Vector Analysis of High-Astigmatism Correction in Small Incision Lenticule Extraction: A Comparative Study of VisuMax...

Area of Science:

• Ophthalmology
• Refractive Surgery
• Laser Technology

Background:

• Small Incision Lenticule Extraction (SMILE) is effective for myopia, but astigmatism correction can be undercorrected.
• The VisuMax 800 femtosecond laser was developed to improve SMILE's astigmatic correction capabilities.
• Key advancements include centration assistance, automated cyclotorsion adjustment, and increased laser speed.

Purpose of the Study:

• To compare the astigmatic correction outcomes of SMILE using VisuMax 500 versus VisuMax 800.
• To evaluate the efficacy of the VisuMax 800 in correcting high astigmatism.

Main Methods:

• Retrospective comparative study of 155 eyes with preoperative astigmatism ≥ 3.0 diopters.
• 91 eyes treated with VisuMax 500, 64 eyes with VisuMax 800.
• Vector analysis using the Alpins method at 3 months postoperatively.

Main Results:

• VisuMax 800 group showed significantly lower residual astigmatism (-0.52 D vs. -0.63 D).
• Superior vector analysis outcomes for VisuMax 800: improved surgically induced astigmatism, correction index, flattening effect, and index of success.
• Statistically significant improvements (P < 0.05) across multiple vector parameters favoring VisuMax 800.

Conclusions:

• VisuMax 800 provides superior astigmatic correction in SMILE for highly astigmatic eyes.
• Lower residual astigmatism and enhanced vector parameters demonstrate improved refractive accuracy.
• Integrated features of VisuMax 800 contribute to better surgical outcomes in astigmatism correction.