Comparison of Clinical Outcomes of Argon Laser Versus Selective Laser Trabeculoplasty in POAG

Joon Jeong Park; Jong Wook Lee; Kyoo Won Lee

doi:10.3341/jkos.2008.49.9.1491

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Park, Lee, and Lee: Comparison of Clinical Outcomes of Argon Laser Versus Selective Laser Trabeculoplasty in POAG

Original Article

J Korean Ophthalmol Soc 2008;49(9):1491-1500.

Published online: 7 September 2008

DOI: https://doi.org/10.3341/jkos.2008.49.9.1491

Comparison of Clinical Outcomes of Argon Laser Versus Selective Laser Trabeculoplasty in POAG

Joon Jeong Park, M.D., Jong Wook Lee, M.D., Kyoo Won Lee, M.D.

Cheil Eye Hospital, Daegu, Korea

Address reprint requests to Joon Jeong Park, M.D.Cheil Eye Hospital #803-2 Sinam 1-dong, Dong-gu, Daegu 701-011, Korea Tel: 82-53-959-1751, Fax: 82-53-959-1758, E-mail: jjparkmd@nate.com

Received 11 June 2008 Accepted 7 September 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 compare the clinical outcomes between patients undergoing argon laser trabeculoplasty (ALT) and those undergoing selective laser trabeculoplasty (SLT).

Methods

Sixty-one eyes of 61 patients with primary open-angle glaucoma who were treated with more than 1 kind of antiglaucoma medication eye drop were enrolled in this study. Thirty-five eyes of 35 patients were treated with argon laser trabeculoplasty (ALT). Twenty-six eyes of 26 patients were treated with selective laser trabeculoplasty (SLT). The mean IOP at 1, 3, 6, and 12 months and the success rate of treatment at the 12-month follow-up period were evaluated in all patients.

Results

At 12 months postoperative, the ALT group had a mean IOP of 16.53±2.58 mmHg with a mean IOP reduction of 35.27%, while the SLT group had a mean IOP of 18.40±5.61 mmHg with a mean IOP reduction of 17.37%. The success rates of treatment defined as definition 1 were 62.85% in ALT and 62.50% in SLT, and the success rates defined as definition 2 were 51.42% in ALT and 46.15% in SLT.

Conclusions

There were no significant differences in the IOP lowering effect or success rates between the ALT and SLT patients at 12 months postoperatively.

Keywords: Argon laser trabeculoplasty, Nd, YAG laser, Primary open angle glaucoma, Selective laser trabeculoplasty

References

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Figure 1.

Mean IOP reduction percent during follow-up period; * There were significant statistical differences between the two groups at 3, 6, 12 months; ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty.

Figure 2.

Kaplan-Meier survival curve using definition 1 (failure defined as a decrease in IOP of 3 mmHg or less of the baseline IOP and needs for additional medication, additional laser or glaucoma surgery) in ALT and SLT groups. There were no significant statistical differences between the two groups during the follow-up period; Cum=cumulative; n=number of all eyes defined as success of treatment by definition 1 in each group at each time point; ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty.

Figure 3.

Kaplan-Meier survival curve using definition 2 (failure defined as a decrease in IOP of 20% or less of the baseline IOP and needs for additional medication, additional laser or glaucoma surgery) in ALT and SLT groups. There were no significant statistical differences between the two groups during the follow-up period; Cum=cumulative; n=number of all eyes defined as success of treatment by definition 2 in each group at each time point. ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty.

Table 1.

Patient demographics at baseline

	ALT	SLT	p-value
Number of subjects (eye)	35 (35)	26 (26)
Age (year) (Mean±SD)	52.31±13.15	58.27±11.79	0.07*
Sex, n (%)
Male	30 (85.7%)	19 (73.1%)	0.64^†
Female	5 (14.3%)	7 (26.9%)
Diagnosis, n (%)
POAG	35 (100.0%)	26 (100.0%)
Degrees of glaucomatous visual field loss, n (%)			0.71^††
Early glaucomatous loss	3 (8.5%)	4 (15.4%)
Moderate glaucomatous loss	14 (40%)	10 (38.4%)
Advanced glaucomatous loss	18 (51.5%)	12 (46.2%)
Baseline IOP (Mean±SD)	25.54±8.16	22.27±9.43	0.27∗
No. of glaucoma medication at baseline (Mean±SD)	3.65±0.98	2.64±1.50	0.65^‡

POAG=primary open angle glaucoma; ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty

^∗ Two-tailed unpaired t-test

^† Chi-square test

^‡ Mann-Whitney U-test

Table 2.

Intraocular pressure (Mean±SD) during the follow-up period

Time	IOP of ALT group (mmHg)	IOP of SLT group (mmHg)	p-value∗
Baseline	25.54±8.16	22.27±9.43	0.27
1 day	17.31±10.31	15.15±8.73	0.10
1 week	20.69±9.72	18.85±8.78	0.22
1 month	17.37±5.18	18.50±5.72	0.15
3 months	16.04±3.63	18.68±3.54	0.21
6 months	16.54±4.88	18.60±5.81	0.20
12 months	16.53±2.58	18.40±5.61	0.19

ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty

^∗ Two-tailed unpaired t-test.

Table 3.

Mean IOP reduction (Mean±SD) during the follow-up period

Time	No. of case in ALT	IOP reduction of ALT group (mmHg)	No. of case in SLT	IOP reduction of SLT group (mmHg)	∆ IOP reduction of two group (ALT-SLT)	p-value∗
1 day	35	8.23±2.52 (32.22%)	26	7.12±2.10 (31.97%)	+1.11±0.75	0.38
1 week	35	4.85±3.25 (18.98%)	26	3.42±3.21 (15.35%)	+1.43±0.12	0.54
1 month	30	8.17±4.05 (31.98%)	24	3.77±3.72 (16.92%)	+4.14±1.12	0.13
3 months	27	9.50±5.21 (37.19%)	26	3.59±4.10 (16.12%)	+5.12±0.98	0.02
6 months	27	9.00±4.17 (35.23%)	26	3.67±3.18 (16.47%)	+5.14±1.15	<0.01
12 months	26	9.01±3.18 (35.27%)	26	3.87±3.10 (17.37%)	+5.12±0.82	0.03

ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty;

^∗ Two-tailed paired t-test.

Table 4.

Mean IOP reduction of subgroups in ALT and SLT group using definition 1

	Baseline IOP (mmHg)	Post IOP after 12 month (mmHg)	∆ IOP (mmHg)	p-value∗
Success subgroup in ALT (n=22, 62.85%)	23.62±6.02	15.61±2.97	-8.01±4.93	<0.001
Failure subgroup in ALT (n=13, 37.15%)	28.79±10.33	27.28±10.84	-1.52±5.06	0.62
Success subgroup in SLT (n=16, 62.50%)	29.97±11.06	17.24±3.66	-12.72±13.67	0.03
Failure subgroup in SLT (n=10, 37.50%)	20.44±8.27	20.30±7.45	-0.13±6.41	0.96

ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty

^∗ Two-tailed paired t-test.

Table 5.

Mean IOP reduction of subgroups in ALT and SLT group using definition 2

	Baseline IOP (mmHg)	Post IOP after 12 month (mmHg)	∆ IOP (mmHg)	p-value∗
Success subgroup in ALT (n=18, 51.42%)	24.09±6.44	15.17±2.99	-37.0%	<0.001
Failure subgroup in ALT (n=17, 48.58%)	27.08±9.61	25.00±10.34	-7.7%	0.58
Success subgroup in SLT (n=12, 46.15%)	31.79±11.87	17.47±4.18	-45.0%	0.04
Failure subgroup in SLT (n=14, 53.85%)	20.54±8.08	20.12±7.32	-2.0%	0.91

ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty

^∗ Two-tailed paired t-test.

Table 6.

Predictive factors for failure of treatment by definition 1 and definition 2

	ALT group		SLT group
	Definition I	Definition II	Definition I	Definition II
Factors	p valuetable∗	p value∗	p value∗	p value∗
Baseline IOP	0.12	0.268	0.04	0.025
Age	0.25	0.38	0.29	0.35
Perimetric grade	0.27	0.31	0.26	0.30
No. of medication	0.27	0.48	0.29	0.37
Laser spot count	0.28	0.37	0.29	0.38

ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty; Definition 1=failure defined as a decrease in IOP of 3 mmHg or less and needs for additional medication, additional laser or glaucoma surgery; Definition 2=failure defined as a decrease in IOP of 20% or less of baseline IOP and needs for additional medication, additional laser or glaucoma surgery;

^∗ univariable analysis.

Table 7.

Mean number of medications in ALT versus SLT at baseline and 12 months

	ALT group (mean±SD)	SLT group (mean±SD)	p-value∗
Baseline	3.65±1.05	2.64±0.75	0.73
12 months	3.19±0.72	2.54±0.50	0.62

ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty

^∗ Mann-Whitney U-test.

Table 8.

Early inflammation in the anterior chamber and early IOP elevation in ALT versus SLT

	ALT group	SLT group	p-value∗
Inflammation in AC	24 (68.5%)	6 (23%)	0.001
Early IOP elevation	6 (17.1%)	4 (15.3%)	0.95

ALT=argon laser trabeculoplasty; SLT=selective laser trabeculoplasty; AC=anterior chamber.

^∗ Chi-square test.

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