As I have gotten older my ability to see details up close has gone to the dumps. I’m sure that there are at least a few of you out there who have experienced the same thing. OK - not a few - this applies to anyone over 50.
You have been there. When attempting to solder 0603 LEDs I was guessing where the lead should go. When I was attempting to install parts like grab irons I could no longer see the hole clearly, and on and on…
There is a solution. A few weeks ago I invested in an Optivisor by Donegan Optical. Now I can clearly see the little stuff. In fact, I have the thing on my head now most of the time that I am at the workbench.
Donegan offers a variety of products with various magnification levels and two different lense materials - optical glass and acrylic. I opted for the optical glass (pardon the pun) with 2.5X magnification. That means that things are in focus when they are held at about 7 -8 inches from the lense. The company recommends using the lowest necessary magnification that suits your eyes, but the 2.5X suites me very well.
You will also need a good light source. Donegan offers a single bulb ‘headlight’. I opted (there I go again) for a lighting system made by Quasar which has six LEDs mounted in a frame around the lenses. I am not happy with the Quasar product. Six LEDs sounds like a lot of light but in fact when you are working at a distance of eight inches only one of the LEDs is actually shining on your work. I even changed out the rather blue LEDs that came with the Quasar product to bright white LEDs but it made little difference. I am considering investing in the Donegan lighting system because a single focused light source now makes more sense.
The usual caveat - I am not affiliated with Donegan in any way except as a happy customer. Words can hardly explain the difference the Optivisor made in my modeling
The main reason you don’t see very well as you age is that the pupil, or iris, loses its ability to dilate in low light. Children can dilate their eyes around 7 mm in diameter, but men past 55 rarely exceed 5.5 mm. The smaller diameter means a smaller aperture allowing light to fall incident on the light sensing area at the back of the eye. Using the formula for the area of a circle, or a disk more correctly, which is 2Pi X (radius), we calculate that whereas a child’s eye has 43 square mm of cross-section, or aperture, a middle-aged man will only have 34.6 sq. mm, a reduction amounting to nearly 20% in light gathering power. This presents two problems…less light to see, but also a lesser ability to resolve detail due to the smaller aperture not providing sufficient resolution. Resolving power in an optical system is its ability to show separately two similar objects placed very close together. If you printed a white page with only two periods on it, no spaces, and walked 50 yards away, held it up, and asked your mother if she could tell how many dots there were, she’d not have a hope. Give her some 7 X 35 binoculars, though, and she’d have a chance. The binos gather 35 mm of light at the front and provide enough resolution to show the two periods cleanly split.
Working in normal light, or even in bright enough light to cause a middle-aged man’s iris to shrink, he’d have trouble seeing the dark tiny holes on a Walthers Heavyweight passenger car in Northern Pacific livery that were meant to house the ends of a tiny grab. Using an Optivisor magnifies the view and allows the viewer to see the details larger and more defined.
I got an Optivisor right away when I entered the hobby, and I believe the magnification is 2.5.
Worse than that, actually. The area of a circle is Pi r-squared, so the decrease in aperture is not 20%, but over 38%.
I’ve got bifocals, and I’ve had them for several years now. For whatever reason (denial, ego) I resisted for a long time, but now that I have them, I really like them.
For detailed train work, though, I use a desk magnifier lamp, a cheap one I got on sale for about $16. This give me the light and magnification all in one convenient package. I don’t typically do detail work directly on the layout, always on the workbench, so I don’t have an issue with needing to find somewhere to put the desk lamp down.
[#welcome] to the optivisor group, Dave. What took you so long? [(-D]
My optivisor and task lamp are THE two most used tools in my MRRing tool arsenal. If I’m sitting at my bench - more likely than not - my optivisor is on my head. And my set of tweezers (fine-nose, broad-nose, and locking) are a close third.
As we get older, we lose the ability to focus because the goo in the lens stiffens with age and the muscles no longer have the strength to change the shape of the lens sufficiently to focus throughout the entire range. That’s why bi- and tri-focals become necessary.
I, too, have to remove my glasses to see close-up.
There is a surgical procedure wherein the goo is sucked out of the lens and an artificial material is injected. My optometrist had it done several years ago, and he swears by the results. I’m planning on having it done one of these years, as soon as I can save up the funds.
Be sure you get the genuine article when looking for an Opti-Visor. The el-cheapo ones from places such as Harbor Freight have very poor quality lenses in them.
Mr. B, yup, I got the formula wrong…what I posted was for the citrcumference. When I posted that late last night, I couldn’t see why the reduction in area I had calculated was so much less than what I knew it should be, but was well past the time at which I could spot my error. My apologies to those who took my error for veracity.
So, yes, as Mr. B correctly posts, the reduction in light-gathering is much less with the aged adult eye, and that’s the point. Nearly 40% less light for the brain to use to make sense of what it is ‘seeing’.
I’m am both glad and sad to find that I’m not the only person over 50 who can’t see anymore when it comes to fine detail work. I have an illuminated magnifying ring at my workbench, but I guess I’m going to need to purchase an Optivisor to use for layout work.
A few years ago I was having trouble installing switch machines under my layout. With the graduated lenses in my glasses I could never get my head bent back far enough to hit the correct focul point in the lense. In frustration, I went to my eye doctor, held my arms out at the appropriate working distance/angle for installing switch machines and told him “give me this,” to which he responded “I can do that.” With the special mono-vision lenses I can now accurately and rapidly install switch machines again. Of course, I can’t see to do anything else with the special glasses, but with about 100 more switch machines to install, I will put them to good use.
Why is it that posts to a thread talking about not being able to see small parts are being posted in smaller and smaller fonts sizes?
All I know is I used to laugh at the whole idea of Optivisors, not to mention their appearance. Then I started wearing cheap drugstore reading glasses a couple of years ago, and am now a slave to them. I’ve recently started using my magnifier desklamp along with my readers. That Optivisor ain’t looking too bad any more…
The server seems to take the settings that appear in the post that the subsequent poster replies to, or maybe the OP’s…not sure.
You can change your own font size in the task bar at the top of each post if you see that it is too small for your liking. I saw what this one looked like, entered ‘edit’, and have ajusted this to size “3”, which you see now.
What I have to do for this process is place the cursor at the end of the text and punctuation, right click and slide back and up to the upper left of the text to hilight it. It doesn’t work for me starting at the top and sliding lower right for some reason. Then, with the text hilighted, select font size you want, three in my case, and save the changes.
Great post Dave. I have one of those items and hardly ever use it but now that I’ve officially reached "My golden years"and Cataract surgery on two eyes that t wiurned out less than great I need them!!!
You post reminded me that I have a pair with lights. I’m going to dig them out Today.
Now if some one would just come up with a cure for shaky hands, life would really get better [:D]
Brunton been there, done that. I still can’t see very well and I still have to wear Tri focals. Some times the surgery does not work as advertised. [:(]
Dennis, my first great hobby love was astronomy and telescopes. I did some reading over the years about optical systems, of which the Mk 1 eyeball is an example. One of my annual purchases used to be the famous (in professional and amateur astronomer circles) Observer’s Handbook that the Royal Canadian Astronomical Society publishes annually. This problem with the aging human eye is/used to be described well in layman’s terms early in each edition. My memory, if not my math formula dexterity, seems to have it all there after many years.
One of the key criteria for seeing well with any optical system is how much light it can focus and slide through the human iris and on back to the photo-receptors lining a small area directly in line at the back of the eye. While it is complicated, the big thing is getting lots of light, and that can only be done with a wide aperture…a BIG hole.