Structural-visual functional relationships detected by optical coherence tomography in varying age-cohorts' patients with optic neuritis

Abstract

Aim: To assess the relationships of final best-corrected visual acuity (BCVA) and the optic nerve structural loss in varying age-cohorts of optic neuritis (ON) patients.

Methods: This is a retrospective, cross-sectional study. Totally 130 ON subjects (200 eyes) without ON onset within 6mo were included, who underwent BCVA assessment, peripapillary retinal nerve fibre layer (pRNFL) and macular segmented layers evaluation by optical coherence tomography (OCT).

Results: For the 0-18y cohort, the final BCVA (logMAR) was significantly better and less frequent recurrences than adult cohorts (P=0.000). The final BCVA (logMAR) in all age-cohorts of the ON patients had negative and linear correlations to the pRNFL thicknesses and macular retinal ganglion cell layer (mRGCL) volumes, when the pRNFL thicknesses were reduced to the thresholds of 57.2-67.5 µm or 0.691-0.737 mm³ in mRGCL volumes, respectively, with the strongest interdependence in the 19-40y cohort. The ON patients from varying age cohorts would be threatened by blindness when their pRNFL thicknesses dropped 36.7-48.3 µm or the mRGCL volumes dropped to 0.495-0.613 mm³.

Conclusion: The paediatric ON has best prognosis and young adult ON exhibits perfectly linear correlations of final vision and structural loss. The pRNFL and the mRGCL could be potential structural markers to predict the vision prognosis for varying-age ON patients.

Keywords: age-cohort; final visual acuity; linear correlations; optic neuritis; structural impairment.

Figure 1. Flowchart of the participants and the age-cohorts of the patients with optic neuritis

ON: Optic neuritis; OCT: Optical coherence tomography.

Figure 2. Final BCVA (logMAR) eyes affected by ON and the number of episodes of ON onsets in varying age-cohorts

A: The final VA in eyes affected by ON from the 0-18y cohort was much better than that of the 19-40y and the 41-70y cohorts. The episodes of ON onsets in the 0-18y ON cohort were less than those of the 19-40y and the 41-70y cohorts. BCVA: Best-corrected visual acuity; ON: Optic neuritis; VA: Visual acuity. ^aP<0.01.

Figure 3. pRNFL thicknesses and macular segmented layer volume alterations in age varying ON cohorts

A: Global pRNFL thicknesses in eyes affected by ON from the 0-18y cohort lost less than that of the 19-40y and the 41-70y cohorts; B: The mRNFL volumes in eyes affected by ON from the 0-18y cohort had a milder decrease than that of the 19-40y cohort; C: The mRGCL volumes in eyes affected by ON from the 0-18y cohort lost less than the other cohorts; D: The mIPL volumes in the eyes affected by ON from the 0-18y cohort lost less than the other cohorts; E: The mINL volumes went up with increased age; however, there were no significant differences in the three cohorts of ON patients. pRNFL: Prepapillary retinal nerve fibre layer; ON: Optic neuritis; mRNFL: Macular retinal nerve fibre layer; mRGCL: Macular retinal ganglion cell layer; mIPL: Macular inner plexiform layer; mINL: Macular inner nuclear layer. ^aP<0.01, ^bP<0.05.

Figure 4. Correlations between the final BCVA and pRNFL thicknesses and the macular segmented layer volumes in eyes affected by ON from the varying age-cohorts

The pRNFL thicknesses and all of the inner macular segmented layers volumes, except for the INL, were all negatively and linearly related to the final BCVA in the ON affected eyes from the 0-18y cohorts (A), the 19-40y cohorts (B) and the 41-70y cohorts (C). The pRNFL thicknesses and the RGCL volumes had stronger relations to the final BCVA, as compared with the mRNFL and the mIPL. Among them, the structural-functional linear correlations in the eyes affected by ON from the 19-40y cohort were more perfect than those of the other age-cohorts. BCVA: Best-corrected visual acuity; pRNFL: Prepapillary retinal nerve fibre layer; ON: Optic neuritis; mRNFL: Macular retinal nerve fibre layer; mRGCL: Macular retinal ganglion cell layer; mIPL: Macular inner plexiform layer; mINL: Macular inner nuclear layer.