Abstract
Purpose: :
To examine the effects of cumulative dissipated energy on postoperative corneal pachymetry following uncomplicated cataract surgery in resident performed cases
Methods: :
A retrospective study was conducted on 41 eyes of 39 patients following uncomplicated cataract surgery by one resident surgeon at a single surgical center. All patients underwent identical surgical technique and procedure using the Alcon Infinity system with Ozil and a 2.4mm temporal clear corneal incision. All patients underwent purely torsional ultrasound and final cumulative dissipated energy (CDE) was noted at the end of each case. Preoperative central corneal pachymetry and postoperative measurements were assessed at day 1, week 1 and 1 month. Intraocular pressure measurements were also made during each time interval
Results: :
Patients were stratified into two groups based on cumulative dissipated energy (CDE). Group 1, n=24 had CDE of less than 20. Group 2, n=17 had CDE greater than 20. There was no statistical significance in the difference between age, preoperative intraocular pressure or postoperative intraocular pressure in either group. Mean preoperative pachymetry in group 1 was 547.16µm, and 544.94µm in group 2. Mean CDE in each group was 14.19 and 26.40 respectively with CDE max of 34.86. Mean postoperative pachymetry at 1 day, 1 week and 1 month was 598.94, 590.11, and 575.43 respectively. Group 2 mean postoperative pachymetry was 588.59, 583.24, and 575.23 respectively
Conclusions: :
It has been well published that extended cumulative dissipated energy can damage corneal endothelial cells leading to prolonged and lasting corneal edema. It is, however, unknown what the upper threshold for cumulative dissipated energy that will cause this long lasting change. This study did not find any statistically significant difference in end central corneal thickness (CCT) despite a range of CDE from 6.35-34.86. In all cases patients returned to baseline CCT by 1 week and maintained level at 1 month. It is believed that technique of torsional ultrasound combined with dispersive viscoelastic to coat the endothelium provides sufficient protection during phacoemulsification in resident performed cases
Keywords: cataract • edema