Optic nerve infiltration in relapse of acute lymphoblastic leukemia.

Sir,

We read with great interest the article by Bandyopadhyay et al.[1] on unilateral optic nerve infiltration as an initial site of relapse in patients with acute lymphoblastic leukemia (ALL), in remission. The authors have indeed reported a rare and important ophthalmic manifestation. Although periodic ophthalmic examinations are to be conducted in patients with acute leukemia,[23] we do not agree with the authors’ recommendation that for early diagnosis of ALL relapse, a periodic ophthalmic examination is warranted, as it is extremely rare to develop optic nerve infiltration, as admitted by the authors themselves, and this conclusion would be premature based on a single case report.

We also do not agree with the attribution of subnormal vision solely to radiation optic neuropathy. It could be a sequel of the disc edema itself. When commenting on computed tomography (CT) scans in such patients, it is imperative to mention the presence or absence of Central Nervous System (CNS) relapse, radiologically. CT and magnetic resonance imaging (MRI) are more helpful in differentiating optic disc edema due to leukemic infiltrates from true papilledema due to central nervous system involvement.[24]