Trial Comparing miLOOP Device Assisted Phacoemulsification vs Standard Surgery for Dense Cataracts: Effects on Endothelial Cell Loss, Energy Use, and Vision Recovery

Despite ongoing advances in phacoemulsification technology, surgical management of advanced dense nuclear cataracts remains technically demanding. These cataracts are frequently associated with increased ultrasound energy delivery, prolonged phacoemulsification time, and heightened mechanical manipulation within the capsular bag, all of which may contribute to increased corneal endothelial cell loss, postoperative corneal edema, and a higher incidence of intraoperative complications. In addition, conventional nuclear disassembly techniques used in dense cataracts often generate centrifugal forces during fracture propagation, which may impose stress on the zonular-capsular complex and increase the risk of capsular or zonular compromise.

The miLOOP Lens Fragmentation Device is a single-use microinterventional instrument developed to facilitate endocapsular lens nucleus disassembly prior to phacoemulsification. The device consists of a nitinol microfilament loop that exploits the shape-memory properties of the alloy to allow controlled expansion and constriction within the capsular bag. When deployed circumferentially around the lens nucleus and subsequently constricted, the loop applies centripetal cutting forces directed inwardly, enabling full-thickness nuclear segmentation independent of nuclear density. This mechanism permits mechanical fragmentation of the nucleus while minimizing the need for ultrasonic energy and reducing outward stress on the capsular bag and zonular fibers.

Early clinical experience and comparative studies have suggested that miLOOP-assisted lens fragmentation may reduce ultrasound energy requirements and improve intraoperative efficiency, particularly in eyes with advanced cataracts. Reported findings include reductions in cumulative dissipated energy and favorable intraoperative safety profiles. However, the existing body of evidence is limited predominantly to retrospective analyses or small prospective cohorts, and there remains a relative paucity of randomized controlled data. In particular, prospective evidence evaluating corneal endothelial cell loss and postoperative corneal recovery following miLOOP-assisted phacoemulsification in dense cataracts is limited.

This study is designed as a prospective, single-masked, randomized controlled trial to evaluate the efficacy and safety profile of miLOOP-assisted phacoemulsification compared with standard phacoemulsification in patients with advanced visually significant cataracts. The trial focuses on objective intraoperative parameters, corneal endothelial outcomes, postoperative visual outcomes, and the incidence of intraoperative and postoperative adverse events.

Eligible participants are randomized in a 1:1 ratio to undergo either standard phacoemulsification using conventional nuclear disassembly techniques or miLOOP-assisted lens fragmentation followed by standard phacoemulsification. Randomization is performed using block randomization to ensure balanced allocation between treatment groups. Participants are masked to treatment allocation, whereas the operating surgeon is not masked due to the nature of the intervention.

To minimize variability related to surgical technique, all procedures are performed by a single experienced cataract surgeon using a standardized phacoemulsification platform with predefined ultrasound and fluidics parameters applied uniformly across all cases. In the standard phacoemulsification group, nuclear disassembly is primarily performed using the stop-and-chop technique, with alternative disassembly techniques employed only when clinically indicated. In the miLOOP-assisted group, lens fragmentation is performed following capsulorhexis and hydrodissection, with sequential loop constrictions used to divide the nucleus into quadrants prior to phacoemulsification and aspiration.

Intraoperative parameters, including cumulative dissipated energy, total ultrasound time, total case time, and estimated fluid usage, are recorded directly from the phacoemulsification system. Intraoperative complications are documented prospectively for all cases.

Postoperative management, including topical medication regimens and follow-up schedules, is standardized across both treatment groups. Participants undergo postoperative assessments at predefined intervals, during which comprehensive ophthalmic examinations are performed. Corneal status is evaluated clinically and objectively using non-contact specular microscopy. Measurements of corneal endothelial cell density, corneal thickness, and endothelial morphometric parameters are obtained preoperatively and at designated postoperative time points by trained personnel masked to treatment allocation.

The primary objective of this study is to compare corneal endothelial cell loss between miLOOP-assisted phacoemulsification and standard phacoemulsification in eyes with dense cataracts. Secondary objectives include comparison of intraoperative energy utilization, postoperative visual outcomes, corneal edema, and the incidence of intraoperative and postoperative adverse events.

This study is conducted in accordance with the principles of Good Clinical Practice and the Declaration of Helsinki following approval from the appropriate institutional ethics committee. Data are collected using standardized case report forms and analyzed using appropriate statistical methods to compare outcomes between the two treatment groups.

The results of this trial are intended to provide prospective randomized evidence regarding the role of miLOOP-assisted phacoemulsification in reducing ultrasound energy requirements and preserving corneal endothelial integrity in the surgical management of dense cataracts.