Medically reviewed by Dr. Kimberly Langdon Cull, M.D. on Oct. 4, 2023
A recent study found that inner retinal layer atrophy, assessed using optical coherence tomography, was associated with worsening ambulation in patients with primary progressive multiple sclerosis. This indicates that optical coherence tomography can be utilized for monitoring disability progression in multiple sclerosis patients.
Disability progression in individuals with multiple sclerosis (MS) is represented by an increase in the expanded disability status scale (EDSS) and worsening walking ability, or ambulatory functional score (AS). Validated and reliable surrogate markers such as optical coherence tomography (OCT) are useful in determining the progression of disability and are independent of AS and EDSS deterioration.
This study aimed to investigate the annual inner retinal layer changes in MS patients versus healthy controls using OCT and identify their association with worsening AS in MS patients. The findings are published in the International Journal of Molecular Sciences.
Participants Characteristics
The study cohort comprised 57 primary progressive MS (PPMS) patients with 108 eyes, 62 relapse-remitting MS (RRMS) patients with 114 eyes, and 61 healthy controls with 121 eyes. The median follow-up time for MS patients was three years (IQR: 2–5). The mean age, calculated at baseline OCT, of healthy controls, PPMS, and RRMS patients was 36.64 ± 12.82, 54.12 ± 10.68, and 37.19 ± 10.75 years, respectively.
Cross-Sectional Analysis of Retinal Layers
The thickness of the peripapillary retinal nerve fiber layer (pRNFL) layer was significantly decreased in MS patients compared to healthy controls at baseline OCT. The volume of ganglion cells and inner plexiform layer (GCIP) and total macular volume (TMV) were also significantly reduced in MS patients. There were no significant differences in the PPMS and RRMS cohorts when compared for retinal layers at baseline OCT. PPMS patients had a greater thickness of pRNFL compared to RRMS patients.
Longitudinal Analysis of Retinal Layers
The longitudinal analysis of retinal layers indicated a significantly greater annual decrease in the pRNFL thickness in MS patients compared to healthy controls. The mean annual change in the inner nuclear layer (INL) volume was significantly different between healthy controls and MS patients. RRMS patients had a greater decrease in GCIP volume compared to the PPMS patients.
Macular Layer Degeneration and Ambulatory Function
Of the 37 PPMS patients, 16 had deteriorated ambulation functional scores. There were no significant differences between PPMS and RRMS patients who reported stable AS when assessed for OCT parameters, except for a significantly increased relative GCIP atrophy rate in the RRMS cohort. Compared to stable PPMS patients, PPMS patients with AS deterioration demonstrated a significantly greater annual decrease in the GCIP, TMV, and outer nuclear and outer plexiform layer (ONPL), which was associated with an increased risk of AS deterioration.
Source
Gernert, J. A., Böhm, L., Starck, M., Buchka, S., Kuempfel, T., Kleiter, I., & Havla, J. (2023). Inner Retinal Layer Changes Reflect Changes in Ambulation Score in Patients with Primary Progressive Multiple Sclerosis. International Journal of Molecular Sciences, 24(16), 12872. https://doi.org/10.3390/ijms241612872
