Topographical Correlation between Structural and Functional Impairment of the Macular Inner Retinal Layers in Multiple Sclerosis Eyes with a History of Optic Neuropathy

We investigated the potential correlation between morphological and functional parameters describing the rarefaction and dysfunction of retinal ganglion cells (RGCs), located in the macula, in multiple sclerosis eyes with a history of optic neuritis (MS-ON). A total of 19 MS-ON eyes from 19 MS patients (mean age: 44.16 ± 4.66 years; 11 females and 8 males), with a mean disease duration of 10.06 ± 6.12 years and full recovery of visual acuity, and 30 age-similar (mean age: 45.09 ± 5.08 years) healthy eyes were submitted for ophthalmological evaluation using swept-source optical coherence tomography (SS-OCT) and multifocal photopic negative response (mfPhNR) to study the structural and functional features of localized RGCs. Both GCL+ thickness (via SS-OCT) and response amplitude density (RAD) (via mfPhNR) measurements were obtained from annular regions and ETDRS sectors. Morphological and electrophysiological data from the control and MS groups were compared by using an ANOVA test. GCL+ values were correlated with the corresponding RADs derived from almost superimposable areas using Pearson's tests (p < 0.01). In MS-ON eyes, the mean values of macular GCL+-T and mfPhNR RAD detected in all rings and ETDRS sectors were significantly reduced (p < 0.01) when compared with control ones. In addition, when plotting the GCL+-T and mfPhNR RAD individual data from MS-ON eyes, we found statistically significant linear correlations (p < 0.01) when considering responses from both rings and sectors. In conclusion, in MS-ON eyes, a topographical correlation between structural and functional impairment of macular RGCs occurs.