title: Microvascular Compromise Develops Following Nerve Fiber Layer Damage in Normal-Tension Glaucoma Without Choroidal Vasculature Involvement.
abstract: OBJECTIVE
  To investigate capillary densities in patients with unilateral normal-tension glaucoma (NTG) and normal controls using optical coherence tomography-angiography.
  
  
  METHODS
  We recruited 13 patients with unilateral NTG and 13 healthy controls. Optical coherence tomography-angiography was performed and pure peripapillary retinal capillary density was calculated after manually excluding large vessels and the optic disc. Paired comparison of capillary densities was performed among 3 categories of eye: NTG eye, fellow eye, and normal eye. Through vascular layer stratification we investigated differences in the retinal and choroidal circulation.
  
  
  RESULTS
  In total, 33 eyes of 11 unilateral NTG patients and 11 controls were analyzed. Capillary densities of NTG eyes were significantly lower than those of fellow eyes or control eyes (both P=0.013). No significant differences were found between fellow eyes and control eyes (P=0.328). Area of capillary compromise was identical to the area of retinal nerve fiber layer (RNFL) defect in all 11 eyes. In layer analysis, a decrease in capillary plexus was demonstrated only in the inner retina and no definite changes were found in the outer retina and choroid. Optic nerve head microvasculature did not show areas of capillary dropout.
  
  
  CONCLUSIONS
  In patients with unilateral NTG, we could observe significant retinal capillary compromise in the area of RNFL defect. No changes were demonstrated in the choroid and optic disc area. We speculated on a possibility of secondary microvascular changes in the retina to nerve damage from the wedge-shaped but not geographic shaped capillary compromise corresponding to RNFL defect area. Further studies on the optic nerve head microvasculature and blood flow are warranted to assess their relationship to glaucoma pathogenesis.
authors.affiliation: Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Sibum
authors.initials: S
authors.lastname: Kim
authors.forename: Sungsoon
authors.initials: S
authors.lastname: Hwang
authors.forename: Jong Chul
authors.initials: JC
authors.lastname: Han
authors.forename: Changwon
authors.initials: C
authors.lastname: Kee
mesh_terms: D000328:Adult; D002196:Capillaries / Q000473:pathology; D016022:Case-Control Studies; D002829:Choroid / Q000098:blood supply*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D057066:Low Tension Glaucoma / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009898:Optic Disk / Q000473:pathology; D012160:Retina / Q000473:pathology*; D012171:Retinal Vessels / Q000473:pathology*; D041623:Tomography, Optical Coherence