Short- and Long-Term Effect of Ultrasound Energy on Changes in IOP After Cataract Surgery by Phacoemulsification
Purpose
To investigate the association between ultrasound energy, expressed as cumulative dissipated energy, and changes in intraocular pressure following uncomplicated cataract surgery by phacoemulsification.
Methods
In this prospective study, nonglaucomatous subjects underwent cataract surgery by phacoemulsification. Intraocular pressure was compared by clustered linear regression at four separate time points: preoperative, 1 day, 1 month, and 3 months after cataract surgery. Changes in intraocular pressure at 1 day, 1 month, and 3 months were evaluated as a function of cumulative dissipated energy using univariate and multivariate clustered linear regression models to determine the association between ultrasound energy and postoperative changes in intraocular pressure. The multivariate clustered linear regression model adjusted for sex, ethnicity, age, axial length, spherical equivalent, mean preoperative Shaffer gonioscopy grade of all four quadrants, cataract grade, central corneal thickness, and use of both eyes in the same subject.
Results
One hundred and sixty-one eyes from 116 patients were analyzed. Prior to cataract surgery, average intraocular pressure was 14.5±15.2 mmHg. Postoperative intraocular pressure significantly increased to 16.0±4.9 mmHg at 1 day (P=0.037) and decreased to 12.4±3.1 and 12.3±3.0 mmHg at 1 and 3 months, respectively (both P<0.0001). Intraocular pressure changes at 1 day, 1 month, and 3 months did not demonstrate significant associations with cumulative dissipated energy measurements in either univariate or multivariate clustered linear regression analyses (all P>0.05).
Conclusion
The amount of ultrasound energy delivered to the eye during phacoemulsification, expressed as cumulative dissipated energy, was not associated with short and long term postoperative changes in intraocular pressure.