From your description it appears that your mother has had a central retinal
vein occlusion (CRVO). People with hypertension are more prone to developing
CRVO. Visual recovery is usually only partial in these cases. Some patients
can also develop a type of glaucoma, which can be difficult to manage. A
surgery called optical neurotomy is also being evaluated for this condition.
She needs to be under the regular observation and care of a retina
specialist and you have to be patient and accept the fact that visual
recovery may be very limited.