At the moment, several online refraction methods are available. However, these methods are not scientifically validated, unavailable outside the United States of America (USA) or not designed for customers. One of these online refraction methods is Opternative (Opternative (2017)). Opternative is currently used in the USA and is still developing (Opternative (2017)). It's a self-directed online refraction method using a computer-based response to presented stimuli with the use of a smartphone and a computer. Another method is EyeNetra (EyeNetra (2017) & Ohlendorf, Leube & Wahl (2016)). The use of this method is limited due to the need of special equipment such as a portable autorefractor, an autolensometer and a phoropter. Therefore, EyeNetra is mainly designed for optometrists and ophthalmologists for low-income populations. The same applies to SVOne; this method uses a Hartmann-Shack wavefront aberrometer which the user can attach to a smartphone (Ohlendorf, Leube & Wahl (2016)). Other online refraction methods are 6over6, but this method has not been released yet (6over6, (2017)), and Warby Parker (Warby Parker, (2017)).