title: Retinal nerve fiber layer thickness in glaucomatous Nepalese eyes and its relation with visual field sensitivity.
abstract: BACKGROUND
  To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous Nepalese eyes using spectral domain optical coherence tomography (SD-OCT) and study its relationship with visual field sensitivity.
  
  
  METHODS
  A total of 120 eyes comprising primary open angle glaucoma (POAG), glaucoma suspects (GS), normal tension glaucoma (NTG) and healthy subjects (n=30 cases in each group) underwent a complete ophthalmic examination, including optic nerve head (ONH) evaluation and standard automated perimetry (SAP). RNFL thickness measurements around the optic disk were taken with circular spectral domain optical coherence tomography (SD-OCT) scans. Analysis of variance (ANOVA) was used for comparison of RNFL parameters among various study groups. The relationship of RNFL parameters with visual field (VF) global indices was evaluated with regression analysis.
  
  
  RESULTS
  The mean pRNFL thickness was significantly less in the POAG (64.30±14.45μm, p<0.01), NTG (85.43±9.79μm, p<0.001) and GS (102.0±9.37μm, p<0.001) groups than in the healthy group (109.8±8.32μm). The RNFL was significantly thinner across all quadrants in all study group pairs (p<0.05) except for normal vs. GS (only superior and inferior quadrant, significant). Linear regression plots with RNFL thickness as a predictor of MD and LV demonstrated a strong and statistically significant degree of determination in the POAG group (R(2)=0.203 and 0.175, p=0.013 and 0.021).
  
  
  CONCLUSIONS
  The RNFL thickness measurements with SD-OCT are lower in glaucomatous eyes as compared to age-matched GS and normal eyes in the Nepalese population. A high resolution SD-OCT could aid significantly in the early diagnosis of glaucoma in Nepal.
authors.affiliation: B.P. Koirala Lions Center for Ophthalmic Studies, Institute of Medicine, Nepal. Electronic address: safalkhanal@iom.edu.np.
authors.forename: Safal
authors.initials: S
authors.lastname: Khanal
authors.affiliation: B.P. Koirala Lions Center for Ophthalmic Studies, Institute of Medicine, Nepal.
authors.forename: Madhu
authors.initials: M
authors.lastname: Thapa
authors.affiliation: Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Lyne
authors.initials: L
authors.lastname: Racette
authors.affiliation: University of Auckland, Auckland, New Zealand.
authors.forename: Richard
authors.initials: R
authors.lastname: Johnson
authors.affiliation: College of Optometry, Western University of Health Sciences, Pomona, USA.
authors.forename: Pinakin Gunvant
authors.initials: PG
authors.lastname: Davey
authors.affiliation: Glasgow Caledonian University, Glasgow, UK.
authors.forename: Mahesh Raj
authors.initials: MR
authors.lastname: Joshi
authors.affiliation: B.P. Koirala Lions Center for Ophthalmic Studies, Institute of Medicine, Nepal.
authors.forename: Gauri Shankar
authors.initials: GS
authors.lastname: Shrestha
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D044466:Asian People; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D042241:Early Diagnosis; D005260:Female; D005901:Glaucoma / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009390:Nepal; D009412:Nerve Fibers / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014794:Visual Fields / Q000502:physiology*
keywords: Campo visual; Capa de fibras nerviosas; Glaucoma; Glaucoma primario de ángulo abierto; Nerve fiber layer; Optical coherence tomography; Primary open angle glaucoma; Tomografía de coherencia óptica; Visual field