Understanding IOP Changes During Phacoemulsification Using Different Standpoints to Approach Fluidics: in Vivo Study
To compare different standpoints to approach fluidics measuring intraocular pressure (IOP) levels and fluctuactions in vivo during phacoemulsification.
Continuous IOP measurement was performed in four groups of 20 patients. In group 1 a standard coaxial phaco procedure (SCP), in group 2 a micro incision coaxial phaco (MCP) and in group 3 bimanual micro incision cataract surgery (B-MICS) were performed. In these groups agravity based fluidics was used. group 4 a MCP with an active fluidics was performed. To measure IOP the Codman Microsensor ICP Transducer was adopted.
Results show that a very high level of IOP is reached during surgery and remains so for several seconds. The average amount of time during which IOP remained above 60 mmHg was 106 ± 24 sec in SCP group, 112 ± 16 in MCP group and 141 ± 36 in B-MICS group (SCP vs MCP P= 0.12, SCP vs B-MICS P<0.01, MCP vs B-MICS P<0.001 ). The percentage of surgical time during which IOP remained above 60 mmHg was 41.5% in the SCP patients, 45.5% in MCP patients and 43% in B-MICS patients (42% for the whole material ). In the group of patients in whom an active fluidics was used the tension remained under the prefixed limit of 50 mmHg for the entire surgery in all the patients.
The results obtained in this study show that the problem of surgical intraocular hypertension during cataract surgery is present in all patients regardless the technique adopted if a gravity based fluidics is used. An active fluidics which adjusts the fluid inflow dynamically maintains the anterior chamber at a surgeon’s chosen IOP level.