Abstract
Purpose: :
To demonstrate the pattern of cavitation for a 21 gauge (g) straight phaco tip (ST) and a 21g bent tip (BT) and correlate these patterns with clinical performance.
Methods: :
High-speed video photography was carried out with a 21g ST and a BT tip on the WHITESTAR Signature® ELLIPS® FX handle in vitro to demonstrate the tip displacement and patterns of cavitation for each configuration. Comparative phaco parameters were then assessed during micro-implantation cataract surgery using the WHITESTAR Signature® system with the ELLIPS® FX handpiece using a 21g ST or BT tip at a setting of 10-25% power with 100 cases in each group. Phaco technique (horizontal chop), settings, bottle height, vacuum, and pump ramp were the same throughout. Measures include total ultrasound energy (FX), balanced salt solution (BSS) used for irrigation, and total phaco time with the results for the two tip designs compared.
Results: :
High-speed video shows cavitation bubbles traveling in a relatively straight line from the ST, while the BT produced a more complex pattern. A total of 101 ST and 22 BT phaco cases have been completed thus far. Phaco power parameters had to be lowered to 5-15% for the BT cases due to excessive power dispersion in the eye. Mean FX, BSS use, and phaco time were consistently lower for the BT compared to the ST cases. For grade 1 cataracts, mean ST FX was 24.1 (n=15) compared to 8.5 for the BT (n=4). BSS used was 23.7 ml and 17.5 ml for ST and BT cases while phaco time was 18.2 sec and 9.45 sec, respectively. For grade 5 cataracts, mean ST FX was 151 (n=5) compared to 86 for the BT (n=3). BSS used was 99 ml and 68.3 ml, while phaco time was 138.2 sec and 101.1 sec for the ST and BT cases, respectively.
Conclusions: :
The 21g ST and BT tips performed differently during the micro-implantation cataract surgery using the WHITESTAR Signature® system with the ELLIPS® FX handpiece. Although both tip designs performed well to date, surgeries with the BT used less total ultrasound energy, BSS, and phaco time.