通信モード使えない
のせいか、ios9.2の今は、
通信モードで使えない。
追記、その後バージョンアップされて
iOS 10.3でも、使えています。
ipadで表示させてiPhoneで操作と確認できるので一人で視力テストが出来るので正規のテストに近い状況で自分の視力がほぼ自覚出来て便利です。

Perform eye tests using your iPhone or iPad. Features single-device testing with adjustable charts and a two-device 'Connect mode' for remote operation. Ideal for quick vision checks at home.
1.4
December 2, 2022
Fixed minor bugs.
EyeTesterPro is a mobile application designed to facilitate eye tests. It offers both single-device and dual-device testing modes, allowing users to check their vision with adjustable charts and remote control capabilities.
In 'Connect mode', two iPhones or iPads can communicate via Bluetooth. One device acts as the remote control to select distance, answer, and view results, while the other displays the eye test chart.
No, EyeTesterPro explicitly states it does not guarantee eye test results. For accurate diagnosis, users should consult an ophthalmologist.
EyeTesterPro is supported on iPhone, iPad, and iPod devices. It requires at least one iPad to test at a distance of five meters.
EyeTesterPro is a paid application priced at $40.99. There are no in-app purchases or subscriptions mentioned.
The latest version of EyeTesterPro is 1.4, last updated on December 2, 2022. The app was originally released on March 22, 2011.
EyeTesterPro has an age rating of 4+, making it suitable for a wide range of users. It is developed by FUSO PRECISION.
No, EyeTesterPro does not contain advertisements. The application is a one-time purchase with no ads or in-app purchases.