Vitreoretinal reactions and persistent hyaloid vessels.

In cases with persistent primary vitreous in full-term infants there were vitreoretinal reactions including vitreoretinal anastomoses of blood vessels, vitreoretinal strands, traction folds of the retina, avascular retinal areas, hypoplasia of retinal blood vessels, rarefaction of retinal ganglion cells, and ischaemic structural changes of the retina. New vessel formation on the surface of avascular retinal areas was supplied from persistent hyaloid blood vessels. This finding may be of some importance in explaining those cases histologically resembling classical retrolental fibroplasia with no history of prematurity or oxygen treatment.