PURPOSE:
To assess the accuracy of estimating intraocular pressure (IOP) at the end of cataract surgery and to suggest a method of verifying this value.
SETTING:
University hospital in a suburban area.
METHODS:
Sixty-nine eyes having phacoemulsification cataract surgery without complications were studied. In stage 1, the surgeon estimated IOP using digital pressure at the end of cataract surgery while a second investigator checked the actual IOP using a handheld tonometer. The estimated and true values were compared. In a second group of patients, the IOP was measured at the end of surgery in 30 eyes using a specifically designed tonometer, the Ocular Kasaby Barraquer 20/30 (OKBT-20/30) (Ocular Instruments, Inc.). The true values were then measured using the handheld tonometer to verify the accuracy of the OKBT-20/30.
RESULTS:
In stage 1, 37.7% of the estimates were outside the “acceptable” IOP range of 10 mm Hg or higher to 30 mm Hg or lower. Accuracy of estimates decreased toward the extremes of IOP. This suggests that eyes with IOP values outside the acceptable range are likely to be left as such at the end of surgery. In stage 2, when the IOP was measured with the new instrument and rechecked with the electronic tonometer, 93.3% of eyes had an IOP within the reference range of 20 to 30 mm Hg; 62.3% of eyes had an IOP within this range when estimated.
CONCLUSIONS:
Because the digital estimate can be misleading, the OKBT-20/30 tonometer or a similar device should be used routinely to ensure each eye is left with a desirable IOP at the end of cataract surgery.
