Preliminary bench review suggests 4D ultrasound improves emulsification in dense cataract nuclei

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Frontiers in Medicine Published April 16, 2026 Medically reviewed April 25, 2026 DOI ↗ By Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic

Key Takeaway

Consider preliminary bench data favoring 4D ultrasound in dense nuclei, but await clinical validation.

This publication is an ex vivo bench pilot review evaluating the Alcon UNITY Cataract System using 4-dimensional (4D) ultrasound versus the Alcon CENTURION Vision System with torsional ultrasound. The study utilized a single human cataracta nigra nucleus divided into four fragments within an ex vivo cataracta nigra bench model. Primary and secondary outcomes included emulsification time, effective phaco time (EPT), cumulative dissipated energy (CDE), and qualitative video assessment of fragment behavior.

The review synthesizes results indicating that emulsification time was shorter with UNITY, with a mean of 12.0 s versus 43.5 s for the comparator. Effective phaco time (EPT) was lower with UNITY, showing a mean of 4.2 s versus 15.2 s. Cumulative dissipated energy (CDE) was also lower with UNITY, with a mean of 1.12 percent-seconds versus 15.01 percent-seconds. Qualitative assessment noted more continuous engagement with minimal chatter for UNITY, whereas CENTURION showed initial fragment repulsion and turbulence.

The authors acknowledge significant limitations, including the single-specimen model and the interpretation of console-derived endpoints as relative performance rather than equivalent physical energy delivery. They note the need for further studies using additional specimens and clinical cohorts. Safety data, including adverse events and tolerability, were not reported. The authors caution that these preliminary findings suggest 4D ultrasound mode might be associated with improved emulsification efficiency in ultra-dense nuclear material but should not be overstated as meaningful surgical benefit or equivalent physical energy delivery at this stage.

Study Details

Study typeSystematic review

EvidenceLevel 1

PublishedApr 2026

View Original Abstract ↓

Cataracta nigra, an extremely dense nuclear cataract, often requires prolonged ultrasound use during phacoemulsification, increasing the risk of corneal endothelial injury and incision-site thermal damage. We compared the Alcon UNITY Cataract System using 4-dimensional (4D) ultrasound with the Alcon CENTURION Vision System with torsional ultrasound in an ex vivo cataracta nigra bench model. A single human cataracta nigra nucleus was divided into four fragments; two fragments were emulsified with UNITY and two with CENTURION under identical user-selected console settings (35% power; IOP 36 mmHg; vacuum 450 mmHg; aspiration flow 30 mL/min). Endpoints included emulsification time, effective phaco time (EPT), cumulative dissipated energy (CDE), and qualitative video assessment of fragments behavior. In this single-specimen model, compared with CENTURION, UNITY showed shorter emulsification time (mean 12.0 s vs 43.5 s) and lower console-reported energy indices (mean EPT 4.2 s vs 15.2 s; mean CDE 1.12 percent-seconds vs 15.01 percent-seconds). Video review suggested more continuous fragment engagement with minimal chatter using UNITY, whereas CENTURION more often showed initial fragment repulsion and turbulence. Because EPT and CDE are console-derived, these findings should be interpreted as relative performance under matched user-selected settings rather than equivalent physical energy delivery. These preliminary findings suggest that the 4D ultrasound mode might be associated with improved emulsification efficiency compared to torsional mode in ultra-dense nuclear material. Further studies using additional specimens and clinical cohorts are needed to determine whether these bench findings translate into meaningful surgical benefit.