I wonder if the problem I had is similar for your (think it might be similar because I also have blurred vision at night i.e. tail lights on cars, so try to avoid night time journies), may not be but worth a go - I am left handed and suffer very poor astigmatism in my left eye. 3 putting was a regular event for me, until I went to see a coach who concentrated on the compatability of information received by both eyes - unless there is consistency in this respect, its unlikely that you will ever feel confident about the right line (as one eye is kind of contradicting the information from the other) We all have a leading eye which we tend to 'go to' usually but its difficult if not feeling 100% confident (backed up by corroborating data).
My coach got me to try this:
First you need to determine if your eyes are giving you the same information, and if you wear glasses and suffer from astigmatism this may not be the case, particularly if you don’t wear your glasses on the course - Try this technique:: simple rule is focus on an object and then close both eyes, then open each eye whilst the other is shut. Do this rapidly whilst continuing to focus on the object (a line of text or a heading on the computer screen at eye level (when seeing it with both eyes is best) works well. Are you seeing the object on the same horizontal plane for both eyes – if not…….
Try tilting your head to the point where your eyes are seeing the object on the same horizontal plane – where your head is tilting is where you should place your ball in your stance for putting – For many people with astigmatism, this compatible focal range lies outside of their stance particularly if you have significant astigmatism in one eye. It’s a common mistake among golfers that they think it should be in the centre, however unless you have correlated compatible data from both eyes you will never be able to putt like a pro!
Try it and see, it may not be your issue but if you do see the object on differnet planes, then have a play around to see where the ball should be in your stance that then gives you the consistency you are looking for. My compatible focal range is 2.5 inches beyond my left foot. To compensate for the adjustment in my stance, I draw this foot back a little to ensure I have a smooth stroke.
Last year, my handicap went from 19.2 to 13.7 and it was all down to my putting - I am now making more birdies and have cut the three putts down from 5 or 6 a round to 1, or 2 at most.
Give it a go and let me know how you get on - it may be that what works for me is because of the nature of my astigmatism, but the principle remains the same until you have focal compatibility from both eyes when you are viewing a target, the chances are doubt will still cloud the issue., and that ain't good for reading the right line.
I would be interested in your feedback