT devices. Sensitivity and specificity were used to evaluate diagnostic performance. A validating set was used in an independent population to test the performance of the LDF. RESULTS. The optimal function was calculated using the RNFL thickness provided by Spectralis OCT, using the 768 points registered during peripapillary scan acquisition (grouped to obtain 24 uniformly divided locations): 18.325 þ 0.056 3 (3158-3308) À 0.122 3 (3008-3158) À 0.041 3 (2858-3008) þ 0.091 3 (2558-2708) þ 0.041 3 (2258-2408) þ 0.183 3 (1958-2108) À 0.108 3 (1508-1658) À 0.092 3 (758-908) þ 0.051 3 (308-458). The largest area under the ROC curve was 0.967 for the LDF. At 95% fixed specificity, the LDF yielded the highest sensitivity values. CONCLUSIONS. Measurements of RNFL thickness obtained with the Spectralis OCT device differentiated between healthy and AD individuals. Based on the area under the ROC curve, the LDF was a better predictor than any single parameter

Alzheimer's Disease: a Review of its Visual System Neuropathology. Optical Coherence Tomography-a Potential Role As a Study Tool in Vivo

Alzheimer's disease (AD) is a prevalent, long-term progressive degenerative disorder with great social impact. It is currently thought that, in addition to neurodegeneration, vascular changes also play a role in the pathophysiology of the disease. Visual symptoms are frequent and are an early clinical manifestation; a number of psychophysiologic changes occur in visual function, including visual field defects, abnormal contrast sensitivity, abnormalities in color vision, depth perception deficits, and motion detection abnormalities. These visual changes were initially believed to be solely due to neurodegeneration in the posterior visual pathway. However, evidence from pathology studies in both animal models of AD and humans has demonstrated that neurodegeneration also takes place in the anterior visual pathway, with involvement of the retinal ganglion cells' (RGCs) dendrites, somata, and axons in the optic nerve. These studies additionally showed that patients with AD have changes in retinal and choroidal microvasculature. Pathology findings have been corroborated in in-vivo assessment of the retina and optic nerve head (ONH), as well as the retinal and choroidal vasculature. Optical coherence tomography (OCT) in particular has shown great utility in the assessment of these changes, and it may become a useful tool for early detection and monitoring disease progression in AD. The authors make a review of the current understanding of retinal and choroidal pathological changes in patients with AD, with particular focus on in-vivo evidence of retinal and choroidal neurodegenerative and microvascular changes using OCT technology.info:eu-repo/semantics/publishedVersio

Diagnostic ability of inner macular layers to discriminate early glaucomatous eyes using vertical and horizontal B-scan posterior pole protocols.

PURPOSE:To evaluate the diagnostic ability of macular ganglion cell (mGCL) and macular retinal nerve fiber (mRNFL) layers, to detect early glaucomatous eyes, using the new segmentation software of Spectralis optical coherence tomography (OCT) device (Heidelberg Engineering). METHODS:A total of 83 eyes from 83 subjects were included in this observational, prospective cross-sectional study: 43 healthy controls and 40 early primary open-angle glaucoma (POAG) patients. All participants were examined using the Horizontal and Vertical Posterior Pole protocols, and the peripapillary RNFL (pRNFL) protocol of Spectralis OCT device. The new automated retinal segmentation software was applied to horizontal and vertical macular B-scans to determine mGCL and mRNFL thicknesses in each one of the 9 sectors of the Early Treatment Diagnostic Retinopathy Study circle. Thickness of each layer was compared between groups, and the sectors with better area under the receiver operating characteristic curve (AUC) were identified. RESULTS:mGCL was significantly thinner in the POAG group, especially in outer and inner temporal sectors (p<0.001); and mRNFL was significantly thinner in the POAG group in the outer inferior and the outer superior sector (p<0.001). Diagnostic accuracy of inner macular layers was good, and in general mGCL was superior to mRNFL. pRNFL obtained the best diagnostic capability (AUC, 0.886). Horizontal and vertical Posterior Pole protocols performed similarly. CONCLUSIONS:Inner macular layers using either horizontal or vertical B-scans, especially temporal sectors of mGCL, have good diagnostic capability to differentiate early glaucomatous eyes from control eyes; however, pRNFL has the highest diagnostic sensitivity for glaucoma detection

New Normative Database of Inner Macular Layer Thickness Measured by Spectralis OCT Used as Reference Standard for Glaucoma Detection

Purpose: This study examines the capacity to detect glaucoma of inner macular layer thickness measured by spectral-domain optical coherence tomography (SD-OCT) using a new normative database as the reference standard. Methods: Participants (N = 148) were recruited from Leuven (Belgium) and Zaragoza (Spain): 74 patients with early/moderate glaucoma and 74 age-matched healthy controls. One eye was randomly selected for a macular scan using the Spectralis SD-OCT. The variables measured with the instrument's segmentation software were: macular nerve fiber layer (mRNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) volume and thickness along with circumpapillary RNFL thickness (cpRNFL). The new normative database of macular variables was used to define the cutoff of normality as the fifth percentile by age group. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC) of each macular measurement and of cpRNFL were used to distinguish between patients and controls. Results: Overall sensitivity and specificity to detect early-moderate glaucoma were 42.2% and 88.9% for mRNFL, 42.4% and 95.6% for GCL, 42.2% and 94.5% for IPL, and 53% and 94.6% for RNFL, respectively. The best macular variable to discriminate between the two groups of subjects was outer temporal GCL thickness as indicated by an AUROC of 0.903. This variable performed similarly to mean cpRNFL thickness (AUROC = 0.845; P = 0.29). Conclusions: Using our normative database as reference, the diagnostic power of inner macular layer thickness proved comparable to that of peripapillary RNFL thickness. Translational Relevance: Spectralis SD-OCT, cpRNFL thickness, and individual macular inner layer thicknesses show comparable diagnostic capacity for glaucoma and RNFL, GCL, and IPL thickness may be useful as an alternative diagnostic test when the measure of cpRNFL shows artifacts.status: publishe

Diagnostic ability of inner macular layers to discriminate early glaucomatous eyes using vertical and horizontal B-scan posterior pole protocols - Fig 4

<p><b>Receiver operating characteristic (ROC) curves for the macular (A) and peripapillary (B) parameters with the greater discriminating ability.</b> Abbreviations: mRNFL, macular retinal nerve fiber layer; mGCL, macular ganglion cell layer; pRNFL, peripapillary retinal nerve fiber layer.</p

Comparison of peripapillary choroidal thickness between healthy subjects and patients with Parkinson’s disease - Fig 4

<p>Representation of the mean peripapillary choroidal thickness (PPCT) for the 26×26 cube-grid centered on the optic disc for the three groups: the 40 right healthy eyes of the teaching population (left fig), the 40 right eyes of the healthy validating population (middle fig), and the 40 right eyes of the Parkinson´s disease (PD) patient group (right fig). Grey, cubes corresponding with the optic nerve head; yellow, mean PPCT <105 μm; green, mean PPCT ranging from 105 to 139 μm; blue, mean PPCT ranging from 140 to 174 μm; and orange, mean PPCT ≥175 μm. The temporosuperior choroid is the thickest, followed by superior, temporal, nasal, and inferior choroid.</p

Diagnostic ability of inner macular layers to discriminate early glaucomatous eyes using vertical and horizontal B-scan posterior pole protocols - Fig 1

<p><b>Representative optical coherence tomography (OCT) horizontal scan section of the macula of a normal (A and B) and early glaucomatous (C and D) left eye</b>. Macular ganglion cell layer (mGCL) is marked with two asterisks, and retinal nerve fiber (mRNFL) layer is marked with one asterisk, in Fig 1B (normal eye) and 1D (glaucomatous eye). The automated segmentation performed by the OCT Spectralis software between mRNFL and mGCL is shown with a light blue line, and between mGCL and inner plexiform layer is shown with a purple line. We can appreciate a slight thinning of mGCL in the glaucomatous eye, especially temporal to fovea. Optic nerve head (ONH) position and fovea (Fo) are indicated. The infrared image obtained with the Horizontal Posterior Pole protocol of Spectralis OCT is shown in the corner of each B-scan. The green lines of the infrared image delimit the square scanning area at the posterior pole.</p