dont know what its like around the world,
lots of people in europe wear glasses / have contact lenses
ever year or two we go off to have eyes tested.

eyes meassured in dioptre .
wonder what the realistic resolution of the opticians messurment is ?
seems every time , i need a new perscription, and each time up or down 1/2 dioptre !

unfirtunatly, i dont have numberes over years, but if all had been in same direction, id be at plus 15 , or minus 15, not the 1.5 im on !

Has feeling of ways to make money to me

anyone know how accurate / repetable day to day the opticians test is ?

 

Well, you can certainly self evaluate it. Either you see better with the new prescription or you do not. At 73, my prescription has not changed in years, and recent changes have been very small.

 

1.5 isn’t very much. I have always been myopic (short sighted) getting worse with age. I didn’t have glasses until I learned to drive and couldn’t read car number plates at the required distance. My first glasses were -1.5 and I only wore them for driving. If you are long sighted you can buy reading glasses inexpensively without a prescription try 1.0 reading glasses and put them in front of negative dioptre glasses to check if “better or worse”

 

Download and print this test page. Follow the instructions on the page.

 

I'm myopic as well. There was a period of time in my 30's into my 40's where my prescription did not change. Somewhere around 50 my far vision started getting better and my near vision worse. In fact, the prescription difference with a 10 year old pair of sunglasses is so bad, it was causing headaches.

 

getting worse with age

Yep. I had an optometrist visit this morning at my local Veteran's Administration. Slight change from a year ago but not much. I was maybe 46 when I noticed reading tiny components was getting worse. Today at 76 my vision, fortunately, is not all that bad. No clue on the diopter numbers. Did have a cataract removed a year ago on my right eye. Nothing really new as of today's visit.

Ron.

 

any one know an optician ?
Im wondering whats the smalest difference in perscription they can reliable detect ?

 

any one know an optician ?
Im wondering whats the smalest difference in perscription they can reliable detect ?

My daughter is an optometrist. I can ask her.
Note that prescriptions go in increments of ±0.25 dioptres (diopters in US).

Edit: There is a difference between dioptres and magnification. I have to confirm that ±0.25 figure. I could be wrong by a factor of 4.

 

As far as I can read, for prescription glasses, they use diopters and magnification interchangeably.

For magnifying lenses,

Magnification = (Diopter / 4) +1

 

has anyone had a diopter of 1/4 or 3/4, seems here the smallest step is 1/2

 

has anyone had a diopter of 1/4 or 3/4, seems here the smallest step is 1/2

Yes. I have.

 

Download and print this test page. Follow the instructions on the page.

my vision has declined over the past few years. my eye doc is impressed, she tells me that i am luckier than most people. maybe so... but i can clearly tell the decline. so i printed that test page on 8.5"x11". i can clearly see all lines from distances 3" to 6ft. for her that would be proof that my eyes are fine and i should be happy. sigh...maybe so... but she has no idea what my eye sight used to be. and i want it back...

 

the way i understand it, the problem at the heart of presbyopia is that dynamic lens wears out and becomes stiffer. this increases strain on ciliary muscle and limits range in which lens works.

common eye surgery is reshaping cornea (LASIK etc). it is reshaping the external rigid part... this is essentially hiding glasses into ones eye. but while this is cheap and provides relief, it does nothing to address the actual issue wear of the dynamic lens. in other words it provides temporary relief by making certain focal length more comfortable... for a while. dynamic range is not improved, aging and stiffening of the lens continues and eventually one may still need glasses. on the plus side, this is cheaper ($500-1000 per eye)

the better surgery is so called Refractive Lens Exchange (RLE) which replaces the stif lens with synthetic one. this costs more (some $5000 per eye or 5-10x more than LASIK & co.) on the plus side, this is a permanent fix since replacement lens stays flexible for life and one maintains wider dynamic range.

is my understanding correct?

 

I was just wondering why the results seem to go up / down alternate years needing new glasses !
If I'd realised earlier , I'd have kept old glasses !

 

The eye test results can change based on a number of factors, some of which can vary over short periods of time. For diabetics, taking an exam when your sugars have been very high can yield noticeable changes and lots of optometrists don't like to do a test if your sugars aren't under control, but even non-diabetics can experience quarter to half diopter shifts, usually toward myopia, from a high-glycemic meal. Then various drugs have an impact, particularly blood pressure medicines and antihistamines, but I'm sure there are specific drugs that have even more impact. My understanding is that if you were to go to a bunch of different optometrists one after another, the results would likely vary by a ±0.25 to ±0.5 quarters across them, with the "is A better than B" type tests being more variable than ones using automated measures.

In my experience, the last thing the doctor usually does is switch back and forth between your current prescription and the new prescription so that you can evaluate whether it is worth getting new glasses.

 

The eye test results can change based on a number of factors, some of which can vary over short periods of time. For diabetics, taking an exam when your sugars have been very high can yield noticeable changes and lots of optometrists don't like to do a test if your sugars aren't under control, but even non-diabetics can experience quarter to half diopter shifts, usually toward myopia, from a high-glycemic meal. Then various drugs have an impact, particularly blood pressure medicines and antihistamines, but I'm sure there are specific drugs that have even more impact. My understanding is that if you were to go to a bunch of different optometrists one after another, the results would likely vary by a ±0.25 to ±0.5 quarters across them, with the "is A better than B" type tests being more variable than ones using automated measures.

In my experience, the last thing the doctor usually does is switch back and forth between your current prescription and the new prescription so that you can evaluate whether it is worth getting new glasses.

do you find when they do thst its all but impossible to detect the difference, yet they always seem to select the 1 /2 dioprer difference lenses !

 

probably as part of preventative maintenance plan - you will get there eventually.

 

To make light of the conversation, I just keep 3 or 4 different power cheaters on my desk and choose the one that I need for a task.

I only need +1/2 or 3/4 for reading at a comfortable distance, but I'll go up to +3 for close technical work or fine, low contrast print (i.e. legal disclaimers).

 

dont know what its like around the world,
lots of people in europe wear glasses / have contact lenses
ever year or two we go off to have eyes tested.

eyes meassured in dioptre .
wonder what the realistic resolution of the opticians messurment is ?
seems every time , i need a new perscription, and each time up or down 1/2 dioptre !

unfirtunatly, i dont have numberes over years, but if all had been in same direction, id be at plus 15 , or minus 15, not the 1.5 im on !

Has feeling of ways to make money to me

anyone know how accurate / repetable day to day the opticians test is ?

Got mine tested as soon as I turned 60 and it became free on the NHS. My prescription hadn't changed since I first got my glasses. The optician told me that it wasn't a good idea to keep strengthening the prescription as it encourages the eye muscles to deteriorate. I ordered some prescriptions safety glasses here.

 

To make light of the conversation, I just keep 3 or 4 different power cheaters on my desk and choose the one that I need for a task.

I only need +1/2 or 3/4 for reading at a comfortable distance, but I'll go up to +3 for close technical work or fine, low contrast print (i.e. legal disclaimers).

Further, I used to be near-sighted, but my age has nearly completely corrected that save for a very slight astigmatism.