Three-dimensional geometries representing the retinal nerve fiber layer in multiple sclerosis, optic neuritis, and healthy eyes

Purpose To represent and interpret the three-dimensional geometry and distribution of the axonal damage to the retinal nerve fiber layer (RNFL) in patients with multiple sclerosis (MS) compared with healthy subjects. To analyze alterations in RNFL morphology in eyes of MS patients with or without previous episodes of optic neuritis (ON). Methods MS patients (n=122) and age-matched healthy subjects (n=108) were enrolled in this observational cross-sectional study. The Spectralis OCT system (Heidelberg Engineering) was used to determine the circumpapillary RNFL thickness in both eyes of each participant. The 768 RNFL thickness measurements provided by the Spectralis OCT were used to evaluate thickness measurements in MS patients with or without antecedent ON and to design a three-dimensional reconstruction of the RNFL thickness representing the mechanobiologic tissue response to neurodegeneration caused by MS and ON episodes. Results RNFL thickness was decreased in MS patients, and higher in the MS group with previous ON. Statistical analysis and three-dimensional RNFL reconstruction revealed greater damage to the ganglionar cells in the superonasal RNFL area in MS eyes (101.77 µm in MS vs 125.47 µm in healthy subjects) and in the inferotemporal RNFL (119.05 µm in healthy eyes vs. 149.26 previous-ON MS eyes) in MS eyes with previous ON. Conclusion The three-dimensional representation of RNFL thickness based on measurements provided by the Spectralis OCT allows physicians to better observe damage in the temporal areas, especially in patients with previous ON.