Treatment of High Astigmatism with WaveLight Allegretto Eye-Q Excimer Laser Platform

INTRODUCTION: The WaveLight Allegretto Eye-Q is a flying-spot excimer laser, with a pulse repetition rate of 400Hz, with two galvanometric scanners for positioning laser pulses. The system has an infrared high speed camera operating at 400Hz to track the patient’s eye movements that either compensates for changes in eye position or interrupts the treatment if the eye moves outside a preset predetermined range. AIM: The purpose of this study was to investigate WaveLight Allegretto Eye-Q 400Hz laser delivery platform aimed to correct astigmatism by subjecting the pre and postoperative astigmatic values to vector analysis. METHODS: Patients were divided into two groups, depending on the type of astigmatism. Astigmatism was between 2 and 7 diopters (D). A total of 188 eyes (110 patients), 127 eyes (71 patients) with myopic astigmatism and 61 eyes (39 patients) with mixed astigmatism underwent unremarkable LASIK correction on WaveLight Allegretto Eye-Q 400Hz. The preoperative and postoperative sphere, negative cylinder [C] and axis (ø) of manifest refractions were subjected to vector analysis by calculations of the standard J(0) (cos [4π(ø-90)/360]xC/2) and J(45) (sin[4π(ø-90)/ 360]xC/2). RESULTS: Reporting the key results, we found that J(0) significantly reduced after LASIK (p<0.001) but not J(45). There was no significant association between individual pairs of pre and postoperative J(0) &J(45 )values. CONCLUSION: WaveLight Allegretto 400Hz showed excellent results for treating patients with high astigmatism, regardless whether it is mixed or myopic astigmatism. The J(45) did not reduce significantly possibly because of the low number of eyes with oblique astigmatism. There was no genuine difference postoperatively between groups treated on WaveLight Allegretto platform according to the vector analyses.