title: Comparison of prelaminar thickness between primary open angle glaucoma and normal tension glaucoma patients.
abstract: OBJECTIVE
  The thinning of prelaminar tissue and prelamina cupping is known to occur by ischemia, as we see in anterior ischemic optic neuropathy. Since normal tension glaucoma (NTG) is thought to be more related to vascular factor than in primary open-angle glaucoma (POAG), we hypothesized that prelamina thinning may occur prominently in NTG patients. This study investigated the difference in prelaminar tissue thickness between patients with POAG and NTG and verified the factors related to prelaminar thinning.
  
  
  METHODS
  Complete ophthalmic examination including standard automatic perimetry was performed in all patients. The prelaminar tissue thickness was measured in all patients by performing enhanced depth imaging with a Heidelberg Spectralis Optical Coherence Tomography. The retinal nerve fiber layer and optic nerve head parameters were obtained using the Heidelberg Retina Tomography II and Cirrus Optical Coherence Tomography. Various ocular factors and their relationships with prelaminar thickness were analyzed.
  
  
  RESULTS
  The mean prelaminar tissue thickness was significantly thinner in patients with POAG than in those with NTG. The difference in the prelaminar thickness between patients with POAG and those with NTG was greater in the early field defect group than in the moderate and severe field groups. In multivariate analysis, the mean prelaminar thickness was related to the intraocular pressure, mean deviation, cup-disc ratio, and cup volume.
  
  
  CONCLUSIONS
  The prelaminar tissue was thinner in patients with POAG than in patients with NTG, and intraocular pressure had a strong influence on the prelaminar thickness in both POAG and NTG. This may indicate that mechanical compression is the main pathogenic factor in both POAG and NTG.
authors: Department of Ophthalmology and Visual Science, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
authors: Youn Hea
authors: YH
authors: Jung
authors: Department of Ophthalmology and Visual Science, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
authors: Hae-Young L
authors: HY
authors: Park
authors: Department of Ophthalmology and Visual Science, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
authors: Kyoung In
authors: KI
authors: Jung
authors: Department of Ophthalmology and Visual Science, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
authors: Chan Kee
authors: CK
authors: Park
mesh_terms: D005260:Female; D005902:Glaucoma, Open-Angle / Q000473:pathology*; D006801:Humans; D057066:Low Tension Glaucoma / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000473:pathology*; D041623:Tomography, Optical Coherence