title: Nerve fiber layer in glaucomatous hemifield loss: a case-control study with time- and spectral-domain optical coherence tomography.
abstract: OBJECTIVE
  To evaluate the retinal nerve fiber layer measurements with time-domain (TD) and spectral-domain (SD) optical coherence tomography (OCT), and to test the diagnostic ability of both technologies in glaucomatous patients with asymmetric visual hemifield loss.
  
  
  METHODS
  36 patients with primary open-angle glaucoma with visual field loss in one hemifield (affected) and absent loss in the other (non-affected), and 36 age-matched healthy controls had the study eye imaged with Stratus-OCT (Carl Zeiss Meditec Inc., Dublin, California, USA) and 3 D OCT-1000 (Topcon, Tokyo, Japan). Peripapillary retinal nerve fiber layer measurements and normative classification were recorded. Total deviation values were averaged in each hemifield (hemifield mean deviation) for each subject. Visual field and retinal nerve fiber layer "asymmetry indexes" were calculated as the ratio between affected versus non-affected hemifields and corresponding hemiretinas.
  
  
  RESULTS
  Retinal nerve fiber layer measurements in non-affected hemifields (mean [SD] 87.0 [17.1] µm and 84.3 [20.2] µm, for TD and SD-OCT, respectively) were thinner than in controls (119.0 [12.2] µm and 117.0 [17.7] µm, P<0.001). The optical coherence tomography normative database classified 42% and 67% of hemiretinas corresponding to non-affected hemifields as abnormal in TD and SD-OCT, respectively (P=0.01). Retinal nerve fiber layer measurements were consistently thicker with TD compared to SD-OCT. Retinal nerve fiber layer thickness asymmetry index was similar in TD (0.76 [0.17]) and SD-OCT (0.79 [0.12]) and significantly greater than the visual field asymmetry index (0.36 [0.20], P<0.001).
  
  
  CONCLUSIONS
  Normal hemifields of glaucoma patients had thinner retinal nerve fiber layer than healthy eyes, as measured by TD and SD-OCT. Retinal nerve fiber layer measurements were thicker with TD than SD-OCT. SD-OCT detected abnormal retinal nerve fiber layer thickness more often than TD-OCT.
authors.affiliation: Department of Ophthalmology, Universidade de São Paulo, Brazil. alexandrescreis@gmail.com
authors.forename: Alexandre Soares Castro
authors.initials: AS
authors.lastname: Reis
authors.forename: Kallene Summer Moreira
authors.initials: KS
authors.lastname: Vidal
authors.forename: André Carvalho
authors.initials: AC
authors.lastname: Kreuz
authors.forename: Mario Luiz Ribeiro
authors.initials: ML
authors.lastname: Monteiro
authors.forename: Marcelo Teixeira
authors.initials: MT
authors.lastname: Nicolela
authors.forename: Roberto Freire Santiago
authors.initials: RF
authors.lastname: Malta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D041623:Tomography, Optical Coherence; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*