Optic Neuropathy in 10 Patients With Glioblastoma Receiving Bevacizumab

The investigators research will focus on patients prior to them beginning treatment with
bevacizumab (Avastin), by undergoing a baseline visual examination with Visual evoked
Potentials testing. This will allow testing of the patient's optic nerve function
bilaterally. Patients will then begin their normally scheduled treatment with avastin, and
other chemotherapeutic agents, as well any radiation treatments scheduled. Once patients
have completed their treatment with avastin for 6-8 weeks, they will then undergo their
second Visual Evoked Potential testing, with both studies then being compared for any
changes within the optic nerves. Patients will also be recommended to have stringent follow
up with an Ophthalmologist to include confrontational visual field testing, external and
anterior segment examination, and dilated fundus examination. The investigators main
objective is to assess whether or not bevacizumab causes a direct toxic effect on patient's
optic nerves leading to an acute/subacute optic neuropathy.

Inclusion Criteria:

- Diagnosed w Glioblastoma grade IV, and scheduled to begin chemo radiotherapy with
Avastin

Exclusion Criteria:

- No diagnosis of GBM, not scheduled to begin treatment with avastin in combination
with radiotherapy.