The first specimen is the cross-section of the optic nerve head from a patient with poor vision (H&E stain). The second specimen came from another patient with similar condition but stained with alcian blue.

H&E

Alcian blue

• What are the features seen?


Answer
The first picture shows optic atrophy (note the depression of the optic nerve head and reduced 
nerve fibres) with cystic spaces (see picture below).
The second picture shows the presence of cystic spaces within the optic nerve. The tissues surrounding the cystic spaces are stained blue indicating the presence of mucopolysaccharides.

 
What is the diagnosis?

.
Answer
Schnabel's cavernous optic atrophy.
This condition is most commonly seen in patients 
with repeated epidoses of raised intraocular pressure. 
The mucopolysaccharides within the cystic spaces
came from the hyaluronic acid in the vitreous. It is
thought that the high intraocular pressure forces the vitreous into the optic nerve.
Similar changes, however, has been observed in 
ischaemic optic neuropathy such as in giant cell arteritis.