title: Analysis of Peripapillary Geometric Characters in High Myopia Using Swept-Source Optical Coherence Tomography.
abstract: OBJECTIVE
  We measured the three-dimensional geometric profile around the optic nerve head (ONH) using swept-source optical coherence tomography (SS-OCT) in highly myopic eyes.
  
  
  METHODS
  We studied 114 highly myopic eyes (<-6.0 diopters [D]) of 114 patients without glaucoma. Eyes were examined using the prototype SS-OCT. The retinal pigment epithelium (RPE) and chorioscleral interface were traced, and the mean y-axis coordinates of 24 sectors were calculated in circular peripapillary (3.4-mm diameter) images. The peripapillary tilting index (PTI) was calculated by subtracting the mean y-axis coordinate of the RPE in a sector from the mean of all sectors. The main outcome measures were the PTI and its association with the staphyloma depth from the OCT images and the ovality index (OI) of the ONH and peripapillary atrophy (PPA) area from fundus photographs.
  
  
  RESULTS
  The PTI differed significantly (P < 0.0001) among the 24 sectors and was lowest at the inferotemporal sector (-1930.76 μm). The minimal PTI value was in the temporal to inferotemporal sectors in 88 (77.2%) eyes and was correlated significantly with the OI (P < 0.0001) and age (P < 0.001) but not with the equivalent refractive error or axial length. The minimal PTI was correlated significantly with the PPA area (P < 0.05), minimal choroidal thickness (P < 0.05), macular choroidal thickness (P < 0.0001), and staphyloma depth (P < 0.0001).
  
  
  CONCLUSIONS
  The peripapillary area is tilted inferotemporally in 77.2% of myopic eyes. Peripapillary tilting was markedly greater in older patients. Greater tilt was associated with a thinner choroid, more extensive PPA, and deeper staphyloma.
authors.affiliation: Department of Ophthalmology, Osaka University Medical School, Osaka, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Asai
authors.affiliation: Department of Ophthalmology, Osaka University Medical School, Osaka, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ikuno
authors.affiliation: Topcon Corporation, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Akiba
authors.affiliation: Topcon Corporation, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kikawa
authors.affiliation: Department of Ophthalmology, Osaka University Medical School, Osaka, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Usui
authors.affiliation: Department of Ophthalmology, Osaka University Medical School, Osaka, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Nishida
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000175:diagnosis* / Q000503:physiopathology; D009898:Optic Disk / Q000473:pathology*; D012029:Refraction, Ocular; D015203:Reproducibility of Results; D055213:Retinal Pigment Epithelium / Q000473:pathology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult