Abstract
PurposeTo compare functional outcomes of Wavelight Allegretto Eye-Q 400Hz and Schwind Amaris 750S excimer laser for astigmatism between 2 and 7 diopters(D).MethodsProspective comparative non-randomized case series of 480 eyes assigned in two laser groups and further divided into myopic and mixed astigmatism subgroups. All treatments were centered on corneal vertex. One-year results were compared between the groups. Statistical analysis was performed using z-test.ResultsBoth Allegretto and Amaris postoperative uncorrected distance visual acuity (UDVA) improved in comparison to preoperative corrected distance visual acuity (CDVA). The difference was significant in the Allegretto group for myopic astigmatism (p = 0.017). There was no difference in postoperative UDVA between lasers. Average sphere decreased in all groups for both lasers (p < 0.001) without difference in effectiveness of spherical correction between lasers for both groups. In Allegretto, average cylinder decreased from −3.30D to −0.55D in myopic astigmatism (p < 0.001) and from −3.84D to −0.85D in mixed astigmatism (p < 0.001). In Amaris average cylinder decreased from −3.21D to −0.43D in myopic astigmatism (p < 0.001) and from −3.66D to −0.58D in mixed astigmatism (p < 0.001). Amaris group had less residual astigmatism (myopic astigmatism p = 0.023, mixed astigmatism p < 0.001). Mean spherical aberration shifted from positive to negative in mixed astigmatism for both lasers.ConclusionBoth lasers are effective in terms of UDVA, CDVA, spherical correction, and preservation of high-order aberrations. However, Amaris was more effective in cylinder correction.
Highlights
LASER in-situ keratomileusis (LASIK) is a highly successful keratorefractive procedure for the treatment of myopia and low degrees of hyperopia
Mean spherical aberration shifted from positive to negative in mixed astigmatism for both lasers. Both lasers are effective in terms of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical correction, and preservation of high-order aberrations
The treated eyes were further subdivided according to the type of astigmatism, myopic astigmatism, or mixed astigmatism
Summary
LASER in-situ keratomileusis (LASIK) is a highly successful keratorefractive procedure for the treatment of myopia and low degrees of hyperopia. Treatment of astigmatism, especially hyperopic astigmatism, is still a therapeutic challenge, and often results in significant refractive misscorrections [1, 2]. Recent advances in excimer laser technology, such as the use of aspheric ablation profiles, incorporation of higher-order aberration treatment, and eye trackers, have presumably led to better refractive outcomes and reduced induction of higher-order aberrations postoperatively [3, 4]. 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 beam is a small-spot,
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