Purpose To measure intraocular pressure (IOP) elevation 6 and 24 hours after phacoemulsification in patients with glaucoma and to investigate the efficacy of brimonidine tartrate 0.2% in preventing IOP rise on the first postoperative day following cataract surgery. Methods In this prospective randomized single-masked study, 86 eyes of 78 patients with well-con-trolled open-angle glaucoma were scheduled for phacoemulsification surgery. Patients were randomly assigned into 2 groups. Group A received 1 drop of brimonidine tartrate 0.2% and group B, which served as a control group, received 1 drop of artificial tears. Intraocular pressure was measured at baseline, before surgery, and 6 and 24 hours postoperatively. Results Within each group, we found a statistically significant difference in IOP between baseline and 6 hours postoperatively (p<0.01) and between 6 and 24 hours (p<0.01). There was no statistically significant difference between baseline IOP and 24-hour values. Comparing the 2 groups, there was no statistically significant difference in preoperative and 24-hour postoperative IOP. Six hours after surgery, the mean IOP in the brimonidine group was 18.52±4.58 mmHg, compared with 20.86±3.79 mmHg in the control group. Treatment with brimonidine tartrate 0.2% significantly reduced postoperative IOP elevation 6 hours following cataract extraction (p=0.009). Conclusions Patients with medically well-controlled glaucoma may experience a substantial increase in IOP shortly after phacoemulsification surgery. Instillation of brimonidine tartrate 0.2%, although it significantly reduced IOP elevation following cataract operation, did not completely prevent IOP spikes.
To evaluate the effect of routine phacoemulsification in corneal viscoelastic properties determined by corneal hysteresis (CH) and central corneal thickness (CCT) and to explore the impact of phaco energy on the above parameters.Forty-one eyes of 41 patients undergoing cataract surgery were enrolled in this prospective study. CH and CCT were measured preoperatively, 1 day and 1 week postoperatively. CCT measurement was performed using a non-contact optical pachymeter followed by ocular response analyzer (ORA) examination. Intraoperatively ultrasound time, average phaco power and effective phaco time (EPT) were recorded.Mean CH was 10.05±1.86 mmHg preoperatively, 8.25±1.85 mmHg 1 day and 9.12±1.37 mmHg 1 week postoperatively (p<0.001). The mean CCT was 534±37.33 μm preoperatively, 592.22±46.34 μm 1 day and 563.21±49.84 μm 1 week postoperatively (p<0.001). CCT and CH were statistically significantly correlated preoperatively (p=0.01, r=0.396). This correlation was not sustained on the first postoperative day (p=0.094, r=0.265) and was re-established 1 week postoperatively (p=0.002, r=0.568). On the first postoperative day, the CCT increase was positively correlated with EPT (p=0.009, r=0.404), which was not found between CH change and EPT.Structural corneal alterations following cataract surgery resulted in a statistical change in CH and CCT. These two parameters responded in a different manner that clearly demarcates their different nature. On the first postoperative day, CCT increase was correlated at a statistically significant level with intraoperative EPT. This correlation was not found with CH reduction. Other factors, besides cornea oedema or phacoemulsification energy, could be responsible for this CH modification.