Structural Normalization Of Corneal Astigmatism In Smile Pro — Bidirectional Case Analysis With Vector And Ray-Tracing Correlation

To evaluate the clinical impact of Topography-Modified Refraction (TMR), derived from Scheimpflug total corneal imaging and ray-tracing analysis, in 50 consecutive SMILE Pro procedures and to assess refractive accuracy, visual acuity outcomes, and postoperative higher-order aberration (HOA) behavior

Laservision Ambulatory Surgical Unit, Athens, Greece and the NYU Grossman School of Medicine, Department of Ophthalmology, New York City, NY

Preop spherical equivalent was −2.75 D (median ± SD: −2.75 ± 1.10 D).
Cylinder was −1.25 D (median ± SD: −1.25 ± 0.75 D).

TMR was derived from total corneal power distribution (Scheimpflug imaging), central corneal astigmatism, and ray-tracing assessment (including dilated evaluation when indicated). Treatment planning prioritized structural corneal normalization rather than manifest refraction alone.

Cylinder magnitude was increased relative to manifest refraction in 36/50 eyes (72%), reduced in 7/50 eyes (14%), and unchanged in 7/50 eyes (14%).

Postoperative evaluation at 1 and 3 months included UDVA, CDVA, residual cylinder, Alpins vector analysis, Scheimpflug tomography, ray-tracing wavefront analysis, and higher-order aberration profiling.

Preoperative CDVA averaged 20/18; postoperative UDVA improved to 20/14.

One line of vision was gained in 55% of eyes and two lines in 8%.

Ninety-two percent of eyes were within ±0.50 D of intended spherical equivalent, and 96% were within ±0.75 D. Residual refractive cylinder was ≤0.50 D in the majority of cases. Vector analysis demonstrated reduced predicted residual astigmatism compared with theoretical manifest-based planning, with lower difference vectors and improved target-induced astigmatism alignment.

Three-month ray-tracing analysis showed minimal overall HOA induction; however, a mild but consistent increase in vertical coma (Zernike C7) was observed, correlating with centration/cyclorotation variability during SMILE Pro docking.

SMILE Pro with TMR enhances refractive accuracy and visual function in consecutive cases.
Bidirectional cylinder modulation confirms that TMR functions as a structural normalization strategy rather than a magnitude bias. TMR represents a preoperative structural planning approach distinct from vector-based outcome analysis.
In contrast to contemporary excimer platforms—where active eye tracking and visual-axis–centered ablation have matured—SMILE technology has yet to establish consistent treatment accuracy relative to the visual axis. The observed postoperative C7 increase suggests centration remains a limiting factor in lenticule extraction. Centration/cyclorotation and integration of HOA customization may further optimize visual outcomes.