Phacoemulsification Alone vs With Viscogonioplasty in PACG
Phacoemulsification Alone vs With Viscogonioplasty in PACG
Purpose: To compare the effect of phacoemulsification (Phaco) versus combined phacoemulsification and viscogonioplasty (Phaco-VGP) on long-term intraocular pressure (IOP) in primary angle-closure glaucoma (PACG).
Methods: In this prospective randomized clinical trial, 92 eyes of 82 patients with PACG and coexisting cataract were randomized to undergo Phaco alone (46 eyes) or Phaco-VGP (45 eyes) and completed the trial. Anterior segment optical coherence tomography was performed preoperatively and at 1 year after surgery. Main outcome measures were IOP and the number of IOP-lowering medications.
Results: Phaco alone reduced the mean IOP from a preoperative level of 22.3 ± 6.3 to 14.0 ± 3.7 mm Hg at 12 months after surgery (P<0.001). Phaco-VGP reduced the mean IOP from a preoperative level of 23.3 ± 7.3 to 14.5 ± 2.5 mm Hg (P<0.001). There were no statistically significant differences between the 2 groups in IOP and number of medications at all follow-up times. Trabecular-iris space-area measured by anterior segment optical coherence tomography increased significantly after Phaco alone and Phaco-VGP. The amount of the increase was higher in the Phaco-VGP. Although peripheral anterior synechiae (PAS) extent decreased significantly by Phaco alone, Phaco-VGP resulted in significantly greater reduction in PAS extent (P=0.004). The only variables that predicted change in IOP in the whole group were preoperative IOP (β=−0.891, P<0.001) and female sex (β=2.754, P=0.02).
Conclusions: Phaco alone and Phaco-VGP resulted in widening of the drainage angle, reduction of IOP, and PAS extent in PACG eyes. Phaco-VGP resulted in significantly more reduction of PAS and more opening of angle. However, it seems that additional VGP has no significant effect on long-term IOP.
Primary angle-closure glaucoma (PACG) occurs when the anterior chamber (AC) drainage angle progressively narrows with a subsequent rise in intraocular pressure (IOP) leading to glaucomatous optic neuropathy. Recent evidence indicates that a thickened and anterior-positioned lens plays a crucial role in the pathogenesis of PACG, especially in elderly individuals, and that lens extraction is effective in deepening the AC, opening the iridocorneal angle, and lowering the IOP.
However, in chronic cases the trabecular meshwork may remain occluded by peripheral anterior synechiae (PAS) despite AC deepening. In these eyes the trabecular meshwork can be exposed again if PAS are broken by separating the adherent iris from the meshwork. Theoretically, goniosynechialysis can restore trabecular function in eyes with PACG by stripping PAS from the angle and exposing the underlying trabecular meshwork.
Although viscogonioplasty (VGP) has been introduced for breaking PAS in PACG by using heavy viscoelastics like Healon [Abbott Medical Optics (AMO), Abbott Park, IL], recurrence of PAS or permanent damage to the trabecular meshwork might cause the goniosynechialysis to fail to regain aqueous outflow in the long term. In the literature combined phacoemulsification (Phaco) and viscogoniosynechialysis was an effective and safe treatment for management of angle-closure glaucoma. Our previous publication revealed that goniosynechialysis may have some additional effect on drainage angle anatomy. However, few studies have assessed the effect of additional goniosynechialysis to Phaco on long-term IOP in PACG patients.
The objective of this randomized clinical trial is to compare the effects of Phaco alone versus combined phacoemulsification and viscogonioplasty (Phaco-VGP) on long-term IOP and anterior segment parameters in PACG eyes. We used anterior segment optical coherence tomography (AS-OCT) to assess the AC and angle parameters, and evaluated the variables that affect IOP control in PACG eyes after Phaco. This device provides a noncontact assessment of the AC and angle parameters, and allows users to quantify angle width and measure AC dimensions and parameters including novel factors such as lens vault (LV), thus helping researchers in further understanding the pathogenesis of anterior segment disease.
Abstract and Introduction
Abstract
Purpose: To compare the effect of phacoemulsification (Phaco) versus combined phacoemulsification and viscogonioplasty (Phaco-VGP) on long-term intraocular pressure (IOP) in primary angle-closure glaucoma (PACG).
Methods: In this prospective randomized clinical trial, 92 eyes of 82 patients with PACG and coexisting cataract were randomized to undergo Phaco alone (46 eyes) or Phaco-VGP (45 eyes) and completed the trial. Anterior segment optical coherence tomography was performed preoperatively and at 1 year after surgery. Main outcome measures were IOP and the number of IOP-lowering medications.
Results: Phaco alone reduced the mean IOP from a preoperative level of 22.3 ± 6.3 to 14.0 ± 3.7 mm Hg at 12 months after surgery (P<0.001). Phaco-VGP reduced the mean IOP from a preoperative level of 23.3 ± 7.3 to 14.5 ± 2.5 mm Hg (P<0.001). There were no statistically significant differences between the 2 groups in IOP and number of medications at all follow-up times. Trabecular-iris space-area measured by anterior segment optical coherence tomography increased significantly after Phaco alone and Phaco-VGP. The amount of the increase was higher in the Phaco-VGP. Although peripheral anterior synechiae (PAS) extent decreased significantly by Phaco alone, Phaco-VGP resulted in significantly greater reduction in PAS extent (P=0.004). The only variables that predicted change in IOP in the whole group were preoperative IOP (β=−0.891, P<0.001) and female sex (β=2.754, P=0.02).
Conclusions: Phaco alone and Phaco-VGP resulted in widening of the drainage angle, reduction of IOP, and PAS extent in PACG eyes. Phaco-VGP resulted in significantly more reduction of PAS and more opening of angle. However, it seems that additional VGP has no significant effect on long-term IOP.
Introduction
Primary angle-closure glaucoma (PACG) occurs when the anterior chamber (AC) drainage angle progressively narrows with a subsequent rise in intraocular pressure (IOP) leading to glaucomatous optic neuropathy. Recent evidence indicates that a thickened and anterior-positioned lens plays a crucial role in the pathogenesis of PACG, especially in elderly individuals, and that lens extraction is effective in deepening the AC, opening the iridocorneal angle, and lowering the IOP.
However, in chronic cases the trabecular meshwork may remain occluded by peripheral anterior synechiae (PAS) despite AC deepening. In these eyes the trabecular meshwork can be exposed again if PAS are broken by separating the adherent iris from the meshwork. Theoretically, goniosynechialysis can restore trabecular function in eyes with PACG by stripping PAS from the angle and exposing the underlying trabecular meshwork.
Although viscogonioplasty (VGP) has been introduced for breaking PAS in PACG by using heavy viscoelastics like Healon [Abbott Medical Optics (AMO), Abbott Park, IL], recurrence of PAS or permanent damage to the trabecular meshwork might cause the goniosynechialysis to fail to regain aqueous outflow in the long term. In the literature combined phacoemulsification (Phaco) and viscogoniosynechialysis was an effective and safe treatment for management of angle-closure glaucoma. Our previous publication revealed that goniosynechialysis may have some additional effect on drainage angle anatomy. However, few studies have assessed the effect of additional goniosynechialysis to Phaco on long-term IOP in PACG patients.
The objective of this randomized clinical trial is to compare the effects of Phaco alone versus combined phacoemulsification and viscogonioplasty (Phaco-VGP) on long-term IOP and anterior segment parameters in PACG eyes. We used anterior segment optical coherence tomography (AS-OCT) to assess the AC and angle parameters, and evaluated the variables that affect IOP control in PACG eyes after Phaco. This device provides a noncontact assessment of the AC and angle parameters, and allows users to quantify angle width and measure AC dimensions and parameters including novel factors such as lens vault (LV), thus helping researchers in further understanding the pathogenesis of anterior segment disease.
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