Morphological changes of the retrobulbar optic nerve and its meningeal sheaths in glaucoma

This work focuses on the possible remodeling of the intraorbital portion of the optic nerve and its meningeal sheaths in glaucoma. The bulbar segments of the orbital optic nerve portion from 25 donors with glaucoma (M:F = 8:17; mean age +/- SD 85 +/- 11 years) and 25 controls (M:F = 14:11; mean age +/- SD 81 +/- 8 years) were formalin fixed, paraffin embedded and sectioned in series. Sections were stained with PAS, Masson trichrome and CD68, and examined for the following parameters: (1) diameter of the optic nerve; (2) thickness of the pia mater; (3) distance between dura mater and pia mater; (4) occurrence and amount of meningothelial cell nests in the subarachnoid space, and (5) presence and number of corpora arenacea. The mean diameter of the optic nerve was decreased in the glaucoma group when compared to the controls (2.9 +/- 0.5 vs. 3.3 +/- 0.5 mm; p < 0.01). The thickness of the pia mater was increased in the glaucoma group (0.1 +/- 0.04 vs. 0.09 +/- 0.03 mm, p < 0.05). Presence and number of corpora arenacea did not differ between the groups. Occurrence and amount of meningo- thelial cell nests in the subarachnoid space were however significantly increased in glaucoma (p < 0.02). Whether this observation is glaucoma specific deserves further investigation.