Change Of Pulsatile Ocular Blood Flow During Phacoemulsification Surgery With High Irrigative Pressure

Purpose: To investigate the change of POBF and relative parameters during steps of phacoemulsification with high irrigative pressure in vivo.Methods: A total of 77 patients with cataract who underwent phacoemulsification were included. All the patients were divided into 4 groups based on coexisting with different diseases. The 4 groups included simple cataract group(C group,23 cases),cataract with glaucoma group(G group,22 cases) ,cataract with hypertension group(H group,19 cases),cataract with diabetes mellitus group(D group,13 cases).The POBF was assessed by POBF analyzer(OBFA, Paradigm corporation, USA) and measured 3 times totally : before the surgery as baseline, the phacoemulsification step (bottle height: 120cm,vaccum: 280mmHg) and I/A step(bottle height: 110cm, vaccum:450mmHg). The blood pressure (BP) and heart rate were recorded by ECG monitor at the same time when POBF was measured.Results: Compared with baseline, POBF of all 4 groups decreased at the phacoemulsification step. And continue to decrease further at the I/A step except G group. There were statistically significant difference between baseline and the I/A step in C group, H group and D group (P<0.001, P<0.001, P=0.035 ). The highest IOP measured in the 3 steps all appeared in the phacoemulsification step in the 4 groups, between 54~60mmHg. Compared with baseline, IOP measured in the 2 steps in surgery increased statistically significant (P<0.05) in 4 groups except G group (P<0.05). POBF was found to decrease with increasing age or IOP. And POBF increased as heart rate or systolic blood pressure increased.Conclusion: The present study indicates that as IOP rises in the phacoemulsification surgery, POBF continues to decrease. It suggests that phacoemulsification surgery may cause ocular ischemic with high irrigative pressure.