Role of hemodilution
Horst Helbig (St. Gallen)
Retinal vein occlusion is a common ocular disease with variable visual
prognosis, leading in many cases to permanent loss of vision. Isovolemic
hemodilation is a treatment option with a convincing theoretical
concept. Lowering
the hematocrit reduces blood viscosity and improves microcirculation.
This effect overcompensates the reduced oxygen-carrying capacity
of hemodilution. In animal experiments an increase of retinal and
optic nerve oxygen tension has been measured
after hemodilution. Most randomized controlled clinical trials have
shown a positive effect
of isovolemic hemodilution on visual prognosis in retinal vein occlusion
with a very low incidenceof serious side effects. Thus, isovolemic
hemodilution
still is an important therapeutic option for retinal vein occlusion
against which other new modalities should be tested, regarding effectiveness
as well as complications of treatment.