Brimonidine as a possible treatment for myopia

Background Myopia is becoming a huge burden on the world’s public health systems. The purpose of this study was to explore the effect of brimonidine in the treatment of form-deprivation myopia (FDM) and the relationship between intraocular pressure (IOP) and myopia development. Methods Monocular form deprivation myopia (FDM) was induced in three-week-old pigmented male guinea pigs. They were treated with 3 different methods of brimonidine administration (eye drops, and subconjunctival or intravitreal injections). Four different concentrations of brimonidine were tested for each method (2 µ g/ µ L, 4 µ g/ µ L, 20 µ g/ µ L, and 40 µ g/ µ L). All treatments continued for a period of 21 days. Tonometry, retinoscopy, and A-scan ultrasonography were used to monitor intraocular pressure, refractive error and axial length (AL), respectively. Results Treatment with subconjunctival brimonidine at 40 µ g/ µ L, and intravitreal brimonidine at 2 µ g/ µ L and 4 µ g/ µ L, inhibited the development of FDM. The myopic refraction, excessive axial length, and elevation of IOP were significantly decreased. Brimonidine in eye drops was ineffective. Conclusion Brimonidine at appropriate doses significantly reduced the development of FD myopia in guinea pigs. The IOP may change with FD myopia.