SPECTRALIS Glaucoma Module Premium Edition Clinical Mismatch between

SPECTRALIS® Glaucoma Module Premium Edition

Clinical Mismatch between clinically visible disc margin & SD-OCT-based disc margin SD-OCT BMO Clinically Visible Optic Disc Margin Image Courtesy Dr. Balwantray C. Chauhan, Halifax, Canada and Dr. Claude F. Burgoyne, Portland, USA.

Variable Rim Tissue § Internally oblique § Externally oblique § Non-oblique BMO Image Courtesy Dr. B. C. Chauhan, Halifax, Canada. Reis et al. Ophthalmology 119: 738 -747, 2012. Clinical disc margin

Clinical Disc Margin Conclusion § The clinical optic disc margin is hard to identify § In practice the clinician is looking at 3 different tissues when defining the disc margin § BMO (1), RPE tips (endings; 2), some aspect of border tissue of Elschnig (3) § The clinical disc margin is inconsistent as an anatomical landmark for the outer border of the rim § Each individual ONH can have regions of internally and / or externally oblique border tissues

Overestimation of Rim Tissue Consequences § Inconsistent definition of the disc margin can mean an underestimation of rim tissue. DM BMO § Using Bruch´s membrane opening (BMO) Image Courtesy Dr. B. C. Chauhan, Halifax, Canada. as a stable landmark provides a more accurate measurement of the ONH rim tissue.

Invisible BMO § Bruch's Membrane Opening is a consistent landmark, but it is usually clinically and photographically invisible. BMO Image Courtesy Dr. B. C. Chauhan, Halifax, Canada.

Geometric Orientation § Even if BMO is used as a stable landmark by SD-OCT, we still need to measure the neuroretinal rim in the correct geometric orientation. BMO-MRW Reis et al. Invest Ophthalmology Vis Sci. 53: 1852 -1860, 2012.

Basic Information Correct Rim Measurement § Neuroretinal rim measurement from BMO to nearest point on internal limiting membrane (ILM) BMO-MRW § Shortest distance measurement § Quantification of perpendicular cross section of nerve fibers exiting the eye Reis et al. Invest Ophthalmology Vis Sci. 53: 1852 -1860, 2012. § Taking into account their varying trajectory at all 48 points of measurement Cross Section of RNF

Current Reality § Current sectorial analysis is made with fixed horizontal and vertical axes on the image. AIF Horizontal (N/T) Axis AIF Vertical (S/I) Axis Acquired Image Frame (AIF)

Range of Variability of Fo. BMO Axes § Inter-individual variability in the axis connecting the Fovea and Bruch’s Membrane Opening (BMO) center < + 2° to - 18° * * Examples taken from the HDEng SPECTRALIS normative data collection

Anatomically Normalized Eyes § Anatomically consistent landmark in all human eyes § BMO is a true anatomic boundary of the RGC axons § BMOcentroid is the center of BMO § Fovea is the anatomic center of the retina § RGC axons organized relative to the Fo. BMO axis From: D. Hood et al. , Glaucomatous Damage in the Macula, Prog Retin Eye Res 2013; 1 -21.

Anatomic Positioning System - APS BMO Fovea xis A Fo. BMO -

Anatomic Positioning System - APS § Locates points in the eye using two fixed, structural landmarks § center of the fovea and § center of the Bruch’s Membrane Opening (BMO) § Automatic detection of landmarks during initial APS scan § Automatic alignment of scans relative to patient’s individual Fovea to - Bruch’s Membrane Opening (Fo. BMO) center axis § Consistent, accurate placement of subsequent scans and sectors for data analysis § Automatic adjustment for head tilt during acquisition

Anatomic Positioning System - APS Without SPECTRALIS APS Ø Same eye scanned on separate visits (no APS or Auto. Rescan) Ø Head tilt causes significant variability of classification results

Anatomic Positioning System - APS With SPECTRALIS APS Ø Consistent positioning for each individual’s anatomy Ø Two eyes with different anatomical positions of fovea relative to the center of the BMO (A and B) Ø Scan orientation automatically aligned along the individual’s Fo. BMO axis

Anatomic Positioning System - APS Ø Accurate geometric relations between nerve fiber defects can be established, which are observed in ONH, RNFL and the Posterior Pole Asymmetry Analysis Ø Easy correlation between analysis methods

Anatomic Positioning System - APS Advantages § Automatic § Consistent § Individual / Customized § Reliable

SPECTRALIS Glaucoma Module Premium Edition BMO Rim Analysis

SPECTRALIS Glaucoma Module Premium Edition Garway-Heath Sectors ° 40 Current Sectors Advantages 110° ° 40 40 ° 90° § Sector orientation aligned with nerve fiber bundle trajectory § Better structure-function correlation § Same eye – different sector distribution References: Garway-Heath DF et al. Mapping the Visual Field to the Optic Disc in Normal Tension Glaucoma Eyes. Ophthalmology 2000; 107: 1809– 1815.

SPECTRALIS Glaucoma Module Premium Edition Current Classification New Display Percentile: § Percentage of normal eyes have a rim this thin or thinner Actual thickness (Mean thickness value) Actual thickness (Percentile) § Different eyes – different displays § Remember HRT !!!

SPECTRALIS Glaucoma Module Premium Edition Internally oblique at nasal side Externally oblique at temp. side Within normal limits Borderline Outside normal limits BMO Overview

SPECTRALIS Glaucoma Module Premium Edition Progression

SPECTRALIS Glaucoma Module Premium Edition BMO Size: 1. 85 mm 2 BMO-MRW OU Report

SPECTRALIS Glaucoma Module Premium Edition BMO-MRW & RNFL Single Eye Report