Part-time Versus Full-time Spectacles for Myopia Control (ParMA Study)

A prospective, randomized, controlled clinical trial was designed for assessing the effect of single-vision spectacles on myopic progression. 30 myopic subjects, aged 6-16 years old, with a spherical equivalent refraction between -0.50D and -6.00D, were recruited. A random number table was used to allocate participants into either a) part-time use of single-vision spectacles, or b) full-time use of single-vision spectacles. Part-time use was for 4-6 hours a day, 7 days a week for a year. Clinical assessment included follow-up at 6 months and at 12 months upon allocation. The primary outcomes were a) change in spherical equivalent refraction (SER) measured by cycloplegic autorefraction, and b) change in axial eye length (AL). The secondary outcomes were a) change in choroidal thickness (ChT), and b) assessment of the subjective tolerance.

Inclusion criteria

• Age 4 to 16 years old at the time of enrollment.
• Best-corrected visual acuity (BCVA) LogMAR 0.1 or better, in each eye.
• Cycloplegic Autorefraction: Myopia, SER between -0.50D and -6.00D, in each eye. Astigmatism less than or equal to 1.50D, in each eye. Anisometropia less than or equal to 1.50D between the two eyes.
• Absence of any ocular or systemic condition that could influence refractive development, other than myopia.
• Eagerness to participate in this study and receive myopia treatment in a randomized fashion. Availability for at least 1-year follow-up. Subject parent's or guardian's understanding of the protocol and acceptance to participate, providing a signed consent on behalf of the subject.

Exclusion criteria

• Presence of strabismus.
• Presence of amblyopia.
• Prematurity (gestational age less than 37 weeks).
• Presence of an ocular condition affecting refraction (ie. cataract, dislocated lens).
• Presence of a systemic condition affecting refraction (ie. Down syndrome, Marfan syndrome).
• Allergy to cyclopentolate. Severe ocular or systemic allergies.