Is the ganglion cell layer thickness to macular thickness ratio a new biomarker for multiple sclerosis?

Ganglion cell layer thickness (GCLT)-to-total macular thickness (MT) is a new parameter that has not been studied in multiple sclerosis (MS) before. The current study aims to reveal the status of the GCLT-to-MT ratio in MS and its role in supporting the diagnosis of MS.

In this retrospective and cross sectional study, the medical records of the MS patients between January 2016 and December 2021 were reviewed. Age-sex matched healthy control group was generated. Demographic and clinical data recorded. All participants were examined using a spectral-domain optic coherence tomography (OCT) device. Retinal layers, choroidal thickness (CT) was recorded. GCLT-to-MT ratio was calculated.

A total of 74 eyes of 37 MS (9 male,28 female) patients and 82 eyes of 41 control (13 male, 28 female) were included in the study. The mean age was 37 ± 9.0 (years) in MS group. The MS patients and the control group were compared in terms of OCT parameters, CT was thicker at all regions in MS patients (p < 0.001). Macular thickness, GCLT, and inner plexiform layer thickness (IPLT) were thinner than the control group (p < 0.05). For distinguishing MS patients from healthy subjects, AUROC values for central GCLT/MT, temporal GCLT/MT, superior GCLT/MT, nasal GCLT/MT, and inferior GCLT/MT were 0.717, 0.689, 0.694, 0.733, and 0.740, respectively.

In conclusion MT, GCLT, and IPLT thickness were thinner in MS patients, regardless of optic neuritis. The AUROC values of GCLT/MT were high and GCLT/MT ratio may be a helpful modality in demonstrating retinal neurodegeneration in MS patients.