Residual stromal bed and percent tissue altered for PRK, LASIK and SMILE, side by side, from one refraction.
RSB flag < 300 µm · PTA flag > 40%
How these numbers are calculated
Refraction is converted to minus-cylinder form and vertexed to the corneal plane meridian by meridian. Central depth is driven by the most myopic meridian (sphere + cylinder).
Excimer depth = most myopic meridian × platform µm/D. WaveLight, Schwind and Nidek defaults come from the 2015 Eye and Vision review of 6th-generation excimer platforms (manufacturer-reported). VISX, MEL 90 and Teneo have no published per-diopter figure here and default to Munnerlyn (OZ² ÷ 3). The field is editable so you can match your laser's planning screen.
SMILE lenticule thickness is looked up directly in the Zeiss VisuMax lenticule chart (6.0 mm and 6.5 mm OZ; 7.0 / 7.5 mm cap diameter, 120 µm cap, K 7.7). The chart is indexed by the manifest sphere and minus cylinder, so no vertex conversion is applied. It covers sphere −1.00 to −10.00 D and cylinder 0.00 or −0.75 to −3.00 D. Cylinder of −0.25 or −0.50 D is interpolated between the 0.00 and −0.75 columns and marked as interpolated.
Predicted post-op mean K = pre-op mean K + 0.8 × corneal-plane spherical equivalent (a common rule of thumb; myopic treatments flatten, hyperopic steepen). The factor is editable. Flags default to below 35 D and above 49 D.
Hyperopic and mixed treatments: excimer depth uses the larger of the myopic and hyperopic meridians × µm/D, matching the maximum ablation depth most lasers report. Hyperopic ablation is deepest at the edge of the optical zone, so this is a conservative estimate; confirm it on the laser plan. The Zeiss chart covers myopia only, so SMILE is not calculated for hyperopic spheres.
Planning aid only. Platform factors are approximations; confirm every value against your laser's treatment planning software before surgery.
Surgeon reviewDate
Disclaimer: This calculator is an educational planning aid intended for use by licensed eye care professionals. Its outputs are estimates derived from published formulas, manufacturer-reported data, the Zeiss lenticule chart and user-entered values, and they may not match the treatment plan generated by any specific laser. It is not a substitute for the laser's treatment planning software, a complete preoperative evaluation, or independent clinical judgment. All values must be verified before treatment. Flag thresholds are adjustable defaults, not standards of care, and a result within limits does not establish that a patient is a suitable candidate for surgery. The tool is provided as is, without warranty of any kind, express or implied, including accuracy, completeness, or fitness for a particular purpose. The author and any affiliated organization accept no responsibility or liability for any decision made, or any outcome resulting, from its use. The treating surgeon is solely responsible for all patient selection and treatment decisions.