TY - JOUR
T1 - Hyperreflective dots in the avascular outer retina in relapsing-remitting multiple sclerosis
AU - Schmidt, Mathias Falck
AU - Pihl-Jensen, Gorm
AU - Torm, Marie Elise Wistrup
AU - Passali, Moschoula
AU - Larsen, Michael
AU - Frederiksen, Jette Lautrup
N1 - Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.
PY - 2023/4
Y1 - 2023/4
N2 - BACKGROUND: Hyperreflective granular elements with a transient presence in the retina can be detected non-invasively by optical coherence tomography (OCT). Such foci or dots may represent aggregates of activated microglia. However, in multiple sclerosis an increased number of hyperreflective foci has so far not been demonstrated in the intrinsically hyporeflective and avascular outer nuclear layer of the retina where there are no fixed elements in healthy eyes. Therefore, the present study intended to investigate the presence of hyperreflective foci in the outer nuclear layer in patients with relapsing- remitting multiple sclerosis (RRMS) by using a high-resolution OCT scanning protocol.METHODS: This cross-sectional exploratory study examined 88 eyes in 44 RRMS patients and 106 eyes in 53 age- and sex-matched healthy subjects. None of the patients had any sign of retinal disease. All patients and healthy subjects each underwent one session of spectral domain OCT imaging. A total of 23,200 B-scans extracted from 8 × 8 mm blocks of linear B-scans at 60 μm intervals were analysed for hyperreflective foci in the outer nuclear layer of the retina. Analyses were made of the total block scan and a circular 6-mm diameter fovea-centered field in each eye. Multivariate logistic regression analysis was used to assess associations between parameters.RESULTS: Hyperreflective foci were observed in 31 out of 44 (70.5 %) multiple sclerosis patients compared to 1 out of 53 (1.8%) healthy subjects (p < 0.0001). From analyses of the total block scans, the median number of hyperreflective foci in the outer nuclear layer was 1 (range 0-13) in patients and 0 (range 0-2) in healthy subjects (p < 0.0001). In total, 66.2% of all hyperreflective foci were located within 6 mm of the center of the macula. There was no detectable association between the presence of hyperreflective foci and retinal nerve fiber layer or ganglion cell layer thickness.CONCLUSION: Hyperreflective granular foci in the avascular outer nuclear layer of the retina seen by OCT were almost completely absent in healthy subjects, whereas they were found, albeit at low density, in the majority of patients with RRMS. Hyperreflective foci can be repeatedly examined by non-invasive means and without pupil dilation, which opens a new field of investigation of infiltrating elements in an unmyelinated part of the central nervous system.
AB - BACKGROUND: Hyperreflective granular elements with a transient presence in the retina can be detected non-invasively by optical coherence tomography (OCT). Such foci or dots may represent aggregates of activated microglia. However, in multiple sclerosis an increased number of hyperreflective foci has so far not been demonstrated in the intrinsically hyporeflective and avascular outer nuclear layer of the retina where there are no fixed elements in healthy eyes. Therefore, the present study intended to investigate the presence of hyperreflective foci in the outer nuclear layer in patients with relapsing- remitting multiple sclerosis (RRMS) by using a high-resolution OCT scanning protocol.METHODS: This cross-sectional exploratory study examined 88 eyes in 44 RRMS patients and 106 eyes in 53 age- and sex-matched healthy subjects. None of the patients had any sign of retinal disease. All patients and healthy subjects each underwent one session of spectral domain OCT imaging. A total of 23,200 B-scans extracted from 8 × 8 mm blocks of linear B-scans at 60 μm intervals were analysed for hyperreflective foci in the outer nuclear layer of the retina. Analyses were made of the total block scan and a circular 6-mm diameter fovea-centered field in each eye. Multivariate logistic regression analysis was used to assess associations between parameters.RESULTS: Hyperreflective foci were observed in 31 out of 44 (70.5 %) multiple sclerosis patients compared to 1 out of 53 (1.8%) healthy subjects (p < 0.0001). From analyses of the total block scans, the median number of hyperreflective foci in the outer nuclear layer was 1 (range 0-13) in patients and 0 (range 0-2) in healthy subjects (p < 0.0001). In total, 66.2% of all hyperreflective foci were located within 6 mm of the center of the macula. There was no detectable association between the presence of hyperreflective foci and retinal nerve fiber layer or ganglion cell layer thickness.CONCLUSION: Hyperreflective granular foci in the avascular outer nuclear layer of the retina seen by OCT were almost completely absent in healthy subjects, whereas they were found, albeit at low density, in the majority of patients with RRMS. Hyperreflective foci can be repeatedly examined by non-invasive means and without pupil dilation, which opens a new field of investigation of infiltrating elements in an unmyelinated part of the central nervous system.
KW - Hyperreflective foci
KW - Optical coherence tomography, Relapsing-remitting multiple sclerosis
KW - Outer nuclear layer
KW - Retina
KW - Retinal infiltration
UR - http://www.scopus.com/inward/record.url?scp=85150043912&partnerID=8YFLogxK
U2 - 10.1016/j.msard.2023.104617
DO - 10.1016/j.msard.2023.104617
M3 - Journal article
C2 - 36940613
SN - 2211-0348
VL - 72
JO - Multiple Sclerosis and Related Disorders
JF - Multiple Sclerosis and Related Disorders
M1 - 104617
ER -