Journal List > J Korean Ophthalmol Soc > v.52(5) > 1009036

Park, Park, Kim, Kim, and Kim: Change in Angle Parameters Measured by Anterior Segment Optical Coherence Tomography after Laser Peripheral Iridotomy Alone versus Laser Peripheral Iridotomy and Argon Laser Peripheral Iridoplasty

Abstract

Purpose

To compare the changes in angle parameters after laser peripheral iridotomy (LPI) alone versus LPI and ALPI (argon laser peripheral iridoplasty) in primary angle closure patients by using anterior segment optical coherence tomography (AS-OCT).

Methods

A total of 25 eyes from 17 patients with narrow angles were enrolled in this present study. Eleven eyes in the LPI treatment group and 14 eyes in the LPI and ALPI combined treatment group were evaluated using AS-OCT. The anterior chamber depth (ACD), angle opening distance at 500 μm (AOD 500) and 750 μm (AOD 750), angle recess area at 500 μm (ARA 500) and 750 μm (ARA 750), trabecular-iris space area at 500 μm (TISA 500) and 750 μm (TISA 750), trabecular-iris angle (TIA) were measured. The pre- and post-treatment parameters were compared in each group. The parameter changes after laser treatment were also compared.

Results

AOD 500, AOD 750, ARA 500, ARA 750, TISA 500 and TISA 750 except ACD significantly increased following LPI treatment (p = 0.013, p = 0.010, p = 0.008, p = 0.003, p = 0.006, p = 0.003, p = 0.013, respectively, Wilcoxon signed rank test) and LPI and ALPI combined therapy (p = 0.001, p = 0.001, p = 0.001, p = 0.001, p = 0.001, p = 0.001, p = 0.001, respectively, Wilcoxon signed rank test). The AOD 500 difference, TISA 500 difference, and TISA 750 difference were significantly greater after LPI and ALPI combined therapy than after LPI treatment alone (p = 0.112, p = 0.147, p = 0.049, p =0.037, respectively, Mann-Whitney U-test).

Conclusions

The results from the present study showed LPI alone or LPI and ALPI combined therapy significantly widened the anterior chamber angle and combined therapy showed greater effect than LPI alone.

References

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Figure 1.
(A) Optical coherence tomography image (Visante OCT) with graphic tools for measurement of different anterior chamber dimensions. Anterior chamber depth is measured between the corneal endothelium and a line joining the two opposite iris recesses. (B) Optical coherence tomography (Visante OCT) cross-sectional view through the anterior chamber angle region. Anterior chamber parameters such as AOD 500, AOD 750, ARA 500, ARA 750, TISA 500, TISA 750 and TIA are automatically measured.
jkos-52-566f1.tif
Figure 2.
Angle changes of AS-OCT before and after laser peripheral iridotomy. (A) AS-OCT image showing angle closure before laser peripheral iridotomy. (B) AS-OCT image showing the same angle open after laser peripheral iridotomy.
jkos-52-566f2.tif
Figure 3.
Angle changes of AS-OCT before and after laser peripheral iridotomy and argon laser peripheral iridoplasty. (A) AS-OCT image showing angle closure before laser peripheral iridotomy and argon laser peripheral iridoplasty. (B) AS-OCT image showing the same angle open after laser peripheral iridotomy and argon laser peripheral iridoplasty.
jkos-52-566f3.tif
Table 1.
Comparison of anterior segment-optical coherence tomography (AS-OCT) parameters before only laser peripheral iridot-omy (LPI) versus LPI and argon laser peripheral iridoplasty (ALPI)
Parameter Pre-LPI (mean ± SD) Pre-LPI &ALPI (mean ± SD) p-value*
ACD (mm) 1.89 ± 0.07 1.90 ± 0.33 0.344
AOD 500 (μm) 58.1 ± 17.3 137.0 ± 57.0 0.000
AOD 750 (μm) 89.5 ± 32.4 155.1 ± 89.7 0.095
ARA§ 500 (×10-2 mm2) 7.3 ± 2.4 11.2 ± 5.1 0.058
ARA 750 (×10-2 mm2) 9.1 ± 2.4 14.8 ± 6.4 0.033
TISAΠ 500 (×10-2 mm2) 4.0 ± 1.1 6.7 ± 2.8 0.015
TISA 750 (×10-2 mm2) 5.7 ± 1.2 10.3 ± 4.4 0.005
TIA# (degrees) 6.6 ± 1.9 15.0 ± 5.9 0.000

* Tested by Mann-Whitney U-test;

ACD = anterior chamber depth;

AOD = angle opening distance;

§ ARA = area of recessed angle;

Π TISA = trabecular-iris space area;

# TIA = trabecular-iris angle.

Table 2.
Changes in anterior segment-optical coherence tomography (AS-OCT) parameters before and after laser peripheral iridotomy (LPI)
Parameter Pre-LPI (mean ± SD) Post-LPI (mean ± SD) p-value*
ACD (mm) 1.89 ± 0.07 1.89 ± 0.06 1.000
AOD 500 (μm) 58.1 ± 17.3 143.6 ± 124.8 0.013
AOD 750 (μm) ARA§ 500 (×10-2 mm2) 89.5 ± 32.4 7.3 ± 2.4 202.6 ± 136.4 11.8 ± 5.1 0.010 0.008
ARA 750 (×10-2 mm2) 9.1 ± 2.4 16.1 ± 7.6 0.003
TISAΠ 500 (×10-2 mm2) 4.0 ± 1.1 7.1 ± 3.7 0.006
TISA 750 (×10-2 mm2) 5.7 ± 1.2 11.4 ± 6.6 0.003
TIA# (degrees) 6.6 ± 1.9 15.0 ± 11.5 0.013

* Tested by Wilcoxon signed rank test;

ACD=anterior chamber depth;

AOD=angle opening distance;

§ ARA=area of recessed angle;

Π TISA = trabecular-iris space area;

# TIA = trabecular-iris angle.

Table 3.
Changes in anterior segment-optical coherence tomography (AS-OCT) parameters before and after laser peripheral iridot-omy (LPI) and argon laser peripheral iridoplasty (ALPI)
Parameter Pre-LPI & ALPI (mean ± SD) Post-LPI & ALPI (mean ± SD) p-value*
ACD (mm) 1.90 ± 0.33 1.92 ± 0.25 0.656
AOD 500 (μm) 137.0 ± 57.0 303.4 ± 128.9 0.001
AOD 750 (μm) 155.1 ± 89.7 373.6 ± 169.8 0.001
ARA§ 500 (×10-2 mm2) 11.2 ± 5.1 18.5 ± 7.6 0.001
ARA 750 (×10-2 mm2) 14.8 ± 6.4 26.8 ± 11.1 0.001
TISAΠ 500 (×10-2 mm2) 6.7 ± 2.8 12.3 ± 5.0 0.001
TISA 750 (×10-2 mm2) 10.3 ± 4.4 20.6 ± 8.6 0.001
TIA# (degrees) 15.0 ± 5.9 29.9 ± 9.7 0.001

* Tested by Wilcoxon signed rank test;

ACD =anterior chamber depth;

AOD=angle opening distance;

§ ARA =area of recessed angle;

Π TISA = trabecular-iris space area;

# TIA = trabecular-iris angle.

Table 4.
Comparison in difference of anterior segment-optical coherence tomography (AS-OCT) parameters before and after only laser peripheral iridotomy (LPI) versus laser peripheral iridotomy (LPI) and argon laser peripheral iridoplasty (ALPI)
Parameter LPI (mean ± SD) LPI &ALPI (mean ± SD) p-value*
Δ ACD (mm) 0.00 ± 0.29 0.02 ± 0.13 0.609
Δ AOD 500 (μm) 85.6 ± 120.4 166.4 ± 108.2 0.033
Δ AOD 750 (μm) 113.1 ± 124.0 218.5 ± 164.3 0.112
Δ ARA§ 500 (×10-2 mm2) 4.6 ± 5.4 7.3 ± 5.9 0.147
Δ ARA 750 (×10-2 mm2) 7.0 ± 7.8 12.1 ± 8.9 0.055
Δ TISAΠ 500 (×10-2 mm2) 3.1 ± 3.8 5.5 ± 4.0 0.049
Δ TISA 750 (×10-2 mm2) 5.7 ± 6.5 10.3 ± 7.2 0.037
Δ TIA# (degrees) 8.4 ± 11.1 14.9 ± 8.3 0.052

* Tested by Mann-Whitney U-test;

ACD = anterior chamber depth;

AOD = angle opening distance;

§ ARA = area of recessed angle;

Π TISA = trabecular-iris space area;

# TIA = trabecular-iris angle.

Table 5.
Changes in intraocular pressure (IOP) before and after only laser peripheral iridotomy (LPI) versus laser peripheral iridot-omy (LPI) and argon laser peripheral iridoplasty (ALPI)
IOP before treatment (mmHg) IOP after treatment (mmHg)
Immediately 1 wk 1 mon 3 mon 6 mon
LPI (mean ± SD) 15.0 ± 3.5 14.1 ± 4.4 13.5 ± 2.2 11.8 ± 0.8 17.0 ± 3.5 13.5 ± 2.6
LPI & ALPI (mean ± SD) 18.8 ± 5.1 16.3 ± 4.3 14.4 ± 3.8 15.0 ± 3.9 14.4 ± 2.6 17.8 ± 3.8
p-value* 0.087 0.222 0.767 0.143 0.181 0.059

* Tested by Mann-Whitney U-test.

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