Ganglion cell analysis in acute optic neuritis.

Background: Optic neuritis has a diagnostic and prognostic significance in predicting the development of multiple sclerosis. Optical coherence tomography is being increasingly used to detect and monitor axonal damage in MS by measuring the retinal nerve fiber layer (RNFL). However, RNFL can be affected by edema and inflammation and obscure early axonal damage.

Objective: To study the pattern of change in the ganglion cell and inner plexiform layer compared to retinal nerve fibber layer in acute optic neuritis using spectral domain OCT.

Methods: Ten patients with acute optic neuritis were followed prospectively for 6 months with spectral domain optical coherence tomography. A group of 40 of eyes of 20 healthy controls was used for baseline comparison.

Results: The ganglion cell and inner plexiform layer (GCIPL) was significantly lower (thinner) at onset in patients' affected (p=0.009) eyes. Both RNFL and GCIPL were significantly lower in affected eyes at 6 months (p=0.012 and p=0.007) respectively compared to baseline.

Conclusion: The GCIPL is probably more sensitive index of axonal loss than the RNFL in acute optic neuritis and could be a better index to detect neurodegeneration in multiple sclerosis. This can helpful in estimating early axonal loss and can potentially be used in therapeutic trials of neuroprotective drugs.