Abstract
Purpose: :
Investigate the association between corneal biomechanical parameters and phacoemulsification with intraocular lens implantation in glaucoma patients using the Ocular Response Analyzer (ORA).
Methods: :
One hundred and thirty one eyes of 85 glaucoma patients were divided into two groups: phakic (76) vs. pseudophakic (55) eyes. The patients underwent measurement of corneal hysteresis (CH), corneal resistance factor (CRF), and cornea-compensated intraocular pressure (IOPcc) via the ORA. One glaucoma specialist reviewed the clinical chart to determine the cup-to-disk ratio (CDR), intraocular pressure (IOP) by Goldmann applanation tonometry, central corneal thickness (CCT) by an ultrasonic pachymeter and glaucoma severity classification by Humphrey 24-2 visual field (HVF) analysis. Exclusion criteria were intraocular surgery other than cataract surgery, complications during cataract surgery, less than one year out from cataract surgery, and less than 6 months out from laser trabeculoplasty.
Results: :
In both groups, a lower CH was associated with a higher IOP (p=0.007), a higher IOPcc (p=0.0001), a lower CCT (p=0.001), an older age (p=0.001) and more severe HVF defects, however this association did not reach statistical significance (p=0.08). The pseudophakic group was on overage older age than the phakic group (77.7±8.61 vs. 65.2±12.5 years, p<0.001). The statistical analysis was done controlling for this difference by linear mixed effects regression.The CRF (9.31±13.7 vs. 8.57±11.5, p=0.15), IOP (14.2±3.68 mmHg vs. 15.1±3.59 mmHg, p=0.19) and IOPcc (17.2±4.47 vs. 17.1±3.91mmHg, p=0.36) were similar between pseudophakic and phakic groups respectively. The CCT, CDR and severity of HVF classification were similar between both groups (p>0.05) as well. However, CH was significantly lower in the pseudophakic than in the phakic group (8.59±1.40 mmHg vs. 9.12 ± 1.59 mmHg, p=0.04).
Conclusions: :
Despite adjusting for age and having similar CCT, CDR, severity of HVF classification, CRF, IOP and IOPcc, the pseudophakic group had a lower CH compared to the phakic group (8.59±1.40 mmHg vs. 9.12±1.59 mmHg, p=0.04). These findings suggest an independent correlation that may be related to a change in corneal biomechanics after phacoemulsification and intraocular lens implantation in patients with glaucoma.
Keywords: treatment outcomes of cataract surgery • differentiation • reading