This is a 2-year, prospective, randomised, paired-eye controlled trial with cross-over which will be conducted at Ulster University, Coleraine, Northern Ireland. The trial will evaluate the efficacy of Essilor Stellest myopia management spectacle lenses on the progression of myopia in adults aged between 18-40 years. Participants will act as their own control, wearing a Stellest lens in front of one eye and a single vision lens in front of the fellow eye. At the 12-month visit, lens allocation will be crossed-over between eyes and worn for a further 12 months. Randomisation of whether Stellest will be worn in the dominant or non-dominant eye first will be conducted using permuted block design.
Participants will be asked to wear the study spectacles for at least 12 hours per day, 6 days per week. No other form of myopia management spectacle or contact lens will be worn during the trial period. At the two-year review participants will be given the option of continuing with Stellest lenses in both eyes or reverting to single vision spectacles in both eyes depending on the results of the study. Those participants who continue to wear Stellest lenses (binocularly) will be contacted after one month to investigate the acceptability of Stellest wear in adult myopes.
Participants will be screened at baseline to ensure they meet the inclusion criteria. Participants will be asked if they have ever attended the hospital eye service or have been told they have an eye condition by their optometrists. Fundus images and slit lamp examination will also be conducted at baseline to confirm eye health. Cycloplegic refraction and axial length will be measured at baseline, 6-months and 12-months using the Shin-Nippon NVision-K 5001 and IOLMaster 700 respectively. Cycloplegia will be induced by two drops of 1% tropicamide separated by 5 minutes. Punctal occlusion following instillation of the drop will be applied to reduce systemic absorption.
At 12-months, the crossover will take place. A further assessment of cycloplegic refraction and axial length will be performed 6-months (18-month visit) and 12-months (24-month visit) after the crossover. The following additional measurements will also be made to inform parameters that are associated with better response to treatment and to ensure visual function remains adequate while wearing the study spectacles. These measurements will be taken at baseline and crossover.
* Near and distance visual acuity will be measured using a crowded logMAR letter chart at 33cm and 3m
* Accommodative function will be assessed using dynamic retinoscopy using the UC-Cube
* Binocularity will be assessed using distance and near prism cover test
* Field of vision will be assessed using a Humphrey suprathreshold screening test
* Peripheral refraction will be measured at 30 degrees nasally and temporally
* Choroidal thickness will be measured using a six radial scan using the Heidelberg Spectralis
* Visual comfort will be surveyed by telephone one week after collection of the study spectacles to ensure participants are tolerating the paired-eye control condition
