Online eye tests have grown in popularity, but it is important to understand their limitations. While digital tools can provide a rough indication of your visual acuity, they cannot replace a comprehensive in-person eye examination carried out by a qualified optometrist.
Online vision screening tools typically test how well you can read letters or shapes on your screen from a set distance. Some more advanced services use your smartphone camera and algorithms to estimate your glasses prescription. These can be useful as a quick check — for example, if you are wondering whether your vision has changed since your last test — but they have significant limitations. They cannot measure eye pressure (critical for glaucoma screening), examine the health of the retina and optic nerve, detect conditions like cataracts or macular degeneration, or assess your binocular vision (how your eyes work together).
In the UK, a valid glasses prescription can only be issued by a registered optometrist or ophthalmic medical practitioner following an in-person sight test. Online tools cannot legally provide a prescription, and no reputable UK optician will dispense glasses based solely on an online test result. The General Optical Council (GOC), which regulates the optical profession in the UK, has been clear that online tests do not meet the clinical standards required for a sight test.
That said, some legitimate services offer remote consultations where an optometrist reviews your results and provides guidance via video call. These are more credible than fully automated tools but still cannot replace the physical examination of your eyes. They may be useful for follow-up consultations or advice between in-person tests.
The best approach is to use online tools as a rough check and conversation starter, but always book a proper in-person eye test for your definitive assessment. With eye tests costing as little as £20 to £25 (or free if you qualify for an NHS test), the cost of an in-person test is minimal compared to the value of a thorough examination.