Optic Nerve Glioma
Optic nerve gliomas are slow-growing brain tumors in or around the optic nerve. Optic gliomas are rare and even though, the cause of optic gliomas is unknown, they have a better survival rate. They are more common in children with a genetic condition called neurofibromatosis 1 (NF1). In the majority of these cases, these tumors are indolent.
The most common symptoms of optic nerve glioma are listed below:
Vision problems such as squinting, difficulty reading, or turning to see things out of the corner of the eye.
Proptosis (eyeball protrusion) occurs when the tumor has grown to the extent that it pushes the eye outward from the socket (an eye with proptosis has very little vision).
Hormonal problems, including abnormal growth, weight gain or loss, endocrine dysfunction (such as having to urinate frequently), or early puberty.
Optic nerve gliomas are typically diagnosed using a combination of imaging and vision testing.
The following investigations are necessary for confirmation of diagnosis:
A complete physical examination
Computed tomography (CT or CAT) scan
If a child has neurofibromatosis 1, vision is followed closely
Magnetic resonance imaging (MRI)
Treatment is based on many factors, including their age, overall health, and medical history, as well as the tumor’s characteristics and extent of the tumor. The current standard chemotherapy for optic gliomas consists of vincristine and carboplatin (commonly termed the ‘‘Packer regimen’’). Other than the conventional external beam radiotherapy, new techniques of delivering radiation, including fractionated stereotactic radiotherapy, proton beam radiotherapy, and more recently stereotactic radiosurgery have been used in the treatment of optic nerve glioma in the hope of minimizing the risk of radiation-induced side-effects. Surgical resection is usually limited to cases in which the tumor is confined to one optic nerve or is causing progressive blindness or disfiguring proptosis. The goal of the management of optic nerve gliomas is to ensure the preservation of vision over the long term to improve the quality of life of the patients.