According to Rono, the adapter-with-app combo is 50 times cheaper than traditional eye-testing equipment, and can be operated by community members rather than just health workers. And so far it’s proven just as effective.

A study based on 300 adults in central Kenya published last year in the journal JAMA Ophthalmology found Peek’s vision test app was as accurate as a paper chart exam (or electronic methods) used at a health clinic. Another study in the journal, released in February, found “no observable difference” between the quality of images taken with Peek’s equipment than that of a digital retinal camera used by an ophthalmic assistant.

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