From your description it seems that your left eye has a convergent squint
. Squint can basically be of two types 1. Paralytic (it comes suddenly due to sudden weakness in your muscles or nerves that control eye movements, associated with decreased movement of eye towards one side and mostly presents as double vision
) 2. Non-paralytic (its is there present from beginning, not associated with any decrease in eye movement, doesnot have any double vision).
Your deviation seems to be non-paralytic one.
this can be corrected by surgery of your deviated eye and if required of your straight eye with results as close to 95% correction. Consult a squint specialist near your home town for opinion.