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Suh, Jun, and Choi: Longitudinal Analysis of Retinal Nerve Fiber Layer Thickness With GDx-VCC in Glaucoma Suspect
Original Article

J Korean Ophthalmol Soc 2009;50(2):235-241.

Published online: 3 January 2009

DOI: https://doi.org/10.3341/jkos.2009.50.2.235

Longitudinal Analysis of Retinal Nerve Fiber Layer Thickness With GDx-VCC in Glaucoma Suspect

Wool Suh, MD, Roo-Min Jun, MD, Kyu-Ryong Choi, MD

The Institute of Ophthalmology and Optometry, Department of Ophthalmology, College of Medicine, Ewha Womans University, Seoul, Korea

Address reprint requests to Kyu-Ryong Choi, MD Department of ophthalmology, College of Medicine, Ewha Womans University #911-1 Mokdong, Yangcheon-gu, Seoul 158-710, Korea Tel: 82-2-2650-5031, Fax: 82-2-2654-4334, E-mail: ckrey02@mm.ewha.ac.kr

Received 18 August 2008       Accepted 24 November 2008

Copyright © 2009 Korean Ophthalmological Society

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

The changes of retinal nerve fiber layer thickness with GDx-VCC were analyzed to assess the use of this instrument for longitudinal follow-up of retinal nerve fiber layers.

Methods

From July 2004 to July 2007, patients suspected of glaucoma were measured with GDx-VCC at baseline and measurements were repeated at a minimum interval of 12 months. The medical records of 150 patients were reviewed and 42 patients that showed glaucomatous visual field progression in 36 months were classified into a "progression group" and 108 patients with no visual field loss were classified into a "nonprogression group".

Results

In the nonprogression group, the temporal superior-nasal-inferior-temporal (TSNIT) average and theinferior average showed statistically significant changes for the follow up periods. However, in theprogression group, there were no parameters with significant changes even though glaucomatous visual field loss was found. The visual field progressed at a rate of 0.1dB/year in the progression group but the relationship between MD, PSD and GDx-VCC parameters could not be established.

Conclusions

GDx-VCC may not be sufficient for longitudinal assessment of the RNFL, especially during the early glaucomatous visual field changes. The progression of glaucoma only with GDx-VCC should be cautiously evaluated, and confirmation with the visual field which elucidates early glaucomatous changes is necessary. Further study is needed before GDx-VCC can be recommended as the instrument for longitudinal assessment.

Keywords: GDx-VCC, Glaucoma suspect, Visual field

References

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Table 1.
Demographics of study population
Nonprogression group Progression group p-value
No. of eyes 108 42
Age (years) 43.5±9.5 42.0±12.4 >0.05
Gender (male:female) 67:41 21:21
Refraction (diopter) -1.791±2.154 -2.136±3.101 >0.05
IOP* (mmHg) 18.0±4.2 17.7±3.5 >0.05
CD ratio 0.65±0.15 0.67±0.14 >0.05
MD† (dB§) -0.80±1.66 -1.27±1.44 >0.05
PSD‡ (dB§) 1.86±0.57 1.90±0.43 >0.05

* IOP=intraocular pressure;

† MD=mean deviation;

‡ PSD=pattern standard deviation;

§ dB=decibel.

Table 2.
Comparison of baseline GDx-VCC parameters
GDx-VCC parameter Nonprogression group Progression group p-value*
TSNIT average 55.82±6.09 56.42±6.37 >0.05
Superior average 68.44±7.69 69.38±7.74 >0.05
Inferior average 65.33±8.76 67.10±8.47 >0.05
TSNIT Std. Dev 22.50±3.95 24.06±4.89 <0.05
NFI 18.89±8.11 18.73±8.45 >0.05
Superior ratio 3.04±0.88 3.19±1.13 >0.05
Inferior ratio 3.03±0.89 3.21±1.19 >0.05
Superior/Nasal 3.02±0.71 3.30±0.66 <0.05
Max modulation 2.62±0.76 2.99±0.91 <0.05
Superior maximum 80.64±11.02 81.58±10.22 >0.05
Inferior maximun 79.99±10.27 82.01±11.16 >0.05
Ellipse modulation 3.84±1.33 4.31±1.71 >0.05
Normalized superior area 0.14±0.02 0.14±0.02 >0.05
Normalized inferior area 0.14±0.02 0.14±0.02 >0.05

* independent t-test.

Table 3.
Changes of GDx-VCC in nonprogression group
GDx-VCC parameter Baseline Follow up p-value*
TSNIT average 55.82±6.09 56.41±6.64 <0.05
Superior average 68.44±7.69 68.49±7.57 >0.05
Inferior average 65.33±8.76 66.35±9.39 <0.05
TSNIT Std. Dev 22.50±3.95 22.59±4.13 >0.05
NFI 18.89±8.11 19.06±8.77 >0.05
Superior ratio 3.04±0.88 3.03±0.95 >0.05
Inferior ratio 3.03±0.89 3.03±0.95 >0.05
Superior/Nasal 3.02±0.71 3.08±0.78 >0.05
Max modulation 2.62±0.76 2.64±0.91 >0.05
Superior maximum 80.64±11.02 79.99±10.27 >0.05
Inferior maximun 79.99±10.27 81.10±10.88 >0.05
Ellipse modulation 3.84±1.33 3.82±1.31 >0.05
Normalized superior area 0.14±0.02 0.14±0.02 >0.05
Normalized inferior area 0.14±0.02 0.14±0.02 >0.05

* paired t-test.

Table 4.
Changes of GDx-VCC in progression group
GDx-VCC parameter Baseline Follow up p-value*
TSNIT average 56.42±6.37 56.95±7.19 >0.05
Superior average 69.38±7.74 70.13±7.84 >0.05
Inferior average 67.10±8.47 67.67±9.37 >0.05
TSNIT Std. Dev 24.06±4.89 24.31±4.51 >0.05
NFI 18.73±8.45 17.80±7.48 >0.05
Superior ratio 3.19±1.13 3.23±0.95 >0.05
Inferior ratio 3.21±1.19 3.31±1.09 >0.05
Superior/Nasal 3.30±0.66 3.28±0.81 >0.05
Max modulation 2.99±0.91 3.00±0.92 >0.05
Superior maximum 81.58±10.22 82.61±10.67 >0.05
Inferior maximun 82.01±11.16 84.07±12.08 >0.05
Ellipse modulation 4.31±1.71 4.40±1.71 >0.05
Normalized superior area 0.14±0.02 0.14±0.03 >0.05
Normalized inferior area 0.14±0.02 0.14±0.02 >0.05

* paired t-test.

Table 5.
Correlation of glaucoma risk factors and GDx-VCC parameters
GDx-VCC parameter Risk fa actor with statistically significance Unstandardized coefficients p-value*
TSNIT average C/D ratio -9.151 <0.05
Superior average C/D ratio -11.702 <0.05
Inferior average C/D ratio -11.605 <0.05
TSNIT Std. Dev C/D ratio -5.058 <0.05
NFI C/D ratio, refraction, age 0.165, -0.688, 9.156 <0.05
Superior ratio refraction 0.137 <0.05
Inferior ratio refraction 0.137 <0.05
Superior/Nasal refraction -0.061 <0.05
Max modulation - - >0.05
Superior maximum - - >0,05
Inferior maximun C/D ratio -15.477 <0.05
Ellipse modulation - -
Normalized superior area C/D ratio -0.032 <0.05
Normalizedinferior area C/D ratio -0.036 <0.05

* multiple linear regression analysis.

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