My 1 month old son has one eye bigger than the other. Is he suffering from ptosis and can it be fixed in the future?

He has congential ptosis.  In the pictures, it looks like he is using both eyes and this would be consistent with normal visual development in both eyes.  However, if he begins to neglect the right eye due to the heavy eyelid, this could cause amblyopia or a lazy eye.  It really takes a specialist to be certain this is not an issue and with an eyelid this heavy, this needs to be carefully reassessed to make sure things do not change and there is no development of amblyopia.  The specialist that your son needs to see a board certified ophthalmologist who is also fellowship trained in pediatric ophthalmology.  Yes the eyelid will need to be corrected at some point.  If the eyelid begins to interfere with the normal delopment of the vision in the right eye, early surgery will be necessary to counter act the ptosis.  Please get a second opinion with a pediatric ophthalmologist.

The answer depends if the droopiness is causing problems right now (either blocking vision or causing head to move back).  You have to see a pediatric ophthalmologist along with an oculoplastic specialist. If it is not causing problem, then best to wait until teenage years.