Is anyone familiar with Multiple Sclerosis? Or APD of the eye?!
Question:
Is anyone familiar with Multiple Sclerosis? Or APD of the eye?
Doc says I may have an APD in my eye. Says it's the beginning stages of MS. Does anyone have info on an APD?
Answers:
Afferent Pupillary Defect (APD) or Marcus-Gunn pupil is a condition of the eye where the pupil doesn't dilate appropriately to the level of light reaching it. This will often result in one pupil appearing larger than the other (relative afferent pupillary defect - RAPD). This person with APD is often unaware of it except by looking in a mirror.
There are many causes of APD including Optic Neuritis (ON), glaucoma and optic nerve tumor. In multiple sclerosis, APD, is usually associated with damage to the optic nerve resulting from ON.
The reasons why afferent pupillary defect occurs with optic neuritis are complicated. Basically, the eye in which the ON has occurred acts as if it is in a lower light situation than it really is and dilates more so that it can let more light hit the retina.
Optic Neuritis is a condition where the optic nerve swells and signals do not pass well down it. In more than 50% of cases, ON is caused by MS.
Your doctor will probably start testing to determine what is causing your APD, ruling out other causes besides MS.
If you'd like more information about any of this, please let me know.
HTH
CJ