Evaluation of visual evoked potential in chronic myeloid leukemias

Visual complaint is not very uncommon in chronic myeloid leukemia (CML) patients. Our study aims to evaluate the visual pathway using visual evoked potential (VEP) in cases of CML at the time of diagnosis and 6 weeks after tyrosine kinase therapy, to find out treatment impact in asymptomatic as well as symptomatic individuals and compare it with the general population.

This is an analytical cross-sectional study. The study group comprised 20 newly diagnosed cases of CML and 20 age- and sex-matched healthy control population. A thorough history and clinical examination with detailed ophthalmological studies, including VEP, were done. Cases who had VEP abnormalities were then followed-up after 6 weeks post-Imatinib therapy and underwent repeat investigations, including VEP.

VEP in cases was significantly deranged (P < 0.001), where 15 patients (75%) had abnormalities in VEP compared to 3 (15%) in control. Post 6 weeks chemotherapy, Out of 10 cases that were followed up, 7 patients had achieved hematological remission with normal VEP finding (P = 0.02). Simultaneously, an increase in hemoglobin (P = 0.002) and reduction in total leukocyte count (TLC) (P = 0.004) were observed.

Considerable evidence appear to support the notion that CML patients have a higher prevalence of ophthalmic manifestations as compared to the general population, which can be screened earlier with objective tests like VEP. Concurrently, hematological parameters and VEP showed derangement at the time of diagnosis. After 6 weeks of Imatinib treatment, the improvement in VEP can then be attributed to a reduction in TLC. Hence it can be deduced that VEP has paramount importance in the early identification of ophthalmic manifestations, which are reversible with timely treatment.