Abstract
Purpose: :
To evaluate if compensating ocular misalignments during wavefront-guided excimer ablation could improve the postoperative ocular wavefront profile.
Methods: :
Sixty-nine eyes with myopic astigmatism superior to 1D were included. 32 eyes underwent wavefront-guided (WG) excimer ablations (15 LASIK and 17 PRKs) with iris-guided compensation (IGC) for pupil decentration and ocular rotation (VISX Star S4-IR and CustomVue, VISX, USA), and the others underwent WG surgery (18 LASIK and 19 PRKs) without IGC, as controls. Ocular lower- and higher-order wavefront aberrations were measured before and six months after the surgery. Data were computed, rescaled for pupil size, and vectorial analyses were performed to evaluate the surgically-induced changes in main aberrations (astigmatism, coma, and trefoil).
Results: :
Mean intraoperative misalignments were 0.2±0.1 mm for pupil decentration and 3±1.9 degrees for rotation. Residual magnitude of the 2nd-order astigmatism was lower in IGC group (p<0.001), so was the error of treatment axis (p=0.01). Postoperative root mean square of higher-order aberrations was inferior in IGC group (p=0.005) than in controls. Surgically-induced changes in coma and trefoil aberrations have been detailed for magnitude and axis.
Conclusions: :
Compensating ocular misalignments during WG refractive surgery reduces the residual astigmatism, and optimises the treatment of higher-order aberrations in myopic astigmatic patients.
Keywords: refractive surgery • refractive error development • refractive surgery: optical quality