title: Recovery from axial myopia induced by a monocularly deprived facemask in adolescent (7-week-old) guinea pigs.
abstract: OBJECTIVE
  Guinea pigs have been increasingly used as an animal model for experimental myopia. Infant guinea pigs are susceptible to recovery from myopia within 2 weeks of form deprivation. This study investigated whether adolescent guinea pigs are susceptible to recovery from myopia after a longer period of form deprivation.
  
  
  METHODS
  Twenty-two guinea pigs (age of 3 weeks) were randomly assigned to two groups: MDF (monocularly deprived facemask, n=11) and normal control (free of form deprivation, n=11). All animals underwent biometric measurement (refraction, corneal curvature and axial length) prior to the experiment. Animals in the MDF group wore a facemask that covered the right eye for 4 weeks. The MDF was then removed and biometric measurement was performed immediately and at 2, 6, 10 and 14 days. The same measurement was performed in the normal control group at time-points matching those of the MDF group.
  
  
  RESULTS
  The MDF eyes were approximately 4D more myopic with a greater increase in vitreous length by 0.12 mm compared to either the fellow or the normal control eyes after form deprivation (p<0.01). This relative myopia shifted rapidly towards hyperopia within 2 days after removal of the MDF, followed by a more gradual recovery. A complete recovery occurred by 6 days after removal of the MDF compared to the fellow and normal control eyes (p>0.05). Vitreous length in the MDF eyes slightly reduced within 2 days after removal of the MDF and then remained steady. The MDF eyes were similar to both the fellow and normal control eyes in vitreous length (p>0.05) 6 days after removal of the MDF. There was no significant difference between the MDF, fellow and normal control eyes in the other axial components during the form deprivation and recovery period.
  
  
  CONCLUSIONS
  Adolescent guinea pigs are susceptible to recovery from MDF-induced myopia. The refractive recovery is mainly correlated to the inhibited axial elongation of the vitreous chamber of the previously deprived eyes.
authors.affiliation: School of Optometry and Ophthalmology, Eye Hospital, Wenzhou Medical College, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China.
authors.forename: Xiangtian
authors.initials: X
authors.lastname: Zhou
authors.forename: Fan
authors.initials: F
authors.lastname: Lu
authors.forename: Ruozhong
authors.initials: R
authors.lastname: Xie
authors.forename: Liqin
authors.initials: L
authors.lastname: Jiang
authors.forename: Jiquan
authors.initials: J
authors.lastname: Wen
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Jianzhen
authors.initials: J
authors.lastname: Shi
authors.forename: Tian
authors.initials: T
authors.lastname: He
authors.forename: Jia
authors.initials: J
authors.lastname: Qu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003315:Cornea / Q000473:pathology; D006168:Guinea Pigs; D023421:Models, Animal; D009216:Myopia / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D011897:Random Allocation; D012030:Refractive Errors; D012683:Sensory Deprivation; D013997:Time Factors; D015349:Vision, Monocular; D014822:Vitreous Body / Q000473:pathology