How are you? Are there other symptoms present? It is best that you have this checked by an ophthalmologist for proper evaluation. Your medical history, age, and direct clinical examiantion is important. It could be problem with the optical nerve or issues with the retina,cornea and other parts of the eye. Treatment will depend on the underlying cause. Take care and do keep us posted.
Have you had any injuries to your eye or head or face? When was your last eye exam? It could be a retina problem, so many things. I would get an appt with an eye doctor, at least an optician preferrable an opthamologist.