A trial to assess the retinal function of the eye when using a novel contact lens for myopia management

This is a prospective, randomised, contralateral clinical trial. All participants will wear one test and one control contact lens simultaneously. The eye in which each the test and control is worn will be randomly determined. All contact lenses are made from a commercially available HEMA material (55% water) and are single use. The test will be a single vision contact lens with a tinted edge pattern and the control will be single vision contact lens with no tinted edge pattern. This study will recruit emmetropic and myopic participants. Emmetropic participants will wear plano power contact lenses and myopic participants will wear powered contact to correct their myopia. Participants will attend one single visit. The study will comprise one visit with a total duration of approximately 80 minutes. All measurements will be performed by an optometrist. The initial measurements are performed prior to contact lens insertion, and comprise the photopic negative response (PhNR), pattern electroretinogram (PERG), and axial length. Contact lenses will be inserted after these measurements are taken. Participants will wear contact lenses and watch a greyscale television at 4 m in a room with an illumination of 700 lux for 10 minutes, after which the PhNR will be measured while wearing contact lenses. Participants will continue wearing contact lenses and watch a greyscale television at 4 m in a room with an illumination of 700 lux for a further 40 minutes, after which the PhNR and PERG will then be measured while wearing contact lenses. Adherence to watching the greyscale television will be monitored by research staff. Contact lenses will be removed, and the axial length will be measured.