Purpose:
To evaluate the central corneal thickness (CCT) and corneal biomechanical properties - hysteresis and corneal resistance factor in patients prior to and following phacoemulsification with intraocular lens implantation.
Methods:
This is a retrospective study. Thirty six consecutive patients (47 eyes) that underwent phacoemulsification surgery and intraocular lens implantation were enrolled. Full ophthalmologic clinical assessment including CCT (Pentacam, Oculus, Wetzlar, Germany) and ocular response analyzer (ORA, Reichert Ophthalmic Instruments, Buffalo, NY, USA) measurements were performed in all cases prior to surgery (Pre) and at follow-up time points: day 1 (D1), day 7 (D7) and day 30 (D30). The ORA parameters were: hysteresis, corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg). Exclusion criteria were corneal diseases or scars, intra-ocular pressure greater than 23.5 mmHg in all measurements and previous ocular surgery. The Kolmogorov-Smirnov test was used to check for a normal distribution. Differences between the measurements obtained using the two instruments were evaluated using the Student's paired t-test. Statistical package for social sciences (SPSS 12.0 software for Windows, SPSS Inc., Chicago, IL) was used for statistical analysis.
Results:
Mean and standard-deviation of ORA parameters and CCT are shown in Table 1. There is no difference between the mean values of CCT Pre and D30 (p>0.05) and hysteresis Pre and D30 (p>0.05). The difference between mean values of CRF Pre and D30 was statistically significant (p<0.05).
Conclusions:
The increase of CCT after phacoemulsification is followed by a reduction in the CRF. Even when CCT returns to preoperative values, the CRF remains reduced in short-term postoperative period.
Keywords: cornea: clinical science