Snellen Chart Help (Used Online one)

General forum for the UK Keratoconus and self-help group members.

Click on the forum name, General Discussion Forum, above.

Moderators: Anne Klepacz, John Smith, Sweet

User avatar
Arun
Regular contributor
Regular contributor
Posts: 52
Joined: Sun 26 Feb 2006 12:14 am
Keratoconus: Yes, I have KC
Location: London

Postby Arun » Mon 17 Apr 2006 8:52 pm

I think this snellen chart is designed to be viewed from 3 metres. So i don't think you need to multiply it by two.

20/20 is the same 6/6. Just one is in feet and the other is in metres. (I think in theory you would have 3/3 vision but it is the same thing.) But both are great.
Last edited by Arun on Tue 18 Apr 2006 2:19 pm, edited 4 times in total.

User avatar
Lynn White
Optometrist
Optometrist
Posts: 1398
Joined: Sat 12 Mar 2005 8:00 pm
Location: Leighton Buzzard

Postby Lynn White » Mon 17 Apr 2006 9:05 pm

So it seems your vision is better then JB! :)

jayboi2005
Chatterbox
Chatterbox
Posts: 272
Joined: Thu 12 Jan 2006 8:06 pm
Keratoconus: Yes, I have KC
Vision: Contact lenses
Location: Cheshire

Postby jayboi2005 » Mon 17 Apr 2006 9:09 pm

Lynn so 20/20 is good. Im deadly seriouse here, because i don't understand why or how. :?

User avatar
jayuk
Ambassador
Ambassador
Posts: 2148
Joined: Sun 21 Mar 2004 1:50 pm
Location: London / Manchester / Cheshire

Postby jayuk » Mon 17 Apr 2006 9:15 pm

Lynn

May be worth sticking a FAQ on Snelling chart? IF you have the time?
J
KC is about facing the challenges it creates rather than accepting the problems it generates -
(C) Copyright 2005 KP

User avatar
Lynn White
Optometrist
Optometrist
Posts: 1398
Joined: Sat 12 Mar 2005 8:00 pm
Location: Leighton Buzzard

Postby Lynn White » Mon 17 Apr 2006 9:20 pm

JB....

20/20 or 6/6 is very good. It means you have "normal" vision and certainly you are WELL within the legal limit for driving.

From what you say, you are a little blurry on that line but the fact you can get it is excellent.

Quite why things appear to have improved I am not quite sure but don't knock it!

I think I need to take up Jay's suggestion here about a FAQ lol...

User avatar
Sweet
Committee
Committee
Posts: 2240
Joined: Sun 10 Apr 2005 11:22 pm
Keratoconus: Yes, I have KC
Vision: Graft(s) and contact lenses
Location: London / South Wales

Postby Sweet » Mon 17 Apr 2006 10:25 pm

Oh please don't panic! You don't have to be so religious with measuring etc if it is only for your benefit. You can put the chart up and stand at a certain place and then take that as your baseline. Then you can assess future ones from that!

Yes the Snellen chart is still on the site. John and i spent twelve hours updating the home page and info yesterday so if you click on the home page link on the top of this page you will see a direct link to it!

Have fun and 20/20 is fantastic! :lol:

Sweet X x X
Sweet X x X

Image

User avatar
Andrew MacLean
Moderator
Moderator
Posts: 7703
Joined: Thu 15 Jan 2004 8:01 pm
Keratoconus: Yes, I have KC
Vision: Other
Location: Scotland

Postby Andrew MacLean » Tue 18 Apr 2006 10:40 am

20/20 = 6/6

I got that.

I think I also know the formula for converting feet into Metres (thanks to Knight, John, Jayuk, Gareth etc (seriously challenged with sums).

I also understand that 20/40 gives my relative position first and the supposed "normal" second, so that if I were 20/40 I should be able to see at 20 feet what the "normal" sighted person could see twice as far away.

I think I have go9t that, too.

But when some people are given readings like 20/10, does that mean they can see at twenty feet what normal sighted people could only see if they are standing much closer?

I ask because my wife has extraordinary sight.

Do you remember readi9ng about Aristotle? he described microscopic fish that were noly generally visible with the invention of the microscope, and he described the rings of Saturn and Jupiter, having seen them with the naked eye!

Andrew
Andrew MacLean

User avatar
Lynn White
Optometrist
Optometrist
Posts: 1398
Joined: Sat 12 Mar 2005 8:00 pm
Location: Leighton Buzzard

Postby Lynn White » Tue 18 Apr 2006 4:17 pm

Yes Andrew.. it does mean that. In fact many people with not much refractive error can see 6/5, 6/4 or indeed 6/3

It can be rather depressing even to an optom hehe!

I didn't know what about Aristotle! Have you any references I could go look at?

Lynn

User avatar
Andrew MacLean
Moderator
Moderator
Posts: 7703
Joined: Thu 15 Jan 2004 8:01 pm
Keratoconus: Yes, I have KC
Vision: Other
Location: Scotland

Postby Andrew MacLean » Tue 18 Apr 2006 4:47 pm

Aristotle's references to his own eyesight are scattered through his works. His descriptive work on tiny animals and the wandering stars (planets) can be found mostly in his Metaphysics. Aristotle knew of six wanders in the heavens: Mercury, Venus [by implication, Earth, but never specified, although he ought to hve been aware of the work of Aristarchos who had formulated a theory of the orbital motion of the Earth], Mars, Jupiter and Saturn.

He considered good eyesight to be a "virtue".

As to secondary material I suggest any of the standard biographies. books on the philosophy of Aristotle seem to be mysteriously silent on his sight, perhaps because philosophers fail to recognize the significance of his descriptions.

Andrew
Andrew MacLean

User avatar
Lynn White
Optometrist
Optometrist
Posts: 1398
Joined: Sat 12 Mar 2005 8:00 pm
Location: Leighton Buzzard

Postby Lynn White » Tue 18 Apr 2006 5:00 pm

Hmmm OK .....

I do find it rather amazing he could see THAT well and wonder if he had some sort of early refractive aids he didn't let on about!


Return to “General Discussion Forum”

Who is online

Users browsing this forum: No registered users and 46 guests