Focus-out Glasses on Emmetropization in Chinese Children

Effect of Peripheral Focus-out Glasses on Emmetropization in Chinese Children Aged 6-8 Years: 2 Years Randomized Clinical Trial.

The purpose of this study is to characterize the effects of peripheral focous-out glasses on emmetropization in non-myopic Chinese Children Aged 6-8 Years.This is a prospective, parallel-controlled randomized trial.

Myopia is one of the most common eye diseases that cause visual impairment and blindness, and the high rate of myopia in young people is a major public health issue. Based on the clinical studies of optical defocusing to regulate eye growth and refractive changes through visual signal feedback, we hypothesize that early wearing of peripheral defocus glasses in children can slow down the process of emmetropization and even prevent the onset of myopia by producing more myopic defocusing. The aim of this study is to investigate whether wearing peripheral defocus glasses can effectively delay emmetropization in non-myopic children aged 6-8 years , and to further explore its effect on preventing the onset of myopia. The study adopts a 2-year，single-centre, randomized, parallel-controlled trial with a non-blinded design. Subjects who pass the screening period will have their baseline data collected and will be assigned to the experimental or control groups according to the randomization principle. The experimental group will be fitted with Direct Emmetropia with Focus-out Glasses (hereafter referred to as DEFOG) to guide the emmetropization process. The control group will be given no treatment and will be a blank control. Baseline data including visual acuity, cycloplegic objective refraction, axis length, accommodation amplitude, strabismus examination, pupil size, choroidal thickness and peripheral retinal refraction will be measured when enrolled in the group and follow-up data will be measured at month 6, 12, 18 and 24. The primary interest of this study will be studied by comparing the difference in cycloplegic objective refraction changes between month 24 and baseline in the two groups of subjects.

Subjects in the intervention group will wear peripheral focus-out glasses ≧8 hours a day and ≧5 days a week.

Changes of cycloplegic objective refraction(i.e reflected by SER) from baseline till the 24th month (only the right-eye data included). Objective refraction data will be examined by AUTO REF/KERATOMETER. Ciliary muscle paralysis will be performed by using 1% cyclopentanone eye drops, 2 doses in each eye, 2 doses 5 minutes apart. The optometry will be performed after 20 minutes of complete ciliary muscle paralysis (disappearance of pupil response to light or pupil diameter at least greater than 6 mm). SER is calculated by adding the sum of the sphere power with half of the cylinder power. Baseline data will be measured at the time of enrollment. Follow-up data will be measured on the 24th month from baseline. The 24th month data will be subtracted from the baseline data to obtain changes.

Changes of cycloplegic objective refraction (i.e reflected by SER) different follow-up time and the baseline time (only the right-eye data included). Objective refraction data will be examined by AUTO REF/KERATOMETER.

Cycloplegic objective refraction (i.e reflected by SER) any follow-up time (only the right-eye data included). Objective refraction data will be examined by AUTO REF/KERATOMETER.

Cycloplegic SER≦-0.50D at any follow-up time. Objective refraction data will be examined by AUTO REF/KERATOMETER.

Changes of Axial Length (AL) between different follow-up time and the baseline time (only the right-eye data included).AL will be examined by IOL Master.

Axial Length (AL) at any follow-up time (only the right-eye data included).AL will be examined by IOL Master.

Amplitude of Accommodation (AMP) at any follow-up time (only the right-eye data included). AMP will be examined by lens test.

Changes of Choroidal Thickness (ChT)between different follow-up time and the baseline time (only the right-eye data included). ChT will be examined by OPTICALCOHERENCETOMOGRAPHY.

Peripheral Retinal Refraction at any follow-up time (only the right-eye data included). Peripheral Retinal Refraction will be examined by AUTO FUNDUS CAMERA.

Inclusion Criteria: Age: ≥6 and ≤8 years at enrollment. At least one parent' s Spherical equivalent refraction≤-3.00D. Spherical equivalent refractions (SERs) under cycloplegia: +0.50 to +1.50 diopters (D) Astigmatism ≤1.00 D . Anisometropia ≤1.00 D. Best Corrected Visual Acuity (BCVA) : 1.0 or better Provision of consent written by subject's legal guardian Willing and able to participate in all required activities of the study Exclusion Criteria: Any of the following abnormalities on the ocular surface, such as trachoma, pemphigoid, chemical injury, heat burn, radiation injury, etc. Eyelid abnormalities (e.g. entropion, ectropion, tumor, edema, blepharospasm, incomplete eyelid closure, severe trichiasis, severe ptosis) ,which affect eyelid function in either eye Eye diseases such as strabismus, amblyopia, anisometropia, fundus diseases, and accommodation abnormality，etc. Prior treatment of myopia control in either eye, including but not limited to drugs, orthokeratology, low-level red-light therapy, etc. Noncompliance with measurement at enrollment.