Corneal changes after a single session of selective laser trabeculoplasty for open-angle glaucoma

Purpose

To investigate the changes in endothelial cell count, central corneal thickness (CCT), and refractive error after a session of selective laser trabeculoplasty (SLT) for open angle glaucoma (OAG).

Methods

This prospective cohort study recruited 111 eyes of 66 consecutive subjects with OAG. Subjects received SLT to 360° of the trabecular meshwork. Endothelial cell count, CCT, and spherical equivalent were measured at baseline before SLT as well as at 1 week and 1 month post SLT. A repeated measure nested ANOVA with Tukey''s multiple comparison test was performed to compare the outcome measures before and after SLT.

Results

In 111 eyes of 66 subjects, the mean number of laser applications per treatment was 166.9±41.4 with a mean energy level of 1.0±0.07 mJ. The mean endothelial cell count decreased significantly from 2465.0±334.0 cells/mm² at baseline to 2355.0±387.0 cells/mm² at 1 week (P=0.0004) but increased to baseline levels at 1 month post SLT (2424.0±379.4 cells/mm², P=0.3). The CCT, which decreased from a baseline of 549.4±37.6 to 543.9±40.2 μm at 1 week post SLT (P=0.02), also returned to the baseline level by 1 month (P=0.2). The spherical equivalent was static from baseline. A positive correlation was found between total laser energy and CCT at 1 month post treatment (r=0.3, P=0.005).

Conclusion

The transient reductions in endothelial cell count and CCT following SLT returned to baseline levels 1 month after the procedure. Patients undergoing SLT should be aware of the risk of potential corneal changes.     

Matrix metalloproteinases and their tissue inhibitors after selective laser trabeculoplasty in pseudoexfoliative secondary glaucoma

Background  

The aim of this study was to assess changes in metalloproteinases (MMP-2) and tissue inhibitor of metalloproteinases (TIMP-2) following selective laser trabeculoplasty (SLT) in patients with pseudoexfoliative glaucoma (PEXG).     

Efficacy of selective laser trabeculoplasty following incisional glaucoma surgery

AIM: To evaluate the efficacy of selective laser trabeculoplasty (SLT) in glaucomatous eyes with previous incisional glaucoma surgery. METHODS: A retrospective cohort of eyes that underwent SLT at a single institution from 2013-2015 were followed for 1y. Reduction in intraocular pressure (IOP) following SLT was evaluated in eyes with prior trabeculectomy with ExPress mini shunt (Alcon, Ft Worth, TX, USA), Ahmed valve (New World Medical, Cucamonga, CA, USA), or combined phacoemulsification-trabeculectomy. A control group was included with eyes without prior surgery that underwent SLT. Success was defined as >20% drop in IOP from pre-SLT baseline. RESULTS: One-hundred and six eyes were included with 53 in both the prior glaucoma surgery (PGS) and no prior glaucoma surgery (NPGS) groups. Mean pre-SLT IOP was 19.2±4.3 and 20.6±6.0 mm Hg for PGS and NPGS groups, respectively (P=0.17). Both groups produced statistically significant IOP reductions at 1 and 6mo (P<0.04). At 6mo, mean IOP reduction reached 7.3% and 10.8% for the PGS and NPGS groups, respectively (P=0.42). Overall, 27.9% and 31.7% of eyes in PGS and NPGS groups met success criteria at 1y (P=0.70). In the PGS group, eyes with baseline IOP ≥21 mm Hg had IOP reductions of 18.1% (P<0.001), 16.7% (P<0.01), and 8.4% (P=0.31) compared to eyes with baseline IOP <21 mm Hg who had IOP reductions of 2.3% (P=0.39), 3.4% (P=0.19), and 1.1% (P=0.72) at 1, 6mo, and 1y, respectively. CONCLUSION: SLT is efficacious in eyes with prior incisional glaucoma surgery and results in similar IOP reductions compared to eyes without PGS. A larger IOP reduction is observed following SLT in eyes with higher pre-SLT IOP.     

Corneal biomechanics predict the outcome of selective laser trabeculoplasty in medically uncontrolled glaucoma

Purpose

To evaluate the predictive value of clinical parameters, including biomechanical properties on the outcome of selective laser trabeculoplasty (SLT) in medically uncontrolled open angle glaucoma (OAG).

Methods

Sixty-eight eyes from 68 patients with OAG and IOP insufficiently regulated by topical medications were enrolled. Patients’ follow-up occurred 6 and 12 months after the procedure. The recorded parameters intraocular pressure (IOP), angle characteristics, central corneal thickness (CCT) and biomechanical properties of the eyes, including corneal hysteresis CH and corneal resistance factor CRF measured with the Ocular Responses Analyzer (ORA, Reichert Ophthalmic Instruments) were tested on their predictive value of SLT-induced IOP lowering effect using correlation analyses and regression models.

Results

Mean IOP reduction 12 months after SLT was 4.2?±?5.7 mmHg (23.2 %, from baseline 18.1?±?5.2 mmHg). The preoperative IOP correlated significantly with IOP reduction (maximum Spearman’s correlation r?=?0.75, p?<?0.001). In linear regression analysis, the corneal biomechanical properties (CH and CRF) together with the baseline IOP revealed good modelling for the IOP lowering effect of SLT (R²?=?0.64, respectively).

Conclusions

In addition to the baseline IOP biomechanical properties (CH and CRF) are significant predictors of SLT induced IOP lowering effect in medically uncontrolled OAG.     

Corneal topographic alterations after selective laser trabeculoplasty

Purpose

To investigate the presence of corneal alterations in the long term among patients with primary open-angle glaucoma (POAG) after a single session of selective laser trabeculoplasty (SLT) treatment.

Materials and methods

The files of the POAG patients who had been treated with SLT were evaluated retrospectively. The Pretreatment Scheimpflug corneal topographic (SCT) findings were then compared with the post-treatment findings.

Results

The files of 33 patients were eligible. The changes in central corneal thickness, thinnest point of cornea, and posterior corneal asphericity at 5 and 8 mm were statistically significant (p = 0.03, 0.01, 0.02, and 0.04 respectively). On the other hand, the simulated K, anterior 3 mm K, anterior 5 mm K, posterior 3 mm K, posterior 5 mm K, anterior asphericity at 3 mm, posterior asphericity at 3 mm, and Zernike values did not change significantly following the treatment (p = 0.19, 0.08, 0.1, 0.3, 0.2, 0.75, 0.09, and 0.3 respectively).

Conclusion

SLT can slightly alter pretreatment SCT findings in 3–6 months. Clinicians should wait for at least 6 months after SLT before performing any subsequent surgeries that depend on corneal parameters.

     

选择性激光小梁成形术治疗青光眼的研究进展

青光眼是世界第二位不可逆的致盲性眼病,一旦确诊,需要长期治疗。激光治疗已经成为青光眼治疗的3个主要手段之一,其中选择性激光小梁成形术（SLT）可选择性地作用于色素性小梁组织,使靶组织收缩,房水外流通畅,从而降低青光眼患者的眼压,但其具体作用机制复杂,目前尚不完全明确。由于其对小梁网组织破坏程度轻微,术后反应较轻,且对邻近组织无损伤,因此是一种安全且可重复治疗的手段,并且不会影响青光眼的下一步治疗。就SLT的原理及SLT临床应用的背景、临床疗效、治疗的安全性等进行综述。     

Evaluating selective laser trabeculoplasty versus argon laser trabeculoplasty in pseudoexfoliation glaucoma patients

Objective

Laser trabeculoplasty effectively reduces intraocular pressure (IOP) in primary open angle glaucoma, with argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT) showing equivalent outcomes. However, it is unclear which laser modality is more effective in pseudoexfoliation (PXE) glaucoma. This study aims to compare the effectiveness of ALT and SLT in PXE glaucoma.

选择性激光小梁成形术治疗开角型青光眼的研究进展

选择性激光小梁成形术（selective laser trabeculoplasty,SLT）采用倍频Q开关Nd：YAG激光,选择性作用于色素小梁网,而对邻近无色素小梁网不产生热损伤和凝固性破坏,目前对其作用机制的研究多集中于细胞因子的作用和后基因水平的改变.在SLT问世之初主要应用于原发性开角型青光眼的治疗,随着对其研究的深入,近年来SLT又被证明对其他类型的开角型青光眼也是安全有效的.在传统治疗参数的基础上,有学者认为低能量激光可以取得更好的疗效.目前已证实的影响SLT的降压效果的因素为基线眼压,基线眼压越高,效果越好.SLT术后常见的并发症包括一过性眼压升高、前房炎性反应以及结膜充血等.SLT的治疗能量与范围的选择、是否能替代传统的药物治疗而作为原发性开角型青光眼患者的初始治疗方法及其与药物配合治疗的最佳方案等问题仍需进一步研究探讨.     

选择性激光小梁成形术治疗原发性青光眼的疗效

目的 评价选择性激光小梁成形术(selective laser trabeculoplasty,SLT)治疗原发性开角型青光眼(primary open-angle glaucoma,POAG)和原发性慢性闭角型青光眼(chronic primary angle-closure glaucoma,CPACG)的疗效及安全性.方法 收集我院眼科2007年1月至2008年1月就诊的原发性青光眼患者34例61眼,其中POAG组患者18例34眼,CPACG组患者16例27眼,2组均应用SLT治疗.观察患者术后1 h、1 d、1周、1个月、3个月、6个月的眼压以及术后6个月视力、视野、房角及角膜内皮细胞数等变化.结果 2组患者眼压在激光治疗后均有显著下降,POAG组患者术前平均眼压为(25.2±2.2)mmHg(1 kPa=7.5 mmHg),术后1 h、1 d、1周、1个月、3个月、6个月眼压分别为(28.9±1.3)mmHg、(17.0±1.9)mmHg、(19.9±1.7)mmHg、(20.1±1.8)mmHg、(18.2±2.1)mmHg、(18.0±2.1)mmHg.CPACG组患者术前平均眼压为(24.9±2.1)mmHg,术后对应时间点眼压分别为(29.3±1.6)mmHg、(16.9±2.0)mmHg、(20.3±1.8)mmHg、(19.3±1.9)mmHg、(20.1±2.0)mmHg、(18.9±2.2)mmHg.2组术后1 d、1周、1个月、3个月、6个月的眼压与术前相比明显下降,差异均有统计学意义(P均<0.05).术后1 d眼压下降最明显,术后一过性眼压升高为最常见的并发症.术后6个月2组患者随访视力、前房角、视野、角膜内皮细胞计数与术前比较均无明显变化.结论 SLT可以安全有效地降低POAG和房角大部分开放的CPACG患者的眼压.     

Selective laser trabeculoplasty in patients with pseudoexfoliative glaucoma vs primary open angle glaucoma: a one-year comparative study

AIM: To compare the efficacy of single-session 360-degree selective laser trabeculoplasty (SLT) for reduction of intraocular pressure (IOP) in patients with pseudoexfoliative glaucoma (PXFG) and primary open angle glaucoma (POAG). METHODS: This is a single-center, prospective, nonrandomized comparative study. Patients older than 18 years of age with uncontrolled PXFG or POAG eyes requiring additional therapy while on maximally tolerated IOP-lowering medications were included. The primary outcome measure changed in IOP from baseline. Success was defined as IOP reduction ≥20% from baseline without any additional IOP-lowering medication. All patients were examined at 1d, 1wk, 1, 3, 6, 9, 12mo after SLT. RESULTS: Nineteen patients (20 eyes) with PXFG and 27 patients (28 eyes) with POAG were included in the study. In the visual fields mean deviation was -2.88 (±1.67) in the POAG and -3.1 (±1.69) in the PXFG groups (P=0.3). The mean (±SD) IOP was 22.9 (±3.7) mm Hg in the POAG group and 25.7 (±4.4)?mm Hg in the PXFG group at baseline and decreased to 18.4 (±3.2) and 18.0 (±3.9) mm Hg in the POAG group (P<0.001 and P=0.02), and to 17.9 (±4.0) and 21.0 (±6.6) mm Hg in the PXFG group (P<0.001 and P=0.47) at 6 and 12mo, respectively. The number of medications was 2.6 (±0.8) in the POAG group and 2.5 (±0.8) in the PXFG group at baseline, and did not change at all follow-up visits in both groups (P=0.16 in POAG and 0.57 in PXFG). Based on Kaplan-Meier survival analysis, the success rate was 75% in the POAG group compared to 94.1% in the PXFG group (P=0.08; log rank test) at 6mo, and 29.1% and 25.0% at 12mo, respectively (P=0.9; log rank). CONCLUSION: The 360-degree SLT is an effective and well-tolerated therapeutic modality in patients with POAG and PXFG by reducing IOP without any change in number of medications. The response was more pronounced early in the postoperative period in patients with PXFG whereas there was no statistically significant difference at 12-month follow-up.     

选择性激光小梁成形术治疗开角型青光眼的研究进展

激光用于青光眼的治疗已有近35a的历史。近年来,选择性激光小梁成形术(SLT)以其安全、有效降眼压、并发症少等优点逐渐成为开角型青光眼的首选治疗。选择性激光小梁成形术是治疗开角型青光眼的一种新型激光手术,它应用倍频Q-开关、波长532nm的Nd:YAG激光,选择性作用于色素性小梁组织达到降低眼压目的。与氩激光小梁成形术(argonlasertrabeculoplasty,ALT)相比,两者降眼压效果相似,但是相对于ALT对小梁网的凝固性损伤,SLT选择性作用于色素性小梁细胞,无凝固性损伤,对小梁网组织轻微破坏,是一种安全且可重复治疗的手段。     

Efficacy of argon laser trabeculoplasty in primary open-angle and pseudoexfoliative glaucoma: Long-term follow-up

A retrospective study was performed to evaluate the long-term efficacy of argon laser trabeculoplasty in 131 patients (148 eyes) with primary open-angle or pseudoexfoliative glaucoma. Success was defined as an intraocular pressure of 22 mm Hg or less, no further glaucoma surgery, and use of comparable or lower-dose topical antiglaucoma treatment. Efficacy of laser trabeculoplasty decreased with time (follow-up, 6 to 120 months). Good results persisted for about 2.5 years in 50% of cases.