Progressive loss and cytological changes are attenuated in ON neurons. Neuronal loss in OAH (b) was already severe (-78.8%) at the early phase, while it was less severe in DL (-25.8%) with subsequent progression to -78.0% at the advanced stage. Early loss (-32.1%) and subsequent progression (-47.2%) were attenuated in ON (Figure 3
c). in DL (a) -but mildly to moderately in ON (c). Neuronal loss preferentially involved large neurons in DL (d) and small neurons in OAH and ON (e, f). Size reduction of surviving neurons was apparent in DL (g, j), while their size increase was significant in OAH at the early phase (h, k), partly explained by preferential loss of small neurons (e). Neuronal size of surviving ON neurons was stable (i, l). In spite of this variability in size change at the early phase, significant decrease in CI was a consistent feature shared between these groups (m-o). (-): neurons without inclusions, (+): neurons with inclusions. p: p value.