Abstract
Purpose :
Myopia is one of the most common eye disorders worldwide and its prevalence is increasing both in children and adolescents. Therefore, controlling myopia progression is an urgent public health goal. We evaluated the effect of atropine by intravitreal (IVT) injection or topical instillation on lens-induced myopia in chicks.
Methods :
Right eyes of white leghorn chicks, aged five days, were covered with -9D spectacle lenses for 6 days. Chick received either IVT injections of atropine or saline on days 0, 2 and 4, or topical instillations of atropine once daily during the period. The refractive error and the axial length of the eyes were measured immediately prior to and 6 days after the lens was applied. After sacrifice, eyes underwent pathological analyses. For pharmacokinetics study 10% atropine (eye drops) or 1mM and10 mM atropine (IVT injections) was administered into right eyes, and both eyes were collected per animal at specified time points.
Results :
Lens coverage of eyes resulted in myopic changes in refractive error and axial length elongation. IVT injections of 100 mM atropine significantly inhibited both of axial length elongation and refractive error. However, topical instillation of 10% atropine was ineffective with respect to the myopic shift. The scleral concentrations of atropine following topical instillation were lower than those from the IVT injections. Histological analysis indicated differences in anatomical structure between birds and mammals.
Conclusions :
Atropine demonstrated anti-myopic effects via IVT injection, but not by topical instillation in this myopia model. The difference in efficacy between IVT injection and topical instillation might be due to anatomical features of the avian model, and the distribution of atropine to target tissues.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.