Hello,welcome to HCM. You have asked questions in two different divisions of the eye disease. Firstly, Double vision 1. After Cataract Surgery- is due to Post surgical stress to your eye muscles causing temporary eye muscle paralysis. 2.Other possible reason could be because of associated medical conditions like Diabetes/High Blood pressure which also causes temporary or long duration muscle paralysis which recovers slowly. 3.Permanent double vision happens due to neurological problems which can be identified and treated only after imaging. Second part is YAG PI-which is YAG LASER peripheral iridotomy done to open up a part of your iris muscle to facilitate the flow of the liquid from the back of your eye to the front to drain,in-order to maintain the intra-ocular pressure. Thirdly,the eye pressure is not only the factor which has to be considered to start treatment,unless it is a potential threat to your Optic nerve(which may cause a permanent damage).On a regular basis,if you do have family history of Glaucoma,your doctor checks the pressure and analysis the structure of your eye nerve (Optic Nerve) and does various tests like Visual field test,OCT ,HRT... if needed,followed by treatment plan.Also if you have narrow anterior part (detected with Gonioscopy test),which may increase the chance of blocking your fluid drain,then it is a must to treat with YAG PI. Hope this answers your questions.