Are the corners of the table top square, flat, to the rest of the table? Welding the corners to the leg posts usually pulls the corners down.

I'm 43 yrs old, been welding for 25 years. About 5 yrs ago my perfect eye site started going south. Now I'm using reading glasses under my shield, 1.75 or 2.00 mag. I still cannot see the puddle, joint path clear enough to lay down consistent beads. I've tried cheaters but they constantly fog up. I'...