title: [High myopia and retinal ultrastructure of albino guinea-pigs].
abstract: OBJECTIVE
  To explore the relationship between melanin synthesis and the congenital high myopia of albino guinea-pigs.
  
  
  METHODS
  Twelve albino guinea-pigs and 12 pigmented guinea-pigs of 220~250 grams (aged 5~6 weeks) were chosen at random. The eyes were examined with retinoscopy, A-scan ultrasonography and vernier caliper. The retinal structures were examined with light and electronic microscope.
  
  
  RESULTS
  The diopter was -19.17 D in albino guinea-pigs and +0.63 D in pigmented guinea-pigs on average. Compared with the pigmented guinea-pigs, the axial dimensions of the albino guinea-pigs were elongated. There was significant difference between the albino guinea-pigs and the pigmented guinea-pigs. The retinal thickness, pigment granules and membrane disc of the outer segment of the visual cells decreased in the albino guinea-pigs, and the membrane disc space became narrow. The normal retinal thickness, plenty of pigment granules , membrane disc and wide membrane disc space could be observed in the pigmented guinea-pigs.
  
  
  CONCLUSIONS
  Albino guinea-pigs have high myopia, and pigmented guinea pigs have light hyperopia. There are structural differences in the retina between albino guinea-pigs and pigmented guinea-pigs. The abnormity of albino guinea-pigs provides optical foundation for its high myopia.
authors.affiliation: Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China.
authors.forename: Jie-Yue
authors.initials: JY
authors.lastname: Wang
authors.forename: Shuang-Zhen
authors.initials: SZ
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Wei
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Wu
authors.forename: Xing-Ping
authors.initials: XP
authors.lastname: Tan
mesh_terms: D000417:Albinism / Q000150:complications*; D000818:Animals; D006168:Guinea Pigs; D008543:Melanins / Q000096:biosynthesis*; D008855:Microscopy, Electron, Scanning; D009216:Myopia / Q000151:congenital / Q000209:etiology / Q000378:metabolism*; D011897:Random Allocation; D012160:Retina / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D012880:Skin Pigmentation
chemical_list: D008543:Melanins