JKOS Journal of the Korean Ophthalmological Society J Korean Ophthalmol Soc 0378-6471 2092-9374 Korean Ophthalmological Society 10.3341/jkos.2010.51.2.248 jkos-51-248 Original Article Comparison of Retinal Nerve Fiber Layer Thickness in Early Normal-Tension Glaucoma and Early Primary Open-Angle Glaucoma MoonSun-Kyung MD JunRoo-Min MD, PhD ChoiKyu-Ryong MD, PhD The Institute of Ophthalmology and Optometry, Department of Ophthalmology, Ewha Womans University School of Medicine, Seoul, Korea Address reprint requests to Kyu-Ryong Choi, MD, PhD Department of Ophthalmology, Ewha Womans University School of Medicine, Mok-dong Hospital #911-1 Mok 5-dong Yangcheon-gu, Seoul 158-710, Korea Tel: 82-2-2650-5154, Fax: 82-2-2654-4334, E-mail: ckrey02@ewha.ac.kr 09 2010 07 09 2010 51 2 248 253 29042009 04112009 Copyright © 2010 Korean Ophthalmological Society 2010 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Purpose

To investigate the comparison of retinal nerve fiber layer (RNFL) thickness parameters measured by optical coherence tomography (Stratus OCT 3000TM) and visual field indices in early normal-tension glaucoma (NTG) and early primary open-angle glaucoma (POAG).

 Methods

Sixty-one early normal-tension glaucomatous eyes, 21 early primary open-angle glaucomatous eyes and 34 healthy control eyes were enrolled in this cross-sectional study. Each subject received a visual field test (Humphrey C30–2) and the fast RNFL thickness algorithm test by OCT. The correlations between RNFL thickness and visual field indices were analyzed. The sensitivity and specificity for the detection of early glaucoma were determined with the area under the receiver operating characteristics curve (AUROC).

 Results

All RNFL thickness values except for the temporal quadrant RNFL thickness were significantly decreased in the early NTG and POAG groups (p<0.05). In early POAG, the average and superior quadrant RNFL thicknesses were significantly thinner than in the early NTG group. Significant correlations were observed between the PSD and the average and superior quadrant RNFL thicknesses in the early NTG and POAG groups (p<0.05). The average RNFL thickness for early glaucoma had the widest AUROC among all of the parameters.

 Conclusions

In the early NTG group with visual field defects similar to those of early POAG, RNFL defects measured by OCT were less severe, particularly in the average and superior quadrant RNFLs.

 Normal-tension glaucoma Optical coherence tomography Primary open-angle glaucoma Retinal nerve fiber layer thickness References Quigley HA Addicks EM Green WR Optic nerve damage in human glaucoma. III. Quantitative correlation of nerve fiber loss and visual field defect in glaucoma, ischemic neuropathy, aberrations, and toxic neuropathy Arch Ophthalmol 198210013546 Sommer A Katz J Quigley HA Clinical detectable nerve fiber atrophy precedes the onset of glaucomatous field loss Arch Ophthalmol 19911097783 Von Graefe A ϋ ber die iridectomie bei glaucom und ϋ ber den aberrations usen prozess Albercht von Graefes Arch Ophthalmol 1857 3456650 Levene RZ Low-tension glaucoma: a critical review and new material Surv Ophthalmol 19802462164 Kubota T Khalil AK Honda M Comparative study of retinal nerve fiber layer damage in Japanese patients with normal- and high-tension glaucoma J Glaucoma 199983636 Kook MS Sung K Kim S Study of retinal nerve fiber layer thickness in eyes with high tension glaucoma and hemifield defect Br J Ophthalmol 200185116770 Yamazaki Y Koide C Miyazawa T Comparison of retinal nerve fiber layer in high- and normal-tension glaucoma Graefes Arch Clin Exp Ophthalmol 199122951720 Woo SJ Park KH Kim DM Comparison of localized nerve fiber layer defects in normal tension glaucoma and primary open angle glaucoma Br J Ophthalmol 2003876958 Shields MB Normal-tension glaucoma; is it different from aberrations open-angle glaucoma Curr Opin Ophthalmol 200819858 Mok KH Lee VW So KF Retinal nerve fiber loss in high- and normal-tension glaucoma by optical coherence tomography Optom Vis Sci 20048136972 Quigley HA Katz J Derrick RJ An evaluation of optic disc and nerve fiber layer examinations in monitoring progression of early glaucoma damage Ophthalmology 1992991928 Shin IH Kang SY Kim CY Comparison of OCT and HRT finding among normal, normal tension glaucoma, and high aberrations glaucoma Korean J Ophthalmol 20082223641 Kanamori A Nakamura M Escano MF Evaluation of the glaucomatous damage on retinal nerve fiber layer thickness aberrations by optical coherence tomography Am J Ophthalmol 2003 13551320 Medeiros FA Zangwill LM Bowd C Evaluation of retinal nerve fiber layer, optic nerve head, and macular thickness aberrations for glaucoma detection using optical coherence aberrations Am J Ophthalmol 20051394455 Park SE Jung JK Jung J-Y Park SH Optical coherence aberrations parameters of normal, glaucoma suspect, and early aberrations patients J Korean Ophthalmol Soc 200748137987 Leung CK Mohamed S Leung KS Retinal nerve fiber layer measurements in myopia: an optical coherence tomography study Invest Ophthalmol Vis Sci 20064751716 Figures and Tables

ROC curve for OCT parameters.

Clinical characteristics of the subjects (Mean± SD)

Normal Early NTG Early POAG p-value
No (eyes) 34 61 21
Male: Female 18:16 34:27 18:3
Age(years) 45.38±7.79 48.23±11.0 42.38±12.0 0.072
Refractive error (diopters) −0.94±1.76 −1.82±2.15 −2.79±3.28 0.056
IOP (mm Hg) 15.21±2.29 14.70±2.54 23.24±1.55†‡ 0.000
MD (dB) −0.57±0.69 −2.47±1.47* −2.49±1.46† 0.000
PSD (dB) 1.68±0.28 3.31±2.00* 3.77±2.82† 0.000

NTG=normal-tension glaucoma; POAG=primary open-angle glaucoma; p-value, by analysis of variances (ANOVA)

p<0.05, normal vs. early NTG

p<0.05, normal vs. early POAG

p<0.05, early NTG vs. early POAG.

Comparison of the RNFL thickness (Mean± SD, μm)

Normal Early NTG Early POAG p-value
Superior quadrant 129.2±15.6 113.2±20.4* 99.2±24.9†‡ 0.000
Nasal quadrant 81.5±17.7 64.5±17.4* 60.0±11.5† 0.000
Inferior quadrant 136.8±16.2 116.5±23.1* 108.1±21.0† 0.000
Temporal quadrant 80.3±14.6 80.8±19.1 75.5±24.4 0.536
Average 107.0±8.3 93.8±13.7* 85.7±14.8†‡ 0.000
Twelve o'clock (superior) 130.8±22.7 113.0±24.2* 102.3±28.5† 0.000
One o'clock 128.3±21.5 108.8±31.5* 97.2±27.1† 0.000
Two o'clock 96.1±19.2 83.9±23.1* 81.0±28.5† 0.024
Three o'clock (nasal) 68.8±15.4 59.5±16.0* 63.0±21.1 0.041
Four o'clock 82.9±19.1 73.5±22.4* 71.5±27.0 0.096
Five o'clock 130.6±30.1 116.7±35.7* 111.9±34.7† 0.084
Six o'clock (inferior) 146.5±28.5 120.4±29.6* 116.1±27.3† 0.000
Seven o'clock 133.5±27.9 112.4±34.8* 96.1±36.2† 0.000
Eight o'clock 81.4±17.7 74.6±23.8 61.4±19.7†‡ 0.005
Nine o'clock (temporal) 64.8±14.7 59.8±15.5 55.7±11.5† 0.077
Ten o'clock 91.4±21.6 84.3±27.4 73.5±20.6† 0.036
Eleven o'clock 128.4±25.9 118.1±28.0 98.4±34.7†‡ 0.001

RNFL=retinal nerve fiber layer; NTG=normal-tension glaucoma; POAG=primary open-angle glaucoma; p-value, by analysis of variances (ANOVA)

p<0.05, normal vs. early NTG

p<0.05, normal vs. early POAG

p<0.05, early NTG vs. early POAG.

Pearson's correlation between the RNFL thickness and MD, PSD in early NTG and early POAG

Early NTG
 Early POAG
MD PSD MD PSD
Superior quadrant 0.093 −0.291* 0.440 −0.660*
Nasal quadrant 0.185 −0.269* −0.263 0.016
Inferior quadrant 0.140 −0.195 0.328 −0.372
Temporal quadrant −0.001 −0.163 0.230 −0.382
Average 0.151 −0.333* 0.346 −0.566*

RNFL=retinal nerve fiber layer; NTG=normal-tension glaucoma; POAG=primary open-angle glaucoma; MD=mean deviation; PSD=pattern standard deviation

p<0.05.

Diagnostic accuracy of OCT parameters to discriminate between early NTG and early POAG vs. normal

Normal vs. Early NTG AUROC (95% CI) Normal vs. Early POAG AUROC (95% CI)
Superior quadrant 0.724 (0.619–0.829) 0.824 (0.710–0.938)
Nasal quadrant 0.750 (0.653–0.856) 0.841 (0.737–0.945)
Inferior quadrant 0.755 (0.657–0.852) 0.852 (0.743–0.960)
Temporal quadrant 0.511 (0.394–0.628) 0.565 (0.397–0.733)
Average 0.806 (0.718–0.894) 0.896 (0.807–0.985)

OCT=optical coherence tomography; NTG=normal-tension glaucoma; POAG=primary open-angle glaucoma.