Test your own eyes

[Bomber Harris]

Here is a method of making your own eye chart to see if you make the grade for your class one. Of course they test for a zillion other things on the actual medical, but this is a good home made test to be used for what it is......a home made test for shortsightedness only, carried out by oneself with, I assume, no medical expertise whatsoever. (That’s the disclaimer for the types that dry their wet cats in the microwave).

I will assume you have a computer with Microsoft Word and a printer with a basic understanding of same (well you are reading PPRUNE). Open Word and set the font to Arial with BOLD switched on. Go to options and switch on the 'ruler' so you can see a height measurement panel on the left side. In the general tab in options select measurement unit as millimetres. What you need to do is type in a selection of letters making them progressively smaller as you see in your optitions charts. This is what you are aiming for
line 1;strength 6/60; height 87mm; suggest font size 348
line 2;strength 6/36; height 52mm; suggest font size 208
line 3;strength 6/24; height 35mm; suggest font size 140
line 4;strength 6/18; height 26mm; suggest font size 104
line 5;strength 6/12; height 18mm; suggest font size 72
line 6;strength 6/9 ; height 13mm; suggest font size 52
line 7;strength 6/7.5;height 11mm; suggest font size 44
line 8;strength 6/6 ; height 9mm; suggest font size 36
line 9;strength 6/4 ; height 6mm; suggest font size 24

Print this off and measure what you've got and adjust as necessary. Then hang it on the wall in a well-lit room and stand 6m away. Cover one eye and read it. Then the other eye and read it backwards. You need 6/9 in each eye independently and 6/6 with both eyes together. You can wear lenses up to a maximum of 5 dioptres to achieve this.

To make a bit more professional looking, select the entire document and centralise the characters. Then select font size 10 with the cursor at the end of a line and hit return, then type in the strength for that line eg 6/24. Repeat this for all the lines.

FAQ
1/ but somebody said that I need 20/20, what does that mean?.....If you cannot convert between meters and feet then don't become a pilot
2/ yes, 4 points of a Aerial bold is about 1 mm but I felt everybody wouldn't understand so I listed it off.
3/ but my font size only goes up to 72 ?.... just type the font size into the box
4/ My characters are smaller when I print them out?......Have you selected bold like you were told too. If that doesn’t work then experiment for your computer/printer combo.
5/ I did your test and thought I had perfect sight, so I drove my car and crashed it killing my wheelchair bound grandmother. Can I sue you?....Read the disclaimer idiot, and don't dry you cat in the microwave.


[This message has been edited by Bomber Harris (edited 24 December 2000).]

[Island Air]

Do not want to p!ss on your parade Bomber, but a cosha chart can be bought for a couple of quid from a medical supplies company. If anyone wants to know where to find such a company, check near a uni medical school.

[QNH 1013]

Great idea bomber!

Island Air please remember that every couple of quid counts for some of us. Also, bomber's chart can be produced quickly at home over the Christmas Hols.

I made similar charts up a few years ago (using Word Perfect so details slightly different) and they have proved extremely useful.

Some extra important information:

Visual acuity increases considerably with illumination of the chart up to about 500 Lux (lumens per square metre) and this is fairly bright. As a guide, two 60 watt brand-new light bulbs about 1/3 metre in front of the chart would achieve about 500 lux. The direct glare from the bulbs must obviously be screened from the observer for the measurement of acuity. Alternatively, a single 100 watt reflector bulb (new) about 1 1/2 metre away will produce similar illumination.

The illumination is supposed to be even and without specular reflections.

My experience of eyesight standard tests is that the siting of the chart and the illumination is often very substandard. In my opinion, the medics often don't understand much about the importance of maintaining an illumination of at least 500 lux before trying to measure acuity.

I have been asked to read a test chart by a UK AME which was not illuminated except by ambient room lighting! He did not seem to be aware of the illumination standard required and eventually pointed an anglepoise light at the chart, after which I passed. Don't accept defeat unless the chart is correctly illuminated.

If anyone is interested (or cares) the standard for an internally illuminated chart is a luminance of 140 candela per square metre.

Happy Christmas to all