Photoreceptor outer nuclear layer thickness changes in optic neuritis follow up.

BACKGROUND

Ganglion cell inner plexiform (GCIP) layer thinning following acute optic neuritis (ON) is well-known. However, the onset of changes in the outer retinal layers needs further study. In this study, we determine longitudinal changes in retinal layer thickness in ON.

METHODS

Thirty ON patients underwent optical coherence tomography (OCT) and visual function testing at baseline, one month, and 6 months.

RESULTS

Mean GCIPL thickness decreased at one month relative to baseline from 63.6 ± 7.5 μm to 57.3 ± 6.8 µm in 3 mm ring (P < 0.001). There were no significant changes in GCIPL thickness between one and 6 months (P = 0.42). Outer nuclear layer (ONL) thickness in the 6 mm macular area increased from 58.9 ± 5.8 µm to 63.2 ± 6.8 μm at one month (P < 0.001) and then decreased at six month (58.8 ± 5.8 µm) relative to one month, reaching the baseline thickness. While GCIPL thinning at 1 month correlated with baseline visual acuity, change in the central ONL thickness from baseline to month 1 predicted visual outcome at month 6 (r = 0.6, P = 0.001).

CONCLUSIONS

Following ON, transient changes occur in the photoreceptor nuclei layer and then revert to baseline. This finding could predict 6 month visual acuity after ON.