A Controlled Evaluation of Optical Defocus Parameters on Transient Changes in Axial Length Using Kubota Glass

This study will assess the optimal performance characteristics of optical defocus on transient changes in axial length with Kubota Glass, using a randomized, double-masked, 5-treatment, 5-period crossover design with contralateral eye control.

Inclusion Criteria: * Be of legal age or, if under legal age have written consent of their parent or guardian to participate. * Sign written Informed Consent (and the California Bill of Rights, if applicable). * Be between age 8-24 (inclusive) and able to understand and assent to participation. * Have a spherical component of spectacle prescription between -1.00 and -5.00 diopters (D) (inclusive) in each eye. * Have a refractive astigmatism of less than or equal to -1.00 D in each eye. * Have axial length between 23.00 and 25.99 millimeters (mm) in each eye. * Best Spectacle Corrected Visual Acuity (BSCVA) of 20/25 or better in each eye. * Be willing and able to follow instructions and attend the schedule of follow-up visits. Exclusion Criteria: * Unable or unwilling to provide informed consent and assent. * Eye injury or surgery within twelve weeks immediately prior to enrollment. * Currently enrolled in an ophthalmic clinical trial. * Pregnant or lactating or expect to become pregnant during the trial (by self-report). * Evidence of systemic or ocular abnormality, infection or disease. * Use of medications that may affect the eye (including, but not limited to, corticosteroids and antimetabolites). * Anisometropia ≥ 2.00. * Subjects who have undergone corneal refractive surgery. * Use atropine or other anticholinergic drug within the past month. * Employees or immediate family members of employees of study sites or sponsor.