So, just how good is the resolution on your new iPhone? Well, here’s your chance to find out … with a portable eye chart! The incredibly high resolution of the iPhone’s LCD screen makes it an excellent tool for checking vision! On this page you’ll find an eye chart that you can “install” on your new phone.
Some advantages to this chart:
1. Patient isn’t confused about “which line to read.”
2. Backlighting forgoes need for flashlight and helps with pinhole pam
3. The phone is harder to loose than a near card
4. This is another good excuse to buy that iPhone
I’ve calibrated the letter sizes directly from a Rosenbaum screening card. You can see the Snellen and Jaeger acuity in the bottom right corner of every photo. The resolution of the ipod screen limits the best near acuity to about 20/25, which is still pretty impressive! See it in action with this movie:
To download these pictures, right-mouse click on each of the photos below (go in order) and choose “save target as …” to download them onto your computer. Then, import them onto your iphone and view then through your image browser!
A near card like this is normally held at about 14 inches from the eyes … a 90 degree bend at your elbow should be sufficient.
Cool idea, but pixel size limits VA testing at near distances: cannot accurately test 20/20!
But again, very cool idea! It will be interesting to use when screen resolution improves.
Actually, you should drop the 20/xx labelling which has no place in near testing anyway, and Jaeger is ridiculous (just try to find any system to the sizes. Simply increase the viewing distance appropriately, the resolution does not have to be a problem. I recommend using M notation or as a second best, point notation (which has similarities at smaller sizes ie .6M=6 point .8M=8point) At 40cm (16 inches) .4M or 4 point = theoretical 20/20 which is beyond resolution of iPhone. All you have to do is use .8M or 8 point print at 80cm to measure the same thing. Fortunatly, almost none of our patients need to read 4 point print anyway.
Comment by Bill OConnell — June 30, 2008 @ 10:07 am
P.S. - Nice application though. Add in random letter generation (keeping letter combinations of equal difficulty), single words, and continuouos text and you have a real winner!
Definitely makes an iPhone tax deductable!!!
Comment by Bill OConnell — June 30, 2008 @ 10:10 am
So, just how good is the resolution on your new iPhone? Well, here’s your chance to find out … with a portable eye chart! The incredibly high resolution of the iPhone’s LCD screen makes it an excellent tool for checking vision! On this page you’ll find an eye chart that you can “install” on your new phone. 
