Table 4.

Proposed sample sizes (n per trial arm) for hypothetical 6-month clinical trial of neuroprotection in optic neuritis using ganglion cell layer plus inner plexiform layer as an outcome measure

Effect Size	20%	30%	40%	50%	60%
80% power	258	119	68	44	31
85% power	295	136	78	51	36
90% power	346	159	92	59	42

Effect size was defined as the per cent reduction of the observed mean change from baseline to 6 months.