Pur-pose. To detect the mechanism of intraocular pressure elevation du
ring hemodialysis. Methods. We measured intraocular pressure, as well
as serum osmolality and plasma CO2 pressure, every 30 min during hemod
ialysis, in 5 eyes with severely compromised aqueous outflow facility
(Group A) from 4 renal failure patients. The same measurements were re
peated on the same eyes using intravenous hyperosmotic Glyceol(R) to p
revent a rapid change in serum osmolality. We also measured the same p
arameters on 8 eyes with normal aqueous outflow facility (Group B) fro
m 5 patients. The mean +/- SE of percent changes in each parameter was
used for the statistical analysis Results. In Group A, the mean perce
nt change of intraocular pressure increased significantly after 90 min
, with the exception of the change at 180 min. The mean percent change
of serum osmolality decreased significantly after starting dialysis.
A negative correlation in the mean percent change of intraocular press
ure with serum osmolality was detected (r = -0.759, r < 0.0001). The a
dministration of intravenous hyperosmotic agent prevented significant
changes in not only serum osmolality but also intraocular pressure. In
Group B, the mean percent change in intraocular pressure showed no si
gnificant difference at any time, although the change in serum osmolal
ity decreased significantly. Conclusion. A remarkable rise in intraocu
lar pressure occurs during hemodialysis in eyes with an impaired aqueo
us outflow, when serum osmolality decreases rapidly.