Sydney-based optometrist Jonathan Sykes has developed a free eyechart app with the goal of eradicating the use of numbers as an optotype in countries with non-Latin scripts. WolfChart acts as a professional tool for measuring visual acuity and performing other distance refraction tests, can work in any browser and can be set up to use the native script of the patients it serves.
“The light really came on when a colleague in Israel told me he uses numbers because there are no Hebrew eye charts,” Dr Sykes told mivision. “Numbers are a terrible optotype for accuracy and repeatability. They vary wildly in readability, and there are only 10 of them, so it’s easy to guess correctly.
“So I dove right in and built a 15-letter Hebrew optotype using about 40 lines of simple code. From there, it was just a matter of building a fully-featured chart that any practitioner can use, and to which I can easily add any symbols you might need for your patients.”
WolfChart features Landolt C, Tumbling E and Vanishing Sloan as well as the standard Snellen and Sloan options. It also allows practitioners to record in fractional, DecimalV or logMAR notation and configure for viewing distance, mirrored or not.
“With this flexibility, WolfChart also works well in domiciliary and research settings, in fact it’s already in use in The George Institute’s research on falls prevention,” said Dr Sykes.
To get started, all you need is a computer and screen and the measurements of your room. This ease of use not only avoids the costs associated with a proprietary chart, it also minimises the amount of devices needed in the consulting room.
Dr Sykes says his next challenge is launching WolfChart in non-English speaking countries and those with potential roadblocks, such as government firewalls. He believes repackaging WolfChart as a tablet app, available via location specific app-stores, will likely progress this goal.