Why do pupils not react to light?

[meikman]

My son is 15 and has been seeing gray shadows in the background of his vision.  His opthmalogist referred him to a Neuro who examed him and said his pupils weren't reacting to light then showed me what he saw.  He wanted a drug test done which was done before we left the building.  

The Dr then wanted a MRI which the eye dr didn't think could be done because of his braces but Neuro said it needed to be done then he said that there was another test that he would have done if the MRI came back normal.  He left the room to order the test then came back and said that he wanted this test done anyways and that it was to check if the eye and nerves where working correctly.  He said that it was visual invoked potiential.  I know that this is a test that is normally done for MS.  Could he be thinking that it is a possiblity?   Why else would someones eyes not react to light if not due to drugs or brain injury?

[Quixotic1]

Hi, there!  We haven't talked for a while.  No, the VEP is done for any disorder in which there is a visual problem, to assess whether the eye-brain is detecting and processing images promptly and fast enough.  It is NOT a test directed specifically looking for MS.  I can't answer the rest of your question, or at least shouldn't, because to discuss all the possiblilities would be foolish.  Your son's doctors are doing a progressive work up and I would leave it in their hands.

Let us know what develops.  Quix

[meikman]

Thank you for your response.  

The Dr kinda throw me.  I almost didn't take my son to his appointment.  My son didn't want to go he decided that he was ok and I wasn't looking forward to go downtown in the nearby metro. but decided it to be neglectful not to take him and let the Dr say there is nothing wrong as I am sure that is what we'll here when this is over.  Patience isn't always my virture.  It is going to take sometime before we get an answer.  The Dr wants us to come back in a month to discuse the results of the tests.

I fixate on the pupils because the only thing that came to mind is drugs and brain injury which the drug screen was neg and my son only "brain injury" was a concussion he substain when he was 4 when he slipped on a wet smooth cement floor.  It did knock him out but very shortly and he only spent one night in the hospital.

[Quixotic1]

I'll look up and try to do some reading to see what I find.  Are both pupils nonreactive?  Are they pinpoint or of normal size and don't get smaller with light?  Do they widen with dimming of the light?  Quix

[meikman]

I have too try searching the net but haven't came up with much at all.  His pupils I believe are normal size, they just didn't get smaller when light was flashed in his eyes.  When the Dr shown to me what his eyes where doing or should I say not doing, It looked as if his left bounced just a bit but his right eye didn't move at all.

Thank you so much for your help.