title: Effects of direct intravitreal dopamine injection on sclera and retina in form-deprived myopic rabbits.
abstract: OBJECTIVE
  The aim of this study was to investigate morphologic changes of retina and sclera in form-deprived myopic rabbits following intravitreal dopamine injection.
  
  
  METHODS
  Neonatal rabbits were monocularly deprived of form vision by suturing the right eyelids after natural eye opening. In the form deprivation (FD) group, the right eye received FD alone. In the dopamine-form deprivation (DA-FD) group, the deprived eye received an intravitreal injection of 20 microg of dopamine every 5 days for a total of 4 injections. In the saline-FD group, the deprived eye received saline injections to the same schedule as the DA-FD group. The untreated contralateral eyes were used as controls. After an 8-week treatment period, the effects of DA on sclera and retina anterior and posterior to the equator were evaluated by light and electron microscopy.
  
  
  RESULTS
  Treated eyes in the FD and saline-FD groups developed form deprivation myopia. These eyes had markedly reduced scleral thickness and smaller diameter scleral collagen fibrils posterior to the equator. In addition, the normal gradient of fibril size from the outer to the inner layers of the posterior sclera was absent in the treated eyes of both the FD and saline-FD groups. In contrast, posterior scleral thickness was greater in DA-FD eyes than in contralateral controls. A distinct swelling of retinal pigment epithelium mitochondria was observed in the treated eye of the DA-FD group, but no obvious retinal abnormalities were found in the treated eyes of the other two groups.
  
  
  CONCLUSIONS
  The sclera, especially posterior sclera, plays an important role in both the induction and inhibition of myopia. An additional finding was that changes in the sclera of rabbits with low myopia were similar to those of the sclera of other mammals with high myopia. The results of this study will contribute to the understanding of the mechanisms of myopia development and inhibition by intravitreal dopamine injection.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Lin
authors.forename: Xiang
authors.initials: X
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Ge
authors.forename: Domgmei
authors.initials: D
authors.lastname: Cui
authors.forename: Junshu
authors.initials: J
authors.lastname: Wu
authors.forename: Fuxing
authors.initials: F
authors.lastname: Tang
authors.forename: Juan
authors.initials: J
authors.lastname: Tan
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Zhong
authors.forename: Qianying
authors.initials: Q
authors.lastname: Gao
mesh_terms: D000818:Animals; D004298:Dopamine / Q000008:administration & dosage*; D007267:Injections; D046529:Microscopy, Electron, Transmission; D009216:Myopia / Q000188:drug therapy* / Q000473:pathology; D011817:Rabbits; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000473:pathology; D012590:Sclera / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D014822:Vitreous Body / Q000187:drug effects*
chemical_list: D004298:Dopamine