# Basic Eyeglass Question



## aesmith (Aug 7, 2009)

Hi,

Nowadays I need to use reading glasses, which is a pain in the backside. What I was wondering about is how this interacts with the properties of an eyeglass magnifier.

If I remember rightly, a standard microscope eyepiece is made so that the eye focuses at infinity, considered to be the most relaxed state. Accordingly, that would mean that one would use the microscope without reading glasses.

Is that also the case with standard eyeglasses, that they work with the eye at infinity?

Cheers, Tony S


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## Roamer Man (May 25, 2011)

I don't know about working to infinity, my GCE O Level physics was a very long time ago. What I do know is that for a simple eyeglass it doesn't matter what condition your eyes are in, they work at short focal lengths. In the case of more complex optics (e.g.the ocular eyepiece of microscopes, cameras etc) they do need the extra ocular adjustment facility to cope with long, and short-sighted users.

In short, I don't have the definitive answer to your question!


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## bsa (Dec 23, 2010)

Without any technical info and with my failing eye site i work with my watches using a headpiece that is about 10 and 20 mag with light.

I find this less straining and clearer when not combined with my prescription glasses.

Mark


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## aesmith (Aug 7, 2009)

Thanks guys. I think I'll get the holder and a mid-range magnifier to start with. 10x sounds too high for what I want, which is to be able work hands-free on things that are too small to comfortably view even with reading glasses.

I found a convenient cross-reference between magnification and viewing distance on Cousins' web site, according to that 2.5x equates to 4" distance, that will do for a start.


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## Roger the Dodger (Oct 5, 2009)

I wear reading glasses (+2.0), but I find I don't need them when I use an eyeglass or a loupe...in fact the view is worse if I try to use my specs with them.


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## William_Wilson (May 21, 2007)

I place my reading glasses over my bifocals and then look through an 8X loupe when I really need to see tiny screw heads. 

The distance from my eyeball, with that rig, is about 2.5 inches.

Later,

William


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## aesmith (Aug 7, 2009)

Roger the Dodger said:


> I wear reading glasses (+2.0), but I find I don't need them when I use an eyeglass or a loupe...in fact the view is worse if I try to use my specs with them.


Having tried, I find the same. The pay-off is the hassle of taking the glasses on and off.


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## Mechanical Alarm (Oct 18, 2010)

These are my all-time favorites - amazing build and optical quality from Wetzlar Germany (read - not cheap!). These are 3X and do everything I need them to except the fine jewelery inspection where a 10x or 20x loupe is a must. They have a great working distance of about 10-12". I find myself working and wearing them all the time and constantly looking over the tops to see other things and converse with people. 1st timers seeing me think they are quite weird - till they try them on!


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## aesmith (Aug 7, 2009)

Mechanical Alarm said:


> These are my all-time favorites -


Those look brilliant. I guess they're not a simple lens if it gives a viewing distance of 12" for a 3X magnification.


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