TOPOGRAPHICAL AND FUNCTIONAL ANALYSIS OF DIFFERENT SURGICAL STRATEGIES FOR ADVANCED PELLUCID MARGINAL DEGENERATION: A LONG TERM FOLLOW-UP

To compare clinical and topographical outcomes of three different surgical strategies for advanced pellucid marginal degeneration (PMD).

Retrospective, interventional, monocentric case series.

Retrospective, interventional case series of 8 advanced PMDs undergoing three different      surgical interventions: Sliding Keratoplasty (SK), Sliding Keratoplasty with Relaxing Incision (SKRI), Sector Lamellar Keratoplasty (SLK). Pre-operatively and at 1, 3, 6, 12-month and final follow-up (mean 50.8 months) post-operatively, we collected: uncorrected  and corrected distance visual acuity (UDVA and CDVA), spherical equivalent (SE), refractive astigmatism (RA), corneal Ks, topographical astigmatism (TA) and calculated against-the-rule (ATR) component.

CDVA significantly improved from 6 months after surgery: six eyes (75%) had a CDVA≥20/40 at the end of the study. TA was intentionally overcorrected toward with-the-rule astigmatism at 1-month, and then decreased at 12-month and at final follow-up (p<0.05). One-month ATR-component significantly decreased from baseline (1.9±1.1 vs. 17.6±6.3 D pre-operatively, p=0.0015) and resulted quite stable over the study period (4.2±4.2 D at final follow-up). In subgroup analysis, SK and SKRI showed better CDVA and RA at the end of the study, while SLK showed more TA stability. Comparing baseline to the final follow-up, in SK, ATR component decreased from 16.8±8.3 D to 5.9±3.6; in SKRI, from 18.9±3.6 D to 3.3±3.3 D; in SLK group from 17.0±10.3 D to 1.9±1.5 D.

We reported long-term favorable outcomes in the surgical treatment of advanced PMD, with SK and SKRI offering better visual outcomes but being more inclined to astigmatism regression over time, while SLK being more stable but offering worse refractive outcomes.