Abstract
Purpose: :
To investigate the feasibility of measuring intraocular pressure (IOP) in vitreous humor through the pars plana and its correlation to the value measured in the anterior chamber.
Methods: :
For experiment, a cadaver eye was immobilized in a Styrofoam and a water column was connected to the anterior chamber through a needle (26 gauge), while the induced vitreous pressure was measured by a pressure sensor attached via another needle (26 gauge) inserted at pars plana.
Results: :
Figure 1 shows measurement results indicating a strong correlation between pressures measured at the anterior chamber and in the vitreous cavity through the pars plana. Measurements were carried out on two eyes and the vitreous pressure was monitored both while increasing and decreasing the bottle height and anterior chamber pressure. From these experiments, one can write:vitreous pressure = 0.981*( interior chamber pressure)+0.42with total correlation equals to 0.96 and standard deviation of 0.559 which shows vitreous pressure is correlated well with the anterior chamber pressure.
Conclusions: :
Vitreous chamber pressure measurement is an accurate indicator of the anterior chamber IOP. Measurement through pars plana is envisioned as a possible alternative site for continuous IOP monitoring using small wireless transponders.Figure 1: Measurement results showing a strong correlation between pressures measured at the anterior chamber and vitreous through pars plana.
Keywords: intraocular pressure • vitreous