Occlusion Break Surge Performance of a Next Generation Phacoemulsification System
Kevin M Miller1, Ali Aboughaida2, David Dyk2
1University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Journal of Cataract and Refractive Surgery
|April 1, 2026
Summary
The UNITY® Vitreoretinal Cataract System (UVCS) demonstrated significantly lower occlusion break surge volumes compared to the CENTURION® Vision System with Active Sentry™ (CAS). This finding suggests UVCS may enhance surgical safety by reducing risks like posterior capsule rupture.
Area of Science:
- Ophthalmology
- Medical Devices
- Surgical Technology
Background:
- Cataract surgery requires precise control of intraocular pressure (IOP) to ensure patient safety.
- Sudden fluidic shifts, known as occlusion break surge volumes, can occur during cataract surgery, potentially leading to complications.
- Comparing the fluid dynamics of different phacoemulsification systems is crucial for advancing surgical techniques.
Purpose of the Study:
- To quantitatively compare the occlusion break surge volumes between the UNITY® Vitreoretinal Cataract System (UVCS) and the CENTURION® Vision System with Active Sentry™ (CAS).
- To evaluate the impact of varying intraocular pressures, vacuum limits, and aspiration flow rates on surge volumes for both systems.
Main Methods:
- An experimental study utilizing an eye model with average human eye compliance.
- Testing was conducted across a range of intraocular pressures (IOPs) from 20 to 80 mmHg, vacuum limits from 300 to 650 mmHg, and aspiration flow rates of 20 and 40 cc/min.
- A second-order polynomial model was employed to analyze and compare data, particularly at a target IOP of 20 mmHg.
Main Results:
- The UNITY® Vitreoretinal Cataract System (UVCS) exhibited mean occlusion break surge volumes that were 44% lower than those of the CENTURION® Vision System with Active Sentry™ (CAS) across common settings.
- At a flow rate of 40 cc/min and an IOP setpoint of 20 mmHg, UVCS demonstrated an average surge volume decrease of 46% across all tested vacuum limits.
- The largest mean surge volume for UVCS was 48 µL, compared to 75 µL for CAS, representing 19% and 30% of average human phakic anterior chamber volume, respectively.
Conclusions:
- The UNITY® Vitreoretinal Cataract System (UVCS) consistently produced lower mean occlusion break surge volumes compared to the CENTURION® Vision System with Active Sentry™ (CAS).
- These findings suggest that UVCS may offer surgeons enhanced confidence when operating at lower IOPs.
- The reduced surge volumes associated with UVCS may potentially lower the risk of posterior capsule rupture, particularly in challenging cataract surgeries.
