Retinal structural damage was observed in neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) patients with demyelinating transverse myelitis (TM) but without optic neuritis (ON) in a study published in Neurological Sciences.
The mean retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses were significantly lower compared to healthy controls even while visual function was well preserved. Patients with myelin oligodendrocyte glycoprotein-associated disease (MOGAD) also had a significant reduction in RNFL—but not GCIPL, which is more sensitive to subtle changes in thickness—compared to healthy controls.
While RNFL thickness was reduced compared to healthy controls, it was not significantly different between the 3 different disease groups. The GCIPL was significantly thinner in patients with NMOSD and MS compared to patients with MOGAD, however.
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“Our study demonstrated disease entity-based variation of retina-microstructural damage in demyelinating TM patients. Retina-structural damage was apparent in TM patients with AQP4-IgG-positive NMOSD and MS; however, damage was not obvious in MOG antibody-positive TM patients,” the study’s authors concluded.
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The lack of GCIPL thinning in MOGAD patients indicates that no structural damage had occurred in this patient group. The difference in RNFL thickness may have been due to the small sample size of the MOGAD patient group, according to the authors.
The myelin oligodendrocyte glycoprotein (MOG) is not present in the human retina while the aquaporin-4 (AQP4) channels are highly expressed in the Müller-cells of the inner retina, which may explain why damage was not apparent in MOGAD patients with TM compared to NMOSD patients with TM.
When comparing same disease patients with TM to those with ON, the RNFL and GCIPL were thinner in patients with ON. Visual acuity and mean deviation were worse in NMOSD patients with ON compared to TM but no difference was observed between the ON and TM groups for MOGAD and MS patients.
A total of 97 patients and 65 healthy controls were recruited for the study. The patients included 36 NMOSD patients positive for AQP4-IgG (23 with ON and 13 with TM), 35 with MOGAD (32 with ON and 3 with TM), and 26 with MS (13 with ON and 13 with TM).
Reference
Lee JH, Moon Y, Kwon YN, Shin JH, Kim SM, Jung JH. Changes of retinal structure and visual function in patients with demyelinating transverse myelitis. Neurol Sci. Published online August 8, 2022. doi:10.1007/s10072-022-06315-1
