App Review: iSight Test by Kay pictures

Once in a while there comes along an app which sounds like it should be essential purchase. The official Kay pictures chart app is now available on the iOS App Store. It's clearly aimed at both the home/non-professional market and the optometric market alike, so does it still hold up to the physical charts? Was it worth the wait? 

Find out after the break in this weeks app review.
Once you find and install the surprisingly small 2.4MB universal app you're straight in to the mode selection screen. There is a notice to turn the brightness down to 50% and turn off auto-brightness. I can only assume this is to keep the brightness similar to a paper chart...or to save the battery life of your iOS device, which is surprisingly well maintained for an app with a predominantly white background.

Main menu
The user interface is a clean and tidy offering, with easily navigated sections clearly laid out. There is a fantastic option to record the results in the app, making keeping track of the LogMar scores a breeze. When performing a test with the save mode activated you can create usernames meaning your record system on the app and on your clinic database can be synchronised. From a home user perspective the save system allows a parent to keep track of multiple children's visual acuities and monitor them over time.

A full gamut of chart types are included. Adult and paediatric distance test types are available for all iOS devices, near types are only included for iPad and retina display iPhones. These are labelled Letter and Children's picture test; clearly a concession to the home-market but one that makes little difference to the professional user.

After clicking on the test type required a few expected options are made available, such as eye(s) being tested, testing distance and if you wish to record the results or not. One excellent feature in the picture tests (for both under and over 3's) is the ability to check recognition and practice naming without entering the test "cold".

The distance tests are designed to be used at 3m. The clarity of the optotypes is excellent, with crisp images being delivered for the full range of sizes on both the iPad and the iPhone. There is slight concession to the smaller screen size of the iPhone in that crowding bars are only introduced around single optotypes at 0.4 and a full bar of optotypes only being used from 0.2 onwards, the iPad version does not have this issue. Whilst this doesn't ruin the testing strategy it does act as a cap on usefulness in a clinical setting.

Near vision testing
Near vision testing is a dream in both modes. For the letter testing the standard near vision font is used and the letter size clearly displayed in standard 'N' format. Letter reproduction is crystal clear, even at N5 and its obvious that limiting this mode to retina screens on the iPhone was a wise decision. For the picture tests, crowding bars are used throughout for the over three age group and single uncrowded optotypes for the under threes. The results are displayed in log as you would expect from a Kay test and once again picture quality is superb on all devices that allow this mode.

The rotate screen prompt.
One limitation of allowing the distance charts to be used on an iPhone at all is the issue of screen rotation. In order to accommodate the larger optotype size the screen must be rotated. Whilst this is prompted during the testing strategy it acts to break up the fluidity felt when using the app on the iPad, or even when comparing it to using the 3m physical flip charts. Furthermore when using for domiciliary visits the necessity to rotate the screen did confuse matters with some of the patients as they felt the test had ended when I picked up the device to rotate it.

The choice of testing strategy is also affected by the need to allow for the home user market. A seeming mishmash of distance test charts is used unlike in the app's physical older siblings, which present a coherent strategy throughout. The test slowly ramps up from single uncrowded to single crowded before finishing up on crowded multiple optotypes. However it should be noted that for the under threes the traditional single optotype method is maintained and testing is much more fluid as a result.

In an attempt to become more mass-market Kay pictures have tried to simplify the vision testing for concerned parents, mothers groups and other non-optical professionals. Whilst spreading the eduction of the need for eye exams is absolutely laudible, from a technical design perspective obvious compromises have had to be made; such as the combining of test strategies mentioned above and removing the option to freely turn on and off crowding. Given the presumptive aim of getting more childrens sight tested, the disclaimer about "Testing eyesight is only one part of a full eye examination..." is too well hidden in the information section under a subsection of disclaimer and should rather be included in both the appstore description and as a splash screen when starting the app.

From an optometric stand point I would have rather had a purely digital version of the physical charts aimed squarely at the professional market. This could have included more coherent testing strategies as no compromises would need to be made. In addition the option to freely turn on and off the crowding bars is sorely missed.

As a final statement I would only fully recommend the iSight app for those with an iPad, the distance vision testing experience on the iPhone is just simply not fluid due to the screen rotation issues mentioned above. If you are a particularly keen user of an iPhone and don't want to spend on an iPad then it is usable, but not ideal. However, it is a universal app, so once purchased on one device you can use it across all your iOS devices without having to purchase another license.

Overall compromises have been made and it's not the complete digital test chart one would have hoped Kay's could release, but at the price point of £7.49/$12.99 it's still well worth getting.

iSight Test is available now on the iTunes App Store.

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