Rick1407,
EK use the CAD test, it is also becoming the standard colour vision assessment amongst other aviation authorities like EASA.
It is basically a 'blob' of large pixels moving towards the edge of the screen against a background of other alternating large pixels. You have a keypad to indicate where the 'blob' leaves the screen. The test repeats every couple of seconds. The system alternates the colour spectrums to to test red/green yellow/blue vision. To find your 'level' of deficiency you won't be able to see the 'blob' for approximately half the tests. You get a nice graph at the end that shows exactly how your colour vision performs.
I did the lantern test for my initial CAA medical, I did the CAD test at a University in London who designed the test for the CAA (EASA). You can see on youtube approximately what it is like, however the actual test is done with a carefully calibrated screen. As part of the Universities research I also did all the other available colour tests, the Ishihara is the only one I can't pass fully.
Once you have done the CAD test with EK you don't have to do it again. Your medical will be endorsed 'Colour Safe' in the limitations. As has been said before EK seem to still love giving you the Ishihara test every year even though you tell them you can't do it!!
Good luck.