Preoperative cataract grading by Scheimpflug imaging and effect on operative fluidics and phacoemulsification energy
Received 22 February 2009; received in revised form 26 August 2009; accepted 27 August 2009.
Purpose
To evaluate the power use, chamber stability, and surgical efficiency of a phacoemulsification system when cataracts were graded preoperatively using the Pentacam Nucleus Grading System (PNS) and adjustments were made in phaco parameters based on the cataract grade.
Setting
Royal Victoria Hospital, Barrie, Ontario, Canada.
Methods
Cataracts were graded using Scheimpflug imaging (Pentacam) in consecutive patients. In Group 1, surgery was performed with no change in parameters. In Group 2, adjustments were made preoperatively in fluidics and phaco power to reflect the cataract grade determined by Scheimpflug imaging. Parameters assessed in both groups included effective phaco time (EPT), balanced salt solution (BSS) use, and needle time to remove the cataract.
Results
There were 200 patients in each group. Emulsification and aspiration of higher and lower grades of cataract took statistically significantly less EPT and BSS in Group 2 (preoperative parameter adjustments) than in Group 1. The needle time for the higher grades of cataract was statistically significantly less in Group 2. For cataracts of a middle grade (2 to 3; 63% of cases), there was no statistically significant difference between standard phaco settings and adjusted settings. The cataract was effectively aspirated in both groups.
Conclusion
Preoperatively adjusting phaco parameters based on cataract grade helped improve overall efficiency by reducing the amount of energy and fluid used in the eye and reducing overall phaco time.
Financial Disclosure
The author has no financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.
From a private practice, Barrie, Ontario, Canada
Corresponding author: Donald Nixon, MD, Trimed Eye Center, 190 Cundles Road, East Suite 100c, Barrie, Ontario L4M 4S5, Canada.
Additional financial disclosure: Dr. Nixon is the inventor of the Pentacam Nucleus Grading System; pending patent is held by Oculus. Dr. Nixon is a consultant to Oculus, Abbott Medical Optics, Inc., Allergan, Inc., and Novartis Corp.
ABSTRACT