The standard eye test

[Barney]

Was wondering if anyone had come across anything more sophisticated than the normal eye test using the Snellen chart?

By tilting my head around and concentrating I can see to somewhere around the 20/40 line with my "bad" eye but I don't think this is much of an indication of how well I can see in practical terms. There isn't any time limit so although I see multiple images I can eventually make out what the letters are - especially as the shapes of the letters are well-known to me. As my sight gets worse with more ghosting it may take me longer to recognise what I'm seeing but may be able to read just as far down the chart.

But the real world isn't full of black letters on a backlit screen. The shapes I have to see are complex in all colours and tones and often I won't have seen them before. Often I'll need to pick out a shape from a complex background of other shapes and for tasks like driving the speed of perception is all important.

Seems to me that that the normal eye chart is really only suitable for telling how well eyes can focus. My eyes focus fine, it's the other difficiencies that cause the problems. The test is always for middle distance too and I've never been tested for being able to read. There isn't any assessment of how sight might vary under different light levels such as in bright sunlight.

Does anyone else feel the the basic test and eyechart as currently used doesn't really give a useful assessment of how well someone with KC is seeing and know if there are other methods around or any being researched?

[Anne B]

I agree with you Barney.

I can work out letters on the eye chart , but i am not seeing them clearly and have often felt it is not a fair assesment.
Also if i really squint letters become clearer, and have done this during a eye test.

Anne

[GarethB]

Whenever I have had my eyes tested, I have had to do the usual and look at an eye chart, tagets on different colours, radiating lines in a circle, a hand held chart/text afair to see how I would read normal text and more besides. That was just the normal high street optom and I have the same thinga t the hospital too plu in all cases the obligatory examination under the slit lamp.

Any eye test has menat I have been with the optom for at least an hour.

[Barney]

Which hospital is that Gareth? Sounds more thorough than I've ever had. I go to Moorfields once or twice a year but have never had any optical test apart from the standard chart. Last time I was there they mentioned for the first time that I had a cataract but there doesn't seem to be any way of assessing how much of a part it has in affecting my sight.

I sometimes idly test how my sight has changed by looking at a streetlight and judging how far apart the multiple images are. Would have thought something similar could be done by the hospital to measure progress. Once had a topography thingie done but that was by a youngster who wanted to try the machine out.

[GarethB]

The hospital was Cov & Warwick which has now moved into the Walsgrave Hospital in Coventry to make one big super hospital so there should be loads of new equipment.

My optician beforre that was PJ Hanby in Rugby, now Scrivens, but Mr Hanby is there sometimes when he is not being the head optom in outpatients of St Cross Hospital in my home town of Rugby. Sometimes bump into him at the main hospital in Coventry.

[Andrew MacLean]

I'm like Gareth: the Snellen Chart is part of the eye test I go through (both at hospital and in the High Street) but it is not the whole test.

Andrew

[Matthew_]

I used to pass my yearly diver's medical by wearing my soft lenses for the eye sight test and not telling anyone. When the my KC kicked in (and I couldn't read the chart even with lenses)I found that I could remember all the lines anyway! Shame on me. Eventually I realised it was better to come clean.
I think it goes to show how 'dumb' the snellen test is in that it measures plain va and nothing else. At my high street opticians, I got pressure tests, peripheral vision, colour perception, snellen test and a reading card. At the eye hospital I got a snellen test, pressure test, reading card and a corneagram.
I think there has to be a doctoral thesis in developing a KC test. Perhaps it might be possible to put keratoconics on a scale, like a KC score? The score could be based on how many images you see, or halo effect at night or a combination of factors. Wouldn't be easy because of the complexity of KC but I wonder.....

[Andrew MacLean]

Matthew

You remind me of what I used to do as a schoolboy. Wearing glasses in those days was not at all cool: I guess the price I paid for growing up in the years before Harry Potter.

When standing in line waiting for it to be my turn to stand with my toes on the line in the "nurse's room" floor. I would listen to what my friends were reading out and make up a story, with each letter on the chart as initial letter of each word.

My name begins with "Mac" (a Scottish eccentricity that need not trouble those of the incognisanti) meant that I was pretty far down the alphabetical list, so I had plenty of time to rehearse inwardly my mnemonic tale.

I always passed with flying colours, but could not see the blackboard. Still, seeing the blackboard was not the object of the exercise.

In the end I got found out. They split my class into A-L and "Mac"-Z

I was first up. That year my sight was very poor indeed. I had to wear glasses. All this happened just at the wrong time.

Still, I eventually recovered from the indignity.

Andrew

[Matthew_]

I feel for you. None so cruel as children!

[Sajeev]

The eye chart test is not a good reflection on how KCers see... you may be able to see a letter... but how good? can you see anything else? It varies from different eye test rooms as well due to the different lighting.

I have been tested with not letters but different shapes that get smaller and smaller (its impossible to guess then), letter shown one at a time, glare tests, contrast tests, a test with lines which tests for astigmitisum, field of view tests which is done by you clicking a button when you see a random moving pattern with in the stimulator screen you are looking in to.

This all helps with knowing if your vision has changed, and for better correction, I think.