NBEO Histology Practice Test

The main concept here is the direction of degeneration along a neuron. When the cell body is damaged and degeneration travels away from the cell body down the axon toward its terminals, that is orthograde (anterior/anterograde) degeneration. Panretinal photocoagulation damages retinal tissue, including retinal ganglion cells. If the retinal cell bodies are affected, the degenerative process moves down the axon into the optic nerve toward the brain, which fits orthograde degeneration. Retrograde degeneration would move toward the cell body, which isn’t the typical pattern produced by laser injury to the retina. So the optic nerve degeneration pattern after PRP is orthograde.