Intraocular pressure assessment in gas-filled eyes following vitrectomy

The accuracy and precision of tonometric methods in measuring intraocular pressure (IOP) was assessed in 24 eye-bank eyes subjected to pars plana lensectomy/vitrectomy and air-fluid exchange. Intraocular pressure was measured in masked fashion with a Perkins' applanation tonometer, pneumatic applanation tonometer; a mercury manometer served as a reference standard. Pneumatic tonometry underestimated actual IOP by as much as 25%, and Schiotz' indentation tonometry underestimated actual IOP by as much as 79%. Perkins' applanation tonometry was significantly more accurate in estimating actual IOP in gas-filled eyes than pneumatic tonometry or Schiotz' indentation tonometry.