It depends on the intended use of your pistol and the condition your eyes are in.
If the primary use of the pistol is for defense purposes I recommend leaving the sights as is.
The reason being, most defense sisuations will be up close and personal and you most likely will not need the sights.
If it's just a range gun for shooting targets using a 6 oclock hold you may want to go with a low mount Bo-Mar adjustable type sight like salvadore has on the gun in the picture.
Many times those with aging eyes find that bigger sights do not help, as a matter of fact many realize the larger sights just obscure more of what they are trying to hit.
I know all to well about aging eyes and pistol sights.
I've actually found that I shoot smaller sights like the ones on the original 1911 better then I do larger sights.
Also 1911A1 sights with colored reference points on them seem to work well for me.
The old King-Tappan rear with the white vertical line under the rear sight notch and a white dot up front is as good as it gets in my opinion.
It gives a sight picture that looks like this [ i ].
Before you spend a lot of money on adding larger sights that may not work for you, you may want to try adding reference marks to the sights on your pistol if they do not have any.