title: Influence of lamina cribrosa thickness and depth on the rate of progressive retinal nerve fiber layer thinning.
abstract: OBJECTIVE
  To determine whether lamina cribrosa (LC) depth (LCD) and LC thickness (LCT) are associated with a faster rate of progressive retinal nerve fiber layer (RNFL) thinning in primary open-angle glaucoma (POAG).
  
  
  METHODS
  Prospective, observational study.
  
  
  METHODS
  One hundred ten eyes diagnosed with POAG (n = 110 patients) in which RNFL thickness had been measured by serial spectral-domain (SD) optical coherence tomography (OCT) for at least 2.5 years.
  
  
  METHODS
  The participants underwent enhanced depth imaging volume scanning of the optic nerve, and circumpapillary RNFL thickness measurements were obtained using SD OCT. The participants were followed up regularly with serial RNFL thickness measurements at 6-month or longer intervals. Lamina cribrosa depth was measured at 7 equidistant planes and LCT was measured at 3 locations (superior midperipheral, midhorizontal, and inferior midperipheral). The rate of RNFL thinning was determined by linear regression of serial OCT RNFL thickness measurements over time.
  
  
  METHODS
  Factors associated with the rate of OCT RNFL thinning.
  
  
  RESULTS
  A faster rate of RNFL thinning was associated with disc hemorrhage during follow-up (P < 0.001), wider β-zone parapapillary atrophy with Bruch's membrane (P = 0.037), larger global RNFL thickness (P = 0.026), larger LCD (P < 0.001), and smaller LCT (P = 0.002). The association between LCD and the rate of RNFL thinning was explained better using a fractional polynomial model (R(2) = 0.223) than a linear model (R(2) = 0.134; P = 0.010). Davies' test revealed a statistically significant breakpoint for LCD (489.7 μm), above which a faster rate of global RNFL thinning was associated with a larger LCD.
  
  
  CONCLUSIONS
  A thinner LC and a larger LC displacement had a significant influence on the rate of progressive RNFL thinning.
authors.affiliation: Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, South Korea. Electronic address: twkim7@snu.ac.kr.
authors.forename: Tae-Woo
authors.initials: TW
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Konyang University, Kim's Eye Hospital, Myung-Gok Eye Research Institute, Seoul, South Korea.
authors.forename: Mijin
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Applied Statistics, Yonsei University, Seoul, South Korea.
authors.forename: Hyunjoong
authors.initials: H
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D015588:Observer Variation; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields / Q000502:physiology