Short-Term Clinical Outcomes of Laser Trabeculoplasty Using a 577-nm Wavelength Laser

Jong Min Kim; Kyong Jin Cho; Sung Eun Kyung; Moo Hwan Chang

doi:10.3341/jkos.2014.55.4.563

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Kim, Cho, Kyung, and Chang: Short-Term Clinical Outcomes of Laser Trabeculoplasty Using a 577-nm Wavelength Laser

Original Article

J Korean Ophthalmol Soc 2014;55(4):563-569.

Published online: 7 September 2014

DOI: https://doi.org/10.3341/jkos.2014.55.4.563

Short-Term Clinical Outcomes of Laser Trabeculoplasty Using a 577-nm Wavelength Laser

Jong Min Kim, MD, Kyong Jin Cho, MD, Sung Eun Kyung, MD, PhD, Moo Hwan Chang, MD, PhD

Department of Ophthalmology, Dankook University Medical College, Cheonan, Korea

Address reprint requests to Moo Hwan Chang, MD, PhD Department of Ophthalmology, Dankook University Hospital,#201 Manghyang-ro, Dongnam-gu, Cheonan 330-715, Korea, Tel: 82-41-550-6497, Fax: 82-41-561-0137 E-mail: changmh@dankook.ac.kr

Received 8 July 201311 October 2013 Accepted 20 February 2014

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 evaluate the pressure-lowering effects of single-spot laser trabeculoplasty and patterned laser trabeculoplasty using a 577-nm wavelength laser.

Methods

A total 35 eyes of 35 patients with primary open-angle glaucoma were enrolled in this study. Eighteen eyes of 18 patients were treated with 360° single-spot laser trabeculoplasty and 17 eyes of 17 patients were treated with 360° patterned laser trabeculoplasty. All patients were evaluated after laser trabeculoplasty at 1 week, 1 month, 3 months, and 6 months using slit lamp examination and Goldmann applanation tonometry.

Results

At 6 months postoperatively, the single-spot laser trabeculoplasty group had a mean IOP of 15.89 ± 3.89 mm Hg with a mean IOP reduction of 37.1%, while the patterned laser trabeculoplasty group had a mean IOP of 17.57 ± 2.64 mm Hg with a mean IOP reduction of 27.1%.

Conclusions

Laser trabeculoplasty with a 577-nm optically pumped semiconductor laser was safe and demonstrated an IOP lowering effect. There were no significant differences in the IOP lowering effects between the single-spot laser trabeculoplasty and the patterned laser trabeculoplasty.

Keywords: Laser trabeculoplasty, PASCAL, Pattern laser trabeculoplasty

References

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Figure 1.

Graphic user interface for patterned laser trabeculoplasty software.

Figure 2.

Procedure of patterned laser trabeculoplasty. (A) Schematic view of patterned laser trabeculoplasty. Pattern of Aiming beam (635 nm) is projected on trabecular meshwork. Once a physician presses the foot pedal, PASCAL photo-coagulator delivers a patterned laser on trabecular meshwork. (B) After shooting the laser, the pattern is automatically ro-tated clockwise by 11.25˚. (C) Gonioscopic view of patterned laser trabeculoplasty.

Figure 3.

Changes in mean intraocular pressure after laser trabeculoplasty. No statistical differences between the groups during follow-up (p > 0.05, Mann-Whitney test). SLT = single spot laser trabeculoplasty; PLT = patterned laser trabeculoplasty.

Figure 4.

Kaplan-Meier survival curve using success defi-nition in single spot laser trabeculoplasty and patterned laser trabeculoplasty groups. No statistical differences between the groups during follow-up (p = 0.93). Cum = cumulative; SLT = single spot laser trabeculoplasty; PLT = patterned laser trabeculoplasty.

Table 1.

Patient demographics

	Single spot laser group	Patterned laser group	p-value
Age (years)	53 ± 16.59 (19-72)	46 ± 9.5 (35-65)	0.30^*
Sex :			0.87^†
Male	10	8
Female	8	9
Mean number of glaucoma medication (n, range)	0.81 ± 1.17 (0-3)	1.30 ± 1.25 (0-3)	0.44^*
Baseline IOP (mm Hg, range)	25.27 ± 7.51 (18-32)	24.11 ± 4.17 (19-45)	0.91^*
Mean duration of increased IOP (month)	2.44 ± 1.69 (1-5)	2.35 ± 1.59 (1-6)	0.64^*
Degrees of glaucomatous visual field loss (month, range)			0.49^†
Early defect	7	8
Moderate defect	5	5
Severe defect	4	6

Values are presented as mean ± SD.

IOP = intraocular pressure.

^* Mann-Whitney U-test

^† Chi-square test.

Table 2.

Changes of mean intraocular pressure during 6 months of follow-up

Time	Single spot laser group			Patterned laser group
Time	Number of eyes	IOP (mm Hg)	p-value^*	Number of eyes	IOP (mm Hg)	p-value^*
Baseline	18	25.27 ± 7.51 (18-32)		17	24.11 ± 4.17 (19-45)
1 week	18	18.09 ± 4.44 (12-25)	0.01	17	17.78 ± 2.49 (14-21)	0.01
1 month	16	19.44 ± 5.15 (10-26)	0.02	15	19.44 ± 5.15 (12-20)	0.03
3 months	16	17.67 ± 5.13 (11-23)	0.02	15	18.43 ± 1.40 (17-20)	0.02
6 months	18	15.89 ± 3.89 (11-21)	0.01	17	17.57 ± 2.64 (15-22)	0.03

Values are presented as mean ± SD.

^* Wilcoxon signed ranks test.

Table 3.

Success rate of laser trabeculoplasty

	Success	Failure
IOP decreased	Success	IOP increased
Single spot laser trabeculoplasty	50% (9)	44.44% (8)	5.56% (1)
Patterned laser trabeculoplasty	52.94% (9)	47.06% (8)	0% (0)
p-value^*	0.87

IOP = intraocular pressure.

^* Chi-square test.

Table 4.

Mean IOP reduction of subgroups between single spot laser trabeculoplasty and patterned laser trabeculoplasty groups using success definitions

		Baseline IOP (mm Hg)	IOP after 6 months (mm Hg)	p-value^*
SLT	Success subgroup (n = 9)	27.40 ± 10.08 (19-45)	14.50 ± 2.88 (11-18)	0.01
	Failure subgroup (n = 9)	23.50 ± 3.45 (19-29)	17.00 ± 4.16 (11-21)	0.42
	p-value^†	0.03	0.16
PLT	Success subgroup (n = 9)	26.80 ± 3.27 (24-32)	17.50 ± 2.08 (15-20)	0.01
	Failure subgroup (n = 8)	20.75 ± 2.22 (18-23)	17.67 ± 3.79 (15-22)	0.06
	p-value^†	0.01	0.30

Values are presented as mean ± SD.

IOP = intraocular pressure; SLT = single spot laser trabeculoplasty; PLT = patterned laser trabeculoplasty.

^* Wilcoxon signed ranks test; † Mann-Whitney U-test.

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