<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have been experiencing some symptoms with my eyes lately. They feel heavy and I have trouble seeing at times. What could be the problem?  <response>: Based on your symptoms, its possible that you may have an Ependymoma - a brain tumor that can affect the optic nerve causing vision problems. We will need to carry out some tests to confirm. 