For background. I work in the print industry. I wear corrective lenses to ensure that what I am printing is indeed accurate and precise. My vision is excellent until I need to focus on the FRONT SIGHT quickly. I have even had my prescription changed in the attempt at trying to alleviate this problem to no avail. I am now using the same prescription that works in all but this instance for the last 20+ years after significant cost to correct the front sight issue.
As a result I realize that absolute accuracy for me at least will not happen. After accepting that fact my focus since has been muscle memory for the most part and quite extensive repetition of the draw stroke and aiming to achieve combat effective accuracy (8 inch group at 10 yards). My standard. Some would call it point shooting, which it is not as the angle of and level of the gun are in focus but the sights are not clearly defined. My goal is always a combat accurate first shot within 2 seconds from the holster. Surprisingly I have also become quite proficient after much practice at effectiveness on a silhouette from two handed retention fire as well as one handed fire from clearing the holster at 5 yards.
No doubt there is nothing more accurate than sighted fire. For those of us with visual limitations wanting to defend ourselves as well as others though I have found there is another method.