Hyaluronic Acid vs Poly- L- Lactic Acid for the Treatment of Upper-Eyelid Hollowing: A Prospective Cohort Study

Abstract Background Upper-eyelid hollowing can be treated with hyaluronic acid (HA) or poly-L-lactic acid (PLLA), which differ in onset and durability; objective comparative data are limited. Objectives The aim of this study was to compare 9-month efficacy and safety of HA vs PLLA based on objective image-based metrics and patient-reported outcomes. Methods This single-center, prospective, nonrandomized cohort study enrolled patients who chose HA (single session) or PLLA (three sessions, 4 weeks apart) after standardized counseling.Three co-primary image-derived metrics—hollow area, mean curvature of the superior sulcus, and arc/chord ratio—were assessed at baseline and at 3, 6, and 9 months after the last treatment (T1-T3). Linear mixed-effects models estimated between-group differences(fixed: group, time, group × time, random: participantwith eye nested), with Holm adjustment for family-wise error.FACE-Q and Upper-Eyelid Hollowing Severity Scale (UEHSS) were secondary endpoints and safety used the full sample. Results Thirty-six participants (72 eyes) were enrolled, and 66 eyes completed follow-up. In the matched cohort (n = 48 eyes), at T1, HA outperformed PLLA across all co-primary metrics (Holm-adjusted P < .001). At T2, HA remained superior for hollow area and mean curvature (P < .01) with no difference in arc/chord ratio. By T3, PLLA showed greater improvement in all 3 metrics (P < .001). FACE-Q scores at T3 were comparable, whereas UEHSS slightly favored HA (odds ratio, 1.45; 95% CI, 1.02-2.06). Transient swelling and tenderness were more frequent with PLLA, whereas small lumps occurred only with HA, and no severe adverse events were observed. Conclusions HA provides greater early improvement, whereas PLLA yields superior outcomes by 9 months, supporting pathway-based treatment selection. Level of Evidence: 3 (Therapeutic)