J Refract Surg 2012 Mar 21;28(3):215-9. Epub 2011 Nov 21.
Fluminense Federal University, Rio de Janeiro, Brazil.
Purpose: To evaluate central corneal thickness (CCT) and ocular biomechanical properties in patients before and after clear corneal phacoemulsification.
Methods: Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated IOP (IOPg) were measured with the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments) in 36 consecutive patients (47 eyes) who underwent clear corneal phacoemulsification. Central corneal thickness was measured with the Pentacam (Oculus Optikgeräte GmbH). All measurements were performed prior to surgery and at follow-up at 1, 7, and 30 days postoperatively.
Results: Central corneal thickness was higher at 1 and 7 days compared to preoperatively (P<.05) but not at 30 days. Corneal hysteresis was lower at 1 day than preoperatively (P<.05) but not at 7 and 30 days. Corneal resistance factor was lower at 1, 7, and 30 days compared to preoperatively (P<.05). Corneal-compensated IOP was slightly lower at 1, 7, and 30 days compared to preoperatively, but was not statistically significant (P>.05). Goldmann-correlated IOP was statistically significantly lower at 1 and 7 days than preoperatively (P<.05).
Conclusions: Clear corneal phacoemulsification led to a change in ocular biomechanical properties. The increase in CCT after phacoemulsification was followed by a reduction in CRF and CH. Mean IOPcc was similar before and after phacoemulsification, indicating that IOPcc may be a more accurate indicator of true IOP than IOPg.