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.     

准分子激光屈光性角膜切削术的角膜地形图分析

目的 分析准分子激光屈光性角膜切主后角膜地形图的变化和动态。方法 对接受准分子激光屈光性角膜切削术后随诊３个月的６２例（１２２只眼）和随诊６个月的４９例（９６只眼）的角膜地形图变化和动态进行分析。结果 中央岛型切削是导致术事早期最佳戴镜矫正视力下降１行以上的重要因素，随着时间推移，中央岛型切削逐渐演变其它类型，角膜中央曲率减爱，视力逐步提高。角膜地形图分析，拟似回退指数（ＳｉｍＫ）是反映角膜基质变     

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.     

激光小梁成形术前后对原发性开角型青光眼患者昼夜眼压变化影响

目的 评价选择性激光小梁成形术(Selective laser Trabeculoplasty SLT)对原发性开角型青光眼(primary open-angle glaucoma,POAG)昼夜眼压的影响.方法 POAG患者40例76只眼.倍频Q-开关532nm Nd YAG激光,3ns单脉冲,光斑直径400μm,激光击射下方180°范围小梁组织,能量0.53～0.89mJ,点数60～100点.气动眼压计测量术前及术后12周昼夜眼压,两组数值比较采用配对t检验.结果 术前平均眼压(21.6±2.87)mmHg(1mmHg=0.133KPa),术后平均眼压(18.7±1.36)mmHg,两组比较P＜0.05(t=7.69);手术前后6am点术眼眼压降低最明显,为6.9 mmHg.术前眼压高峰出现在6am,波谷最低在10pm,昼夜眼压波动6.4 mmHg;术后眼压高峰移至12时,最低在22时,昼夜眼压波动3.2 mmHg.结论 SLT治疗原发性开角型青光眼安全、可靠,可有效降低POAG患者的平均眼内压,降低昼夜眼压波动.     

Corneal endothelial cell density and corneal thickness after laser trabeculoplasty]

PURPOSE: The evaluation of the influence of laser trabeculoplasty on the corneal thickness and central endothelial cell density. MATERIAL AND METHODS: Corneal thickness and central endothelial cell density were measured before and 3 months after laser treatment. Patients were divided into 2 groups with different energy applied: 550-800 mW and 850-1100 mW. RESULTS: Differences of corneal thickness and central endothelial cell density were not statistically significant neither within nor between the groups. CONCLUSION: Laser trabeculoplasty performed with energy up to 1100 mW has no influence on corneal thickness and central endothelial cell density.     

选择性激光小梁成形术的研究进展

青光眼是全球第一大不可逆的致盲性眼病,通过药物、激光和手术降低眼压是治疗青光眼的基本方法。选择性激光小梁成形术(SLT)是应用倍频Q开关、波长532 nm的掺钕钇铝石榴石激光,选择性作用于色素性小梁组织达到降低眼压目的。近30年来,SLT在不引起小梁网凝固性损伤的情况下可以降低眼压,已经逐渐成为治疗以原发性开角型青光眼为主的各种类型青光眼的初始治疗或替代治疗方法之一。本文中笔者就SLT的历史沿革、降眼压机制、临床应用、初始治疗、重复治疗、治疗成功的预测因素、并发不良反应、成本效益及健康相关生活质量等方面进行综述。     

选择性激光小梁成形术研究进展

激光治疗是青光眼治疗的重要手段之一。选择性激光小梁成形术（SLT）选择性作用于小梁网的色素细胞,避免了对周边组织的损害,同时可起到一定程度的降眼压作用,其机制复杂,目前尚不完全明确。相关研究显示,对于开角型青光眼,SLT具有与氩激光小梁成形术（ALT）以及药物治疗相似的效果,在部分复杂病例及闭角型青光眼中也显示了一定的降眼压作用,术后反应较轻,且可以重复操作,将会越来越受到重视。就SLT的原理、临床应用进展及其并发症等进行综述。     

Corneal endothelial changes following a single session of selective laser trabeculoplasty for pseudoexfoliative glaucoma

Purpose

To evaluate corneal endothelial cell parameters after a single session of selective laser trabeculoplasty (SLT) in pseudoexfoliative glaucoma (PEG) patients.

Methods

Corneal endothelial cell parameters of 18 PEG patients were compared with 18 healthy subjects following SLT treatment. All patients underwent SLT treatment to 180 degrees of inferior trabecular meshwork. Corneal measurements were performed using specular microscopy (Noncon Robo SP8000, Konan Medical, Hyogo, Japan). Endothelial cell density (ECD), hexagonal cell ratio (HEX), coefficient of variation (CV) of the corneal endothelial cell layer and central corneal thickness of the patients were measured at each visit.

Results

There was a statistically significant decrease in ECD (p = 0.004) and a statistically significant increase in CV (p = 0.041) at superior cornea 1 week after SLT. They returned to pre-SLT values at 1 month. One hour post-SLT HEX of inferior cornea was statistically significantly reduced (p = 0.01). At central cornea, there was a significant increase in HEX after 1 week (p = 0.001). Post-SLT IOP showed a significant positive correlation with CV and significant negative correlation with HEX at superior and inferior cornea. There was no correlation between total laser energy used and endothelial cell parameters.

Conclusion

Effect of a single session of SLT on corneal endothelium of PEG patients appears to be transient, and superior cornea was more affected than central and inferior cornea. All parameters returned to pre-SLT values at 1 month after treatment.

     

Corneal endothelial cell density after trabeculoplasty

Central corneal endothelial photographs were taken with a specular microscope. The cell density was calculated with a computerized image analyzer. No difference between the treated and control eyes could be found. The laser energy level delivered in trabeculoplasty seems to be too small to induce any permanent changes in the endothelial cells.     

Inflammation assessment after selective laser trabeculoplasty (SLT) treatment

Purpose: Selective laser trabeculoplasty (SLT) appears to be a safe and effective method to lower intraocular pressure (IOP). The exact mechanism of action for reducing IOP and inflammation levels is not known. The aim of this study was to assess inflammation after SLT treatment. Methods: Forty patients (80 eyes) were included in the study. Inclusion criteria: Glaucoma (pigmentary and pseudoexfoliative glaucoma)/ocular hypertension patients that will be treated with SLT in just one eye, both with and without eye‐drops. Exclusion criteria: patients suffering from ocular or systemic inflammatory diseases are treated with cortisone or immunosuppressive drugs. Inflammation was measured in two different ways: (i) clinically with a slit lamp and classified 0–4; (ii) objectively with a ‘Laser flare meter (Kowa FM 500)’. Measurements were taken before SLT, 2 hr, 1 week and 1 month after SLT treatment, both eyes were evaluated. IOP was also checked in the same way. SLT treatment was performed in 90°. Results: Inflammation before and after SLT showed no significant difference measured clinically with slit lamp and objectively with the laser flare meter among the groups. No inflammation or IOP reduction was found in the untreated eyes. No IOP spikes after SLT treatment were found. Conclusion: Selective laser trabeculoplasty treatment seems not to induce inflammation in the anterior chamber when 90° was treated. SLT effectively and safely lowers IOP and might be considered as primary therapy.     

Peripheral anterior synechiae after selective laser trabeculoplasty among Chinese patients

Graefe's Archive for Clinical and Experimental Ophthalmology - Peripheral anterior synechiae (PAS) have been reported as a complication after argon laser trabeculoplasty, but rarely reported...     

Quality of life in glaucoma patients after selective laser trabeculoplasty

AIM: To compare quality of life and treatment satisfaction between patients who had selective laser trabeculoplasty (SLT) and those on medication. METHODS: A prospective clinical trial on 143 glaucoma patients that received SLT and a control group that continued using anti glaucoma medication was conducted. Tear break-up time (BUT), punctuate keratitis, need for help, use of artificial tears and the treatment satisfaction survey of intraocular pressure (IOP) were measured at baseline, 6 and 12mo. RESULTS: SLT was able to reduce the mean number of medications needed from 1.56±0.81 to 0.42±0.66 at six months and to 0.33±0.69 at one year. Punctuate keratitis was observed significantly less often (12.24%) after SLT than before (35.94%; P=0.03). Use of artificial tears and BUT did not change significantly after SLT (P>0.05). At baseline, patients in the SLT group were significantly less convinced of medication effectiveness (P=0.006) and complained more about side effects (P=0.003). After SLT, these patients had significantly more confidence in their therapy (P<0.001), showed less side effects (P=0.006), complained less about changes in appearance of the eyes (P=0.003) and were less inconvenienced by the use of eye drops (P<0.001). CONCLUSION: SLT is able to improve treatment-related quality of life in glaucoma patients.     

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.

Clinical results of selective laser trabeculoplasty

PURPOSE: Selective laser trabeculoplasty (SLT) is a new technique aimed to developed to impact pigmented trabecular cells selectively. Compared with ordinary argon laser trabeculoplasty, it is expected to have fewer complications with more efficacy for open-angle glaucoma. In this study we performed SLT on 17 eyes of 10 patients with primary open-angle glaucoma and 1 eye with capsular glaucoma. METHODS: Follow-up period was up to 10 months. Average energy irrachieted was 28.14 mJ (0.47 mJ x 59 spots) against pigmented trabecular band over the half circumference of anterior chamber angle. RESULTS: Preoperative mean intraocular pressure (IOP) was 22.8 mmHg and postoperative mean IOP was decreased significantly to 8.6, 17.3, and 16.1 mmHg at 1, 3, and 6 months after treatment, respectively. The average maximum IOP reduction was 8.8 (3-18) mmHg after SLT. Among 11 eyes showing transient IOP elevation, 6 eyes had an elevation of more than 5 mmHg. No remarkable postoperative complications were noted. CONCLUSION: SLT is a safe and effective modality for the treatment of open-angle glaucoma such as primary open-angle glaucoma (POAG) and capsular glaucoma.     

Comparison of the morphologic changes after selective laser trabeculoplasty and argon laser trabeculoplasty in human eye bank eyes

OBJECTIVE: To compare the histopathologic changes in the human trabecular meshwork (TM) after argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT) with a Q-switched, frequency-doubled, neodymium:yttrium-aluminum-garnet laser. DESIGN: Human "in vitro" experimental study. TISSUE AND CONTROLS: Eight human autopsy eyes were obtained within 18 hours of death from persons aged 71 to 78 years. METHODS: The anterior segment of autopsy eyes was isolated, and one half of each trabecular meshwork underwent SLT and the other half ALT. Specimens were evaluated with scanning and transmission electron microscopy. MAIN OUTCOME MEASURES: Structural changes in the TM were detected by scanning electron microscopy, and cellular or intracellular changes were seen with transmission electron microscopy. RESULTS: Evaluation of the TM after ALT revealed crater formation in the uveal meshwork at the junction of the pigmented and nonpigmented TM. Coagulative damage was evident at the base and along the edge of craters, with disruption of the collagen beams, fibrinous exudate, lysis of endothelial cells, and nuclear and cytoplasmic debris. Evaluation of the TM after SLT revealed no evidence of coagulative damage or disruption of the corneoscleral or uveal trabecular beam structure. Minimal evidence of mechanical damage was present after SLT, and the only ultrastructural evidence of laser tissue interaction was cracking of intracytoplasmic pigment granules and disruption of trabecular endothelial cells. CONCLUSIONS: SLT applied "in vitro" to the TM of human eye bank eyes seemed to cause no coagulative damage and less structural damage to the human TM when compared with ALT and, therefore, may be a safer and more repeatable procedure.