How often do we need an eyesight test?

Thank you for your question! According to the American Academy of Ophthalmology, "Individuals who do not have symptoms but who are at high risk of developing ocular abnormalities related to systemic diseases, such as diabetes mellitus and hypertension or who have a family history of eye disease, require periodic comprehensive eye examinations to prevent or minimize visual loss". More information can be found here: http://www.aao.org/clinical-statement/frequency-of-ocular-examinations--november-2009