Background: There are some uncertainties about the effect of low-power red laser treatment on myopia control for anisometropic myopia in children. To evaluate the effect and safety of low-power red laser treatment on refractive development for anisometropic myopia in children, a contralateral comparison study was conducted.
Methods: The more myopic eye of child with anisometropic myopia was treated with low-power red laser treatment (LRL group), the other eye received no treatment other than the wearing of single-focus spectacles (SFS) (SFS Group). The LRL treatment was given at home under parental guidance for 3 minutes each time, twice daily with a minimal interval of 4 hours, 7 days per week, using an equipment that produces red laser of 650 nm wavelength at an illuminance range of roughly 1200-1800 lux and an energy of 0.60 mw for a 4-mm pupil (class I classification).
Results: Among 51 included children, 44 (86.27%) completed the 3-months study, consisting of 15 girls (34.1%) and 29 boys (65.9%). After 3-months axial length (AL) and spherical equivalent refraction (SER) progression were -0.08 mm [95% CI (confidence interval), 0.11 to 0.06 mm] and +0.23 diopter (D) (95% CI, 0.13-0.33 D) for LRL group and +0.08 mm (95% CI, 0.05-0.11 mm) and -0.07 D (95% CI, -0.16-0.03 D) for SFS group. AL and SER progression between the groups varied by 0.17 mm (95% CI, 0.13-0.20 mm) and -0.30 D (95% CI, -0.42 to -0.18 D). There was no visible structural damage on optical coherence tomography (OCT) scans.
Conclusions: AL growth, myopia progression, and anisometropia of the binoculars can all be slowed down by LRL treatment. Compared to SER progression, axial elongation is more accurate and simpler to monitor. LRL treatment unrecorded functional and structural damage of binoculus.
Keywords: anisometropic; axial length; contralateral comparison; low-power red laser treatment; myopia.