Subjective intermittent colour vision loss as the initial presentation of chronic myeloid leukemia

To report a case of subjective intermittent loss of bilateral colour vision and episodic white-out vision in a patient with undiagnosed chronic myeloid leukemia (CML).

A patient initially diagnosed with diabetic retinopathy presented with a chief complaint of subjective intermittent loss of colour vision in both eyes, as well as intermittent bilateral white-out vision. These symptoms previously went uninvestigated until a thorough history revealed concurrent constitutional symptoms including recent night sweats and fevers. Closer fundus examination revealed that the lesions previously thought to be diabetic retinal hemorrhages were Roth spots.

An unusual chief complaint of colour vision loss and multiple Roth spots in the context of chronic night sweats and fevers prompted further workup. A CBC with differential revealed a markedly increased WBC count and the patient was diagnosed with CML. Cytoreduction therapy led to complete resolution of the patient's visual symptoms and a return to normal WBC count at the most recent follow up appointment. We report, to our knowledge, the only case of colour vision loss as the initial presenting symptom of CML in the current literature, and reiterate the importance of a thorough history, neuro-ophthalmic examination and relevant investigations in patients with unusual visual symptoms, including intermittent loss of colour vision. In this case, we speculate that hyperviscosity syndrome secondary to CML was the cause of this patient's peculiar visual disturbance.