Vision loss with pembrolizumab treatment: A report of two cases

Vision loss and other ocular toxicities are rare, but detrimental, side effects of immune checkpoint inhibitors. Herein, we report two patients who developed vision loss while on pembrolizumab treatment.

Case 1 - A 58-year-old man was started on pembrolizumab for advanced melanoma. He was tolerating the treatment well. After receiving 14 cycles of pembrolizumab, he developed acute bilateral vision loss and occipital headaches. An emergent ophthalmologic evaluation revealed bilateral shallow choroidal effusion with bilateral focal exudative retinal detachment. After excluding other possible etiologies, inflammatory process secondary to pembrolizumab was suspected. Pembrolizumab was stopped, and the patient was started on a course of systemic and topical steroids. His vision improved within days and he recovered completely within two months. Calculated Naranjo Nomogram score was 7 indicating a "probable" correlation; Case 2 - A 57-year-old man with stage IIIC melanoma was started on adjuvant pembrolizumab. After a few weeks of treatments, he reported minor bilateral vision changes that progressively worsened over a period of six months. An ophthalmologic evaluation revealed bilateral posterior uveitis with right optic disc edema. Pembrolizumab-related inflammatory changes were suspected, and he was started on systemic and topical steroids. His symptoms improved within a few weeks and steroids were tapered. He was re-challenged with pembrolizumab and his symptoms quickly re-occurred. Pembrolizumab was stopped indefinitely and the patient again treated with systemic and topical steroids. His symptoms resolved and his vision returned to baseline within two months. The Naranjo Nomogram score was 9 indicating a "definite" correlation.

Vision loss is a serious complication that may occur at any point during treatment with PD-1 inhibitors. Vision loss is very distressing to the patients and their families. It is prudent for practitioners to recognize early vision abnormalities in patients receiving PD-1 antagonists to prevent permanent vision loss.