Corneal Epithelial Thickness Alterations in Multiple Myeloma Patients Treated with Belantamab Mafodotin.

To quantify sectoral corneal epithelial thickness (CET) changes in patients with multiple myeloma treated with belantamab mafodotin using anterior segment optical coherence tomography (AS-OCT), and compare CET measurements with those of normal eyes. This retrospective observational study analyzed eight eyes from four patients with multiple myeloma who received belantamab mafodotin and subsequently discontinued therapy because of keratopathy. Clinical parameters-including best-corrected visual acuity (BCVA), mean keratometry, spherical equivalent, and Keratopathy Visual Acuity (KVA) scale-were assessed at baseline and at treatment discontinuation. CET at discontinuation was measured with using swept-source AS-OCT with a 25-sector mapping protocol: a central zone (0-2 mm) and three concentric annuli-inner (2-5 mm), middle (5-7 mm), and outer (7-10 mm)-each subdivided into eight sectors (S, SN, N, IN, I, IT, T, ST). CET values from the patient group were compared with those from 14 normal eyes of 11 controls. Therapy was discontinued after a mean of 5.5 cycles, approximately 4 months after the first infusion. From baseline to discontinuation, BCVA worsened from logMAR 0.04 to 0.20 (p = .027), and the KVA scale increased from 0.25 to 2.88 (p = .008). Compared with normal eyes, eyes exposed to belantamab mafodotin exhibited significantly thinner epithelium across all 25 sectors-including the central and all annular sectors (all p < .05). Within-patient sectoral analysis revealed greater thinning in the inferior than in the superior sectors of the middle ring (5-7 mm; p = .039). No significant nasal-temporal asymmetry was observed. Patients who discontinued belantamab mafodotin therapy due to keratopathy exhibited diffuse epithelial thinning relative to normal eyes, with disproportionate thinning in inferior mid-peripheral sectors. Sectoral AS-OCT mapping of the corneal epithelium may serve as an objective biomarker for quantifying belantamab mafodotin-associated ocular surface toxicity.