Tamoxifen (Selective Estrogen Receptor Modulator) Induces Major Topographical Changes Mimicking Ectasia In A Post-Lasik Patient

Ectasia after LASIK represents a rare yet major complication in refractive surgery. It typically occurs either due to excessive ablation, or a combination of preexisting biomechanical instability with secondary factors exacerbating the vulnerable postoperative steady state.  

Hormones such as estrogen can profoundly influence corneal biomechanics, and may trigger late-onset ectasia, even years after LASIK. Certain medications modulate tissue estrogen sensitivity and may potentially induce corneal remodeling.

Here, we present a case with a history of LASIK and a decade of stable vision, who experienced fluctuating topographical changes following breast cancer treatment with the selective estrogen receptor modulator (SERM), tamoxifen.

ELZA Institute, Dietikon, Switzerland and Pallas Kliniken, Olten, Switzerland.

A 36-year-old female patient was evaluated in May 2021 due to rapidly deteriorating vision in her left eye. She had undergone LASIK surgery in 2011, and pre-LASIK tomographies displayed regular surface shape in the right eye and minimal surface shape asymmetry in the left eye. Anterior surface asymmetry is a well-established indicator of ectasia, even in the absence of Belin-Ambrosio enhanced display changes. Following LASIK, the patient achieved spectacle independence, and her unaided vision remained stable for a decade. Six months prior to presentation, she was diagnosed with breast cancer and initiated tamoxifen therapy A few weeks after initiation of therapy, her left VA started decreasing.

Upon examination, her left CDVA was 20/20, with a subjective refraction of +0.50 -3.50 × 005. Her right eye CDVA was also 20/20 with +0.50 -3.50 × 005. Slit-lamp examination revealed no abnormalities. Anterior segment OCT coupled with corneal topography confirmed post-LASIK ectasia in the left eye. Corneal cross-linking (CXL) was considered if progression occurred between presentations and follow-up visits. After consultation with her oncologist, the tamoxifen therapy for hormone-dependent breast cancer remained unchanged.

At 3 and 6 months following the initial visit, the patient's left eye CDVA was 20/25. Corneal tomography revealed a marked reduction in corneal curvature asymmetry compared to the initial evaluation.

This case presents the initial evidence indicating that tamoxifen treatment for breast cancer could precipitate significant post-LASIK topographical alterations, implying a potential influence of Selective Estrogen Receptor Modulators (SERMs) on corneal morphology through estrogen receptor inhibition or partial antagonism. SERM administration might introduce an overlooked risk element for undesired alterations in corneal shape, especially noteworthy in individuals with pre-existing corneal biomechanical instability or during the evaluation of refractive surgery candidacy.