title: SCLERAL AND CHOROIDAL THICKNESS IN SECONDARY HIGH AXIAL MYOPIA.
abstract: OBJECTIVE
  To assess differences in scleral and choroidal thickness between eyes with secondary high axial myopia caused by congenital glaucoma, eyes with primary high axial myopia, and nonhighly myopic eyes.
  
  
  METHODS
  The study consisted of 301 Chinese individuals with a mean age of 23.9 ± 22.6 years and mean axial length of 24.8 ± 4.2 mm. It included the "secondary highly myopic group" (SHMG) because of congenital glaucoma (n = 20 eyes; axial length >26.0 mm), the "primary highly myopic group" (PHMG) (n = 73; axial length >26.0 mm), and the remaining nonhighly myopic group (NHMG).
  
  
  RESULTS
  The secondary highly myopic group versus the primary highly myopic group had significantly thinner sclera in the pars plana region (343 ± 71 μm versus 398 ± 83 μm; P = 0.006), whereas scleral thickness in other regions did not differ significantly between both highly myopic groups and was significantly thinner in both highly myopic groups than in the NHMG. Mean total scleral volume did not differ significantly (P > 0.20) between any group (SHMG: 659 ± 106 μm; PHMG: 667 ± 128 μm; NHMG: 626 ± 135 μm). Choroidal thickness was significantly thinner in both highly myopic groups than in the NHMG, with no significant differences between both highly myopic groups. Choroidal volume did not differ significantly (P > 0.40) between any of the groups (SHMG: 43 ± 12 μm; PHMG: 43 ± 13 μm; NHMG: 46 ± 17 μm).
  
  
  CONCLUSIONS
  In secondary high axial myopia, the sclera gets thinner anterior and posterior to the equator; whereas in primary high axial myopia, scleral thinning is predominantly found posterior to the equator. Because volume of sclera and choroid did not differ between any group, scleral and choroidal thinning in myopia may be due to a rearrangement of tissue and not due to the new formation of tissue.
authors.affiliation: *Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China; †Department of Ophthalmology, The 2nd Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China; and ‡Department of Ophthalmology, Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg, Mannheim, Germany.
authors.forename: Ling
authors.initials: L
authors.lastname: Shen
authors.forename: Qi Sheng
authors.initials: QS
authors.lastname: You
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Xu
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Zhibao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002829:Choroid / Q000473:pathology*; D015353:Eye Enucleation; D005260:Female; D006801:Humans; D006871:Hydrophthalmos / Q000150:complications* / Q000601:surgery; D007223:Infant; D008297:Male; D008545:Melanoma / Q000150:complications* / Q000601:surgery; D008875:Middle Aged; D047728:Myopia, Degenerative / Q000209:etiology*; D009929:Organ Size; D019572:Retinal Neoplasms / Q000150:complications* / Q000601:surgery; D012175:Retinoblastoma / Q000150:complications* / Q000601:surgery; D012590:Sclera / Q000473:pathology*; D014604:Uveal Neoplasms / Q000150:complications* / Q000601:surgery; D055815:Young Adult; D000098943:Uveal Melanoma