Fluidics Stability And Endothelial Safety Across Surgical Experience Levels: A Standardized Evaluation Of The Rayner Sophi™ Phacoemulsification System (Rayner, Working Uk): A Pilot Comparative Study Of Consultant And Resident Cases

To eveluate endothelial safety and fluidics stability during standardized phacoemulsification performed with the Rayner Sophi™ Phacoemulsification System, comparing outcomes between consultant and supervised resident surgeons. The study aimed to determine whether cumulative dissipated energy and effective phaco time differences associated with surgical experience translate into measurable differences in endothelial cell loss and postoperative corneal thickness changes under controlled parameters. 

The setting is at the Eye and Vision Institute at The Medical City in Pasig City, Philippines. All surgeries were performed in a tertiary referral ophthalmic center using a unfirom operating environment, standardized instrumentation, and identical phacoemulsification parameters across cases. 

This prospective pilot study included 20 eyes undergoing uncomplicated cataract surgery (consultant n=10;resident n=10). Only LOCS III Grade 2-3 nuclei were included to minimize variability in lens density. Uniform surgical protocol was applied, including identical incision size, phacoemulsification parameters, fluidics settings, viscoelastic use, and nucleus disassembly technique. Endothelial cell density (ECD, cells/mm²) was measured via specular microscopy and central corneal thickness (CCT, µm) via pachymetry preoperatively and at Day 1, Week 1, Month 1. Primary outcomes were percentage endothelial cell loss (ECL), and change in CCT (ΔCCT). Secondary measures included cumulative dissipated energy and effective phacoemulsification time. 

Baseline ECD and CCT were comparable between groups (p>0.05). At 1 month, mean ECL was 6.8±2.4% in consultant cases and 7.5±2.9% in resident cases (p=0.62). Day 1 CCT increased transiently in both groups (+34±12 µm vs +38±15 µm, p=0.54) with progressive normalization by week 1 and near baseline values at Month 1. Although resident cases demonstrated modestly higher CDE and longer effective phaco time, these differences did not result in significantly greater endothelial compromise. No intraoperative complications or persistent postoperative corneal edema were observed. 

Under standardized surgical conditions and controlled nuclear density, phacomeulsification using the Rayner Sophi™ system demonstrated low endothelial cell loss and predictable pachymetric recovery in both consultant and resident cases. Despite slightly higher energy utilization among residents, corneal safety outcomes were comparable, suggesting stable fluidics and efficient energy modulation in training enviornments. Larger, adequately powered studies are warranted to validate these preliminary observations.