Refractive Instability Associated With Mirvetuximab Soravtansine: Implications For Cataract Surgery

To characterise the refractive and ocular surface changes observed in patients receiving Mirvetuximab soravtansine (MIRV) and to assess the clinical implications for cataract assessment and surgical planning.

Tertiary specialist oncology centre- Royal Marsen Hospital, London, UK.

Retrospective consecutive case series of ten patients undergoing MIRV therapy for folate receptor alpha (FRα)-positive platinum-resistant ovarian cancer, who were referred with new visual symptoms during active treatment. Clinical assessment included best-corrected visual acuity, subjective refraction, slit-lamp microscopy and corneal topography. Findings were compared with documented pre-treatment visual and refractive baselines. Onset and time course of visual symptoms during MIRV treatment cycles, associated refractive change from documented baseline, management strategy, reversibility, and impact on systemic therapy and cataract surgical planning were evaluated.

All patients developed bilateral ocular surface toxicity during MIRV therapy, typically within the early treatment cycles. Slit-lamp examination showed corneal epithelial microcysts with punctate staining. Refractive instability occured relative to baseline, with an initial hyperopic shift and fluctuation of up to 5.00 dioptres over two weeks. Corneal topography demonstrated anterior curvature irregularity without stromal thinning or ectasia. Management was conservative with lubrication and topical corticosteroids. Refractive instability improved over time and no patient required permanent discontinuation of MIRV. Cataract surgery was deferred in several patients due to unstable refraction and ocular surface instability. 

MIRV-associated ocular surface toxicity can induce transient but significant refractive instability secondary to epithelial keratopathy. The refractive shifts observed in this case series are consistent with reversible epithelial disruption rather than permanent stromal structural disease. Conservative management is typically sufficient, allowing continuation of systemic therapy, with only temporary dose modification where required. Fluctuating refraction and ocular surface instability may compromise biometry accuracy and influence surgical timing. Recognition of this treatment-related presentation is essential to avoid diagnostic error, guide operative planning and facilitate counselling regarding the reversibility of these changes.