When flashlight is moved from normal eye to abnormal eye the affected pupil dilates. What is the MOST likely diagnosis?

In patients with relative afferent pupillary defect in one eye the affected pupil dilates when flashlight is moved from normal eye to abnormal eye. This is called Marcus Gunn pupil and it is an indicator of optic nerve disease. Amaurotic pupil is a total afferent pupillary defect. A complete optic nerve or retinal lesion leading to total blindness on the affected side causes it. The eye has no perception of light. This pupil neither reacts to direct light stimulation, nor does it creates a consensual light reflex in the opposite eye. When light is shone on opposite eye there is a good light reflex in that eye and a good consensual light reflex in the affected eye. Ref: Textbook of Ophthalmology edited by Sunita Agarwal, page 303.