Purpose

To test whether a previously developed software based on Bézier and spline curves can quantitatively describe surgical changes in the upper eyelid contour beyond height — also capturing contour shape and symmetry — in ptosis surgery with or without upper blepharoplasty.

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Methods

Retrospective analysis of 22 eyelids from 12 patients undergoing reinsertion of the levator palpebrae superioris aponeurosis. Pre- and postoperative photographs (median follow-up 126 days) were analysed using the software. Three parameter families were assessed: height (margin reflex distance and radial/vertical MLPD); shape (curvature κ_max and κ_mean; Procrustes fluctuating component vs normative reference; composite Shape and Global Normality indices); symmetry (Asymmetry Grade, composite Symmetry Index, bilateral Fréchet distance). Wilcoxon signed-rank test was applied.

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Results

Significant elevation was achieved (Δmargin reflex distance +0.58 mm, 95% CI +0.34 to +0.82; p=0.0005). No surgical peaking was introduced: measured with κ_max, this parameter stayed within the normative range with no eye exceeding the threshold, and pre-existing peaks were corrected in selected cases. Procrustes fluctuating component did not worsen (Δ +0.023 mm; p=0.24); Shape Index did not deteriorate (Δ +0.07; p=0.09). Global Normality Index improved significantly (Δ +0.11; p=0.0015), driven by elevation. Symmetry response was heterogeneous, with no significant group change (ΔSymmetry Index −0.04; p=0.30).

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Conclusion

Eyelid height is relevant but no longer sufficient as a ptosis outcome. Objective parameters describing contour shape and interocular symmetry are needed for comprehensive reporting. The software delivers such parameters and proves sensitive to surgical change. Systematic quantitative descriptors will be key to incorporating artificial intelligence into oculoplastic surgery.

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Additional Authors

First name	Last name	Base Hospital / Institution
Beatriz	Ventas Ayala	Hospital Ramon y Cajal
Constanza	Barrancos Julian	Hospital Ramon y Cajal
Marco	Sales Sanz	Hospital Ramon y Cajal

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