Yes, I do. 

I have an Anschuetz with aperture sights, the rear type of sight you pictured. But let's back up from your question and talk about what are "peep" sights vs. aperture sights, and what sort of sight did you just picture there?

If you look at a Garand, M1A/M14, 1903A3 Springfield, AR15 with iron sights, etc - you have a "peep" sight. Your rear sight will have a fixed-size hole in a blade, and your front sight will be a blade, possibly with sight guards on either side. The Garand, M14/M1A and AR-15 all have blade guards on the front; the Springfield 1903A3 does not. 

The rear sight on a "peep" sight is nowhere near as complicated as the variable aperture sight you pictured there. At most, a peep sight will have two different apertures, one for daytime and one for low light conditions - eg, like the AR-15 with iron sights. You can flip from a "big hole" to a "small hole" in daylight, and back to the "big hole" in low light conditions.

Here's a typical "peep" sight:

http://www.skinnersights.com/apertures_8.html

Many other companies make/made peep sights. Williams, Redfield, etc. The notable issue is that you have only one insert/hole size, perhaps two (eg, the AR-15/M-16), but that's it. You don't get to adjust the size of the hole in the rear aperture as you do in the rear sight iris you pictured.

What you pictured there is the rear sight from a set of "globe & aperture" sights, which is used on target rifles. The benefit of aperture sights is that you can crank down the aperture to a smaller size in brighter light - to gain focus and precision.  Here's a picture of the front sight that would go with that variable aperture:

 http://www.champchoice.com/store/Main.aspx?p=ItemDetailOptions&item=9758

 OK, do you see the slit in the round barrel of the front sight holder? The slot is to the right of the center of the side view of the sight. You unscrew the knurled inner ring (on the right side of the picture above) drop in a sight insert into the slot, and tighten the knurled inner ring down. The sight inserts look like this:

http://jga.anschuetz-sport.com/index.php5?menu=501&sprache=1&zubehoerID=1014&PHPSESSID=a6a7b7be878c80283102234bde67ec8c

Each of those inserts is sized for a particular sized/distance black bull area on a standard target at a regulation distance. There are inserts for 10 meters, 50 feet, 50 yards, etc. The proper front insert will give you a view of the round black area of the target where you see the black 7/8/9/10/X part of the target, surrounded by a thin band of white around it. The human eye is very, very good at collimating round objects - you will center up the black bull in the inner part of the front sight insert, then you'll center the outer part of the front sight insert inside the front sight and then the rear aperture, and when you have the rear sight properly adjusted for elevation and windage, you can lay rounds into the X ring with ease - even at pretty fair distances. Trust me on this - I've done it. When you're just lining up the "black inside the white inside the black inside the white inside the black," and you just work the rifle alignment to make "everything round," you can lay down a group that competes with a scoped rifle.

What you can't do is line up these types of sights on random targets (eg, a deer) worth a darn. They're optimized for shooting at a high-contrast, black-on-white round target - and that's it. That other thing that is difficult to do with these sights is "hold off for wind" - which you can do with peeps much more easily. You can't easily say "I want to hold off three inches to the left, to counter a left-to-right wind effect. Once you get the round bull off-center in the front sight, you will often find your groups open way, way up - because it is very hard to judge "what is three inches?" from holding off a bit left/right on a circle inside a circle. 

OK, so how do these work with aging eyes? I'm the guy to ask, because I started target shooting at a young age with 20/15 vision, still have 20/15 measured at a distance - but increasingly, I cannot focus well on the front sight of a pistol at arm's length, so I'm reduced to optical sights. It's a good thing they measure eyesight ratings at 20 feet. If they asked at three feet, I'd be doomed.  

With an aperture sight, you can crank down the aperture to "increase your F-stop"¹ and gain focus of the front sight more easily - but only in really bright lighting conditions.

Another alternative is the aperture you can put onto your shooting glasses to give you an "increased F-stop," and that's this type of widget:

http://www.bullseyegear.com/bullseyepistol/product.php?productid=69

You now have an adjustable iris in front of your eye. Crank it down to minimal diameter, and your "f-stop" increases dramatically, putting everything into focus in front of you. The downside is that you now need a terrific amount of light to see the target, the sights, etc in front of you. I used a Merit iris on my glasses in bullseye pistol shooting with iron sights on my S&W 41. I surrendered to age and put a optical sight on the pistol recently, and removed the Merit aperture from my shooting glasses for bullseye shooting.

The adjustable aperture you pictured can do much the same thing as the Merit device - just not on your shooting glasses. You can crank it down tight, and increase your focus - but you need great amounts of light.

This is one of the reasons why a proper target range should be situated so you are shooting from south to north - so your targets are always in sunlight (or as much as possible).

So they do work - but only if you have a great deal of light - like shooting from 10 am to 2 pm, on a target that is to your north.

Anything else I can answer for you, please just ask.
 
¹ When I say "increase your F-stop" I'm talking in terms of the sort of optics that photographers will understand. When you have a lens in a camera with a tight aperture and a "high F-stop," what you can do is take pictures where everything is in focus, from a couple feet to infinity. When you have a low F-stop rating, your focus is limited to a very specific plane of focus. When you have a high F-stop, you need huge amounts of light - because your aperture in your camera is cranked way, way down. A low F-stop requires much less light, because the hole through the lens/shutter is so large, it allows in a much larger amount of light.