Intraoperative intraocular pressure fluctuation during standard phacoemulsification in real human patients

Abstract

Introduction.To evaluate the results of the fluctuations of intraocular pressure (IOP) and calculated mean ocular perfusion pressure (MOPP) during the usual steps of standard phacoemulsification. Methods. Nine human eyes were evaluated. The IOP was measured indirectly by electronic applanation tonometer. The MOPP was calculated using the systolic blood pressure (SBP), the diastolic blood pressure (DBP) and the IOP: MOPP = 2/3x[DBP + 1/3x(SBP -DBP)] -IOP. The operations were performed with the INFINITI ® Vision System: main incision 2.2 mm, coaxial handpiece, 2 paracenteses 1.1 mm, bimanual irrigation/aspiration, bottle height 100 cm. As ocular viscoelastic device (OVD) Hypromel 2.5% (UNIMED) was used. Results. The initial and final IOPs were 17-30 Torr (median 18) and 6-16 Torr (median 8), respectively. The IOP values oscillated between 4 and 63 Torr during the procedure. The highest values of the IOP were achieved at the beginning of phacoemulsification (from 42 to 63 Torr). The maximum pressure higher than 50 mmHg and 60 mmHg was found in 89% and 30% of cases, respectively. The mean ocular perfusion pressure (MOPP) at the beginning of the procedure was 46.4-67.0 (median 53.3) and 0.4-42.0 (median 19.3) during the maximum intraocular pressure. Conclusions. Measured IOP as well as MOPP varied in all normal steps of real phacoemulsification. High values of intraoperative IOL induced by irrigation may compromise the intraocular perfusion. These fluctuations may induce impairment of the optic nerve perfusion, as well as retina, or choroid.

Injection time related to intraocular pressure using a CO2 driven preloaded injector: An experimental laboratory study

“…pressure fluctuations between 9-400 mmHg occur during cataract surgery [8][9][10][11][12][13]. Short-term pressure peaks of up to 400 mmHg have been observed during hydrodissection.…”

“…Zhao et al [8] used an intracameral pressure sensor in 25 patients during cataract surgery and found the IOP between 13 and 96 mm Hg. In another in vivo study, which included 9 patients, the IOP of 10-50 mm Hg was measured with the electronic applanation tonometer [10]. Khng et al [9] conducted an experimental study in 3 cadaver eyes using a sensor in the vitreous cavity and found that the IOP was above 60 mm Hg 48-85% of the time during cataract surgery.…”

“…Khng et al [9] conducted an experimental study in 3 cadaver eyes using a sensor in the vitreous cavity and found that the IOP was above 60 mm Hg 48-85% of the time during cataract surgery. The IOP at the start of lens injection is between 18-55 mmHg depending on the study [9,10].…”

“…In this study we have chosen the three groups to test the injector for reliability at different IOPs. The IOP in group 1 and 2 with 20 and 50 mmHg is chosen as it occurs before implantation of the IOL [9,10] during cataract surgery. For group 3 a pressure of 80 mmHg was chosen to test the reliability of the injector at high intraocular pressure.…”

“…The IOP is normally between 9-21 mmHg [6,7]. During a routine cataract surgery, the IOP can fluctuate from 9 to over 400 mmHg [8][9][10][11][12][13]. Adding very small volumes into the eye greatly affects intraocular pressure [14].…”