Optical Coherence Tomography in Multiple Sclerosis

Abstract

Optical coherence tomography (OCT) grew out of a convergence of rapid advancements in femtoseconds optics research and fiber optic commercial technology. The basic concept of OCT is to “see” into tissues using light echoes, analogous to the sound echoes of ultrasonography. Multiple A-scans are assembled into a B-scan two-dimensional image of the tissue of interest. Retina is an ideal tissue for evaluation by OCT, since the eye is designed to minimize light scattering through the anterior chamber and vitreous. OCT has had a significant impact on the field of multiple sclerosis, where it has allowed direct imaging of the myelin-free segments of axons and cell bodies of retinal ganglion cells. Together with precise functional measurements of the afferent visual system, the addition of robust structural measurements of retinal injury has allowed for an unprecedented ability to correlate clinical effects with the degree of neuronal loss. In addition, OCT has proven helpful to distinguish different forms of demyelinating disease, such as multiple sclerosis (MS) and neuromyelitis optica, and has provided ideal outcome measures in remyelination and neuroprotection trials.

Evaluation of optical coherence tomography angiography findings in patients with multiple sclerosis

“…Furthermore, group 2 patients showed a reduction in average GCL thickness as compared to the group 3 but with no statistical significance ( P = 0.381). The last finding agrees with other reports by Graves JS et al ,[ 18 ] Huang-Link YM et al ,[ 24 ] and Oberwahrenbrock T et al [ 26 ] who detected decreased GCL complex thickness even in patients without ON. GCL complex has functional superiority than RNFL.…”

“…The present study evaluated the RNFLT in all quadrants in the three groups and reported a significant reduction in MS patients when compared with the control group. Other studies done by Henderson AP et al ,[ 17 ] Graves JS et al ,[ 18 ] and Winges KM et al [ 19 ] detected similar results of RNFL thinning in MS patients. Significant reduction in average RNFL thickness in cases of group 1 compared to groups 2 and 3 ( P < 0.001).…”

“…The present study reported that the average GCL thickness was significantly reduced in patients of group 1 with P value 0.001; studies performed by Huang-Link YM et al ,[ 24 ] Graves JS et al ,[ 18 ] and Nguyen J et al [ 25 ] stated that the RNFL and GCL were thinner in MS patients. Still, the change was more pronounced in group 1.…”

Validation of inter-eye difference thresholds in optical coherence tomography for identification of optic neuritis in multiple sclerosis

“…GCIPL also shows superior structure-function correlation and neuroaxonal damage is detectable considerably faster in GCIPL than in pRNFL (Petzold et al, 2017;Gabilondo et al, 2015;Britze et al, 2017). Also, GCIPL is less prone to confounding by papillary oedema due to papillitis from acute ON (Graves, 2019).…”

Macular ganglion cell–inner plexiform layer thinning as a biomarker of disability progression in relapsing multiple sclerosis

“…7,8,25 Finally, GCIPL is the thickest layer in the macula with a large dynamic range which is less prone to the confounding influence of damage from past ON or swelling from acute ON. 26 Thus, mGCIPL is not prone to a floor effect as much as pRNFL. 7 Underlining this, we found mGCIPL ⩾1 µm per year strongly associated with occurrence of clinical events related to neurodegeneration such as EDSS progression (77%) and cognitive decline (79%), which significantly exceeded the strength of association found with pRNFL thinning (70% and 62%, respectively).…”