I have no idea what this is

[starfish86]

Slightly scared to ask this, but since autumn I've kind of noticed that when I focus on something in the distance (relax my eyes) and turn my head quickly so that my focus winds up in either the extreme left or extreme right of my vision, I can see a very faint sort of semi-circle of shadowing. I can do this with either eye closed or both eyes open, so it's bilateral. I get two faint patches if I do it with both eyes open.
I do spend a lot of time at the computer, but I've never had an eye exam. I do notice that I have aching eyes at the end of the day. I'm a medical student so I have spent a lot of time straining my eyes with the books and computer screens this year (but I'm also aware that I might be prone to hypochondriasis). Is this something that's normal, or could be caused by muscle strain? I'm scared it's neurologic. I don't present with any difference in my peripheral or central vision normally, and my hand-eye coordination is still above average so...I just don't know. I had an MRI (as part of a paid research thing) and as far as I know nothing abnormal showed up...

I don't have health insurance but I have access to the NHS from August.

[Michael J Kutryb, MD]

If you have good vision and no complaints with your vision, you can easily make this happen and go away if you want, no double vision, no eye pain or discharge, no flashes or light or floaters then I really don't see what the problem is.  Your symptom didn't really bring to mind anything I could think of except that you are quite observant.  If you are concerned about this phenomenon, then make an appointment with an ophthalmologist which is a good idea anyway since you need good healty eyes with your vocation.  Take this symptom as an excuse to get your eyes checked out and in the meantime don't worry so much about it.  If you have a concern about something, write it down, and have it checked out.  Anxiety problems can occur if you just hang on to it.

[starfish86]

That's actually really helpful. A classmate had to drop out because he developed Leber's Hereditary Optic Neuropathy at the start of the year, so I was hoping I was just observing something that was always there and his situation made me paranoid.

I'll get my eyes checked in September! Thanks again.