The Age-Depth Interaction In Lenticule Extraction: A Prospective Paired-Eye Analysis Of Interface Scattering And Micro-Aberrations
Published 2026 - 44th Congress of the ESCRS
Reference: POREF081 | Type: Free paper | DOI: 10.82333/m13e-kk93
Authors: Dr Victor Derhartunian* 1 , Mr Daniel Gruendel 2 , Dr Anna Dabrowska 3 , Mr Samuel Arba Mosquera 4
1EyeLaser Clinic,Vienna,Austria;SwissLaser Clinics,Warsaw,Poland, 2EyeLaser Clinic,Vienna,Poland, 3SwissLaser Clinics,Warsaw,Poland;Military Institute of Aviation Medicine,Warsaw,Poland, 4Schwind Eye Tech Solution,Kleinostheim,Germany
Purpose
To investigate the impact of interface depth (cap thickness) on the Micro Aberration Scattering Index (MASI) following lenticule extraction and to determine if patient age or treatment volume (lenticule thickness) modulates this relationship.
Setting
Specialized Refractive Surgery Center, Clinical Data Analysis Unit.
Methods
This prospective, randomized, paired-eye study evaluated 26 eyes of 13 patients (mean age 31.7 ± 8.0 years). To control for inter-subject biological variance, a contralateral eye design was employed: one eye was assigned to a 110 µm cap and the fellow eye to a 140 µm cap. High-resolution interface quality was quantified on postoperative Day 1 using the MASI index. Multivariate analysis was performed to identify correlations between interface scattering and age, maximal treatment depth (lenticule thickness), and early functional outcomes (UCVA).
Results
A significant depth-dependency was observed in interface quality. The 140 µm cap group exhibited a substantially higher mean induction of scattering compared to the 110 µm group (MASI 19.2 ± 18.3 vs 7.3 ± 13.9). Paired analysis revealed a mean increase in MASI of 40.3% at the deeper interface level. Crucially, the "depth-penalty" for scattering was strongly moderated by patient age (r = 0.645, p = 0.023), whereas total lenticule thickness (treatment volume) showed no independent correlation with scattering (r = -0.07). Day 1 UCVA did not significantly correlate with MASI (r = -0.26), suggesting that while deeper interfaces induce greater micro-scattering, they remain below the threshold for early visual degradation in most subjects.
Conclusions
Interface scattering in lenticule extraction is primarily driven by the depth of the interface rather than the volume of the lenticule. This effect is age-dependent, suggesting that deeper stromal lamellae in older eyes may be more susceptible to laser-induced micro-morphological changes. While deeper caps are often proposed to optimize corneal nerve preservation and ocular surface recovery, surgeons should weigh this against the significant increase in interface scattering. For older patients, a shallower 110 µm cap may be the optimal compromise to maximize interface structural homogeneity.