Central Corneal Thickness and Visual Field Progression in Primary Open-Angle Glaucoma

Jin Ha Kim; Eun Kyoung Lee; Chang Sik Kim; Nam Ho Lee

doi:10.3341/jkos.2007.48.8.1088-1095

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Kim, Lee, Kim, and Lee: Central Corneal Thickness and Visual Field Progression in Primary Open-Angle Glaucoma

Original Article

J Korean Ophthalmol Soc 2007;48(8):1088-1095.

Published online: 24 August 2007

DOI: https://doi.org/10.3341/jkos.2007.48.8.1088-1095

Central Corneal Thickness and Visual Field Progression in Primary Open-Angle Glaucoma

Jin Ha Kim, M.D., Eun Kyoung Lee, M.D., Chang Sik Kim, M.D., Nam Ho Lee, M.D.

Department of Ophthalmology, Chung-Nam National University, College of Medicine, DAejeon, Korea

Address Reprint requests to Nam Ho Lee, M.D., Department of Ophthalmology, Chung-Nam National University, College of Medicine, #640 Daesa-dong, Jung-gu, Daejeon 301-721, Korea, Tel: 82-42-220-7602, Fax: 82-42-225-3745, E-mail: geggol@hanmail.net

Received 7 March 2007 Accepted 4 July 2007

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 find difference in the rate of visual field defect progression among primary open angle glaucoma (POAG) patients grouped according to central corneal thickness (CCT).

Methods

The medical records of 87 eyes of 87 POAG patients who received were on regular treatment and had a minimum of 5 years of longitudinal Humphrey automated visual field follow-up were reviewed retrospectively. The patients were divided into 4 quartile groups by CCT, and the correlations among clinical factors, such as intraocular pressure (IOP), and change in mean deviation (MD), were analyzed.

Results

The thinner cornea group showed a significant trend foward higher average, maximal, and yearly maximal IOP when the IOP was corrected by CCT (p<0.01), The rate of change in MD is significantly different; −0.33±0.6dB, −0.28±0.4dB, −0.09±0.2dB,-0.02±0.2dB starting with the thinnest cornea group (p=0.036). Correlation analysis revealed a significant correlation between CCT and the rate of change in MD (r=0.351, p=0.001).

Conclusions

In POAG patients who were on regular treatment at a tertiary referral hospital, patients with thinner cornea showed faster visual field defect progression.

Keywords: Cyclodialysis cleft, Intraocular pressure, Refractive power, Trauma

References

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Figure 1.

Scattergram of changes in mean deviation in automated visual field test and corrected intraocular pressure with central corneal thickness (Pearson correlation test, r=-0.302, p=0.004).

IOP=intraocular pressure in mm Hg; MD=mean deviation in dB in Humphrey automated perimetry.

Rate of MD change (dB/yr)=(final MD - initial MD) / follow-up years.

Figure 2.

Scattergram of central corneal thickness and change in mean deviation in automated visual field test (Pearson correlation test, r=0.351, p=0.001).

CCT=central corneal thickness in μm; MD=mean deviation in dB in Humphrey automated perimetry.

Rate of MD change (dB/yr)=(final MD - initial MD) / follow-up years.

Table 1.

Demographics of the patients

No. of patients (eyes)	87 (87)
Male:Female	59:28
Age, M±SD (range, years)	58.2±9.7 (40∼84)
Laterality (Right : Left)	48:39
Numbers of patients with systemic diseases (%)
Diabetic mellitus	18 (20.7)
Hypertension	18 (20.7)
Cardiovascular disease	2 (2.3)
Thyroid disease	1 (11)
Follow up, M±SD (range, years)	7.2±2.7 (5∼20)
Numbers of surgery during follow-up period (%)
Trabeculectomy	25 (28.7)
Glaucoma implant surgery	3 (3.4)
Phacoemulsification+PC-IOL	25 (28.7)
Central corneal thickness, M±SD (range, pm)	536.9±35.0 (440 ∼ 626)

PC-IOL=posterior chamber intraocular lens.

Table 2.

Patient characteristics grouped by central corneal thickness

(mean±SD)

Group (n)	Group 1 (20)	Group 2 (23)	Group 3 (22)	Group 4 (22)	p-value^∗
CCT	<513 μm	513∼535 μm	536∼557 μm	>557 μm	p-value^∗
Follow up (years)	7.3±2.5	6.4±1.6	8.5±3.7	7.1±2.2	0.077
Age (years)	61.1±9.8	58.0±9.7	55.5±7.4	58.4±10.5	0.301
Sex (male/female)	14/6	15/8	17/5	13/9	0.630
Laterality (Right/Left)	12/8	8/15	14/8	14/8	0.153
Systemic diseases (No)	0.4±0.5	0.3±0.5	0.7±0.8	0.5±0.7	0.179
Number of surgery	0.8±1.2	0.7±0.8	0.5±0.9	0.6±0.9	0.857

^∗ one-way ANOVA test.

CCT=central corneal thickness.

Table 3.

Comparison of intraocular pressure course and changes of cup-disc ratio in 4 groups divided by central corneal thickness

(mean±SD)

Group (n)	Group 1 (20)	Group 2 (23)	Group 3 (22)	Group 4 (22)	p-value^∗
CCT	<513 μm	513∼535 μm	536∼557 μm	>557 μm	p-value^∗
IOP on 1st visit	21.2±3.8	22.2±5.5	19.9±4.0	21.5±4.6	0.397
Glaucoma meds.	1.5±1.2	1.7±0.9	1.7±1.0	1.3±1.2	0.688
on 1st visit
Average IOP	17.4±1.7	17.1±2.4	16.9±1.9	18.5±2.2	0.052
Highest IOP	23.0±4.6	25.8±6.0	22.7±4.8	23.9±4.7	0.186
Yearly max IOP	19.2±3.6	19.8±2.6	18.3±2.3	19.9±2.5	0.210
Yearly variation	4.0±3.1	4.8±2.4	3.1±1.4	3.6±1.4	0.060
Average No. of	1.8±0.8	1.8±0.6	1.5±0.9	1.4±0.8	0.268
glaucoma meds.
Initial C/D ratio	0.78±0.2	0.80±0.2	0.77±0.1	0.69±0.2	0.121
Last C/D ratio	0.87±0.1	0.88±0.1	0.87±0.1	0.78±0.2	0.065
Change of C/D ratio	0.08±0.1	0.08±0.1	0.10±0.1	0.09±0.1	0.894

^∗ one-way ANOVA test.

IOP=intraocular pressure in mmHg; CCT=central corneal thickness.

Table 4.

Comparison of corrected intraocular pressure according to the central corneal thickness in 4 groups divided by central corneal thickness

(mean± SD)

Group (n)	Group 1 (20)	Group 2 (23)	Group 3 (22)	Group 4 (22)	p-value^∗
CCT	<513 μm	513∼535 μm	536∼557 μm	<557 μm	p-value^∗
Average IOP	19.5±3.0	18.2±1.6	16.3±2.0	15.9±2.2	0.000
Highest IOP	26.5±6.1	25.1±4.8	22.2±4.9	21.6±4.8	0.005
Yearly maximal IOP	21.4±3.8	20.6±2.6	17.8±2.3	17.7±2.5	0.000

^∗ one-way ANOVA test.

IOP=intraocular pressure in mmHg; CCT=central corneal thickness.

Table 5.

Comparison of change in mean deviation in Humphrey automated visual field in 4 groups divided by central corneal thickness

(mean± SD)

Group (n)	Group 1 (20)	Group 2 (23)	Group 3 (22)	Group 4 (22)	p-value^∗
CCT	<513 μm	513∼535 μm	536∼557 μm	>557 μm	p-value^∗
MD Initial	-12.4±10.1	-11.0±8.5	-10.0±8.3	-6.0±7.1	0.089
MD Last	-14.2±11.3	-12.9±9.3	-10.6±8.0	-6.1±7.2	0.022
MD Change	-1.9±3.4	-1.9±3.2	-0.6±1.9	-0.2±1.3	0.056
MD Slope^†	-0.33±0.6	-0.28±0.4	-0.09±0.2	-0.02±0.2	0.036

^∗ one-way ANOVA test.

MD=mean deviation in dB in Humphrey automated perimetry; CCT=central corneal thickness.

^† MD Slope: Rate of MD change (dB/yr)=(final MD - initial MD)/follow-up years.

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