Patients with neuromyelitis optica spectrum disorder (NMOSD) have sparser macula microvasculature regardless of the presence of optic neuritis (ON), according to a new study published in Multiple Sclerosis and Related Disorders.
The study found that the eyes of patients with NMOSD without ON had sparser inner macula vascular complex (IVC; P =.008) and superficial vascular plexus (SVC; P =.003) compared to healthy controls. Eyes with NMOSD and ON were also significantly sparser (P <.001) than healthy control eyes in the IVC and SVC, as well as the deep vascular plexus (DVC).
When comparing eyes with NMOSD with and without ON, the eyes with ON were significantly sparser in all 3 regions: IVC (P =.002), SVC (P =.001), and DVC (P =.04).
“We also showed that NMOSD eyes with and without optic neuritis had sparser microvasculature when compared with healthy controls; besides, NMOSD eyes with ON showed sparser microvasculature compared with eyes without ON,” the authors said. “Our current report suggests that microvascular changes in NMOSD patients develop independently of the incidence of ON.”
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The study also found that the microvascular sparsity was correlated with the duration of the disease, the frequency of ON, and reduced visual acuity. The IVC (P =.015) and SVC (P =.004) were inversely correlated with disease duration and all 3 regions (IVC, SVC, and DVC) showed a correlation with the frequency of ON.
While all 3 regions were correlated with reduced visual acuity in eyes with NMOSD and ON, eyes without ON were not correlated, however. While observing the macula microvasculature and structure of the eyes, the researchers found that the thicknesses of the macular ganglion cell-inner plexiform layer (GCIPL) and retinal nerve fiber layer (RNFL) were correlated with the microvasculature changes in patients with NMOSD.
The GCIPL was correlated with SVC and IVC in both patients with and without ON. RNFL thickness was correlated with DVC in patients with ON but with SVC and IVC in patients without.
A total of 75 participants were recruited for the study including 40 patients with aquaporin-4 seropositive NMOSD and 35 healthy controls. Five of the patients with NMOSD were excluded from the study due to either poor angiogram quality or an occurrence of ON within the last 6 months prior to evaluation.
Of the 35 patients with NMOSD, 6 had unilateral and 13 had bilateral ON while 13 patients did not have ON. This resulted in a total of 32 out of 70 eyes with NMOSD and ON.
Lang Y, Kwapong WR, Kong L, et al. Sparser macula microvasculature in neuromyelitis optica spectrum disorder occurs independently of optic neuritis. Mult Scler Relat Disord. Published online December 20, 2021. doi:10.1016/j.msard.2021.103470