Please get an mri  brain  done. As the optic atrophy  might be a part of cerebral atrophy or some other cerebral pathology.

Ask the operating surgeon for a detailed report of his eye condition before and after surgery . Then use that to take a second opinion . Maskatieyeclinic Opposite Charni road station east, Mumbai

As your doctor has informed his vein has dried it could be vascular occlusion. Was his vision better before cataract surgery. If he had a very poor vision prior to cataract surgery then it could have been preexisting. Please check with your doctors prescription about the status of pupillary reflex, grade of cataract and fundus findings before the surgery to get a more clear idea of preexisting or otherwise situation.

Hello This could be due to optic atrophy But optic nerve takes Atleast 6 weeks to get atrophied Moreover there must a cause for optic atrophy Cataract Surgery has no relation with this condition Having said that it is provisional diagnosis Kindly share your case file so that I may guide you better Regards

As per the history mentioned by you, it could be an 'Optic atrophy' of the eye which got cataract surgery recently. An Optic atrophy is explained in a simple language as dried nerve and if that's the case then visual recovery is difficult as there is no treatment for optic atrophy.