Choroidal ganglion cell changes in human glaucomatous eyes

Choroidal ganglion cells (CGC) are an important source of vasodilative innervation of the posterior ciliary arteries, which also supplies the lamina cribrosa region of the optic nerve. The purpose of this study was to investigate whether CGC undergo quantitative and morphologic changes in human glaucomatous eyes.

Twenty-five human glaucomatous eyes (15 with primary open angle glaucoma, 10 with pseudoexfoliation glaucoma) and 38 normal eyes (31 age-matched) were investigated. Scleral and choroidal whole mounts were stained for NADPH diaphorase, the CGC quantified in the outer and inner choroid and in the different quadrants separately, and the diameter of the CGC measured. Serial semi- and ultrathin sections were studied by light and electron microscopy.

In glaucomatous eyes, the total number of CGC was significantly decreased. The most striking loss of CGC was found in the temporal quadrant adjacent to the optic nerve, where only single CGC persisted. The remaining CGC showed a normal ultrastructural appearance but a shift toward larger cells.

Smaller CGC and those directly adjacent to the optic nerve seem to be most susceptible to the yet unknown pathogenetic factors responsible for this CGC loss. Since the most pronounced loss of CGC occurred in the vicinity of the optic nerve it is tempting to speculate that the vasodilative regulation of the vessels supplying the lamina cribrosa region is impaired in eyes with POAG.