This subject crops up a lot - it's an "AGE" thing, ya know.
Finding a sight that works for YOU is a very important endeavor - it makes shooting enjoyable.
For target shooting, it is not necessary to go to peep sights. Yes- they are more accurate sighting than with open sights. Some people might use eye sight as an excuse to gain an advantage. I know Harry doesn't, however I'm sure he'll find a wide V with bead to work as well.
Failing eyes see and shoot bead front sights better than blades due to the centre of the 'hazy' sight being the impact- that never changes, but fuzzy blades had varying heights and widths depending on the available light and the angle it is coming in - this changes impact constantly = huge groups. The ball hitting on the bead never changes. The bead has to have a flat, angled surface facing the shooter's eye. That makes it always a round circle that doesn't change position. Some guys find this type of sight helps with failing eyes - I do, even with my corrective lenses (glasses).
The wide V may be a bit fuzzy, but the bead settles into the bottom of the V and sits there - easy to use and get used to. Sure, I'd like to use a peep - tang mounted even better, but make myself use open sights as that is what is acceptable.
The sight Harry pictured above, if cut open with just a 1/16" or even narrower slot on the top surface would stop any complaints as it would then be legal. Pretty easy to do and simple to boot. It still operates as a barrel mounted peep, but is legal for use everywhere. Some people might be too stubborn to do this - Harry?