Selective laser trabeculoplasty: current perspectives

Circumferential (360°) trabeculotomy for steroid-induced glaucoma in adults

PURPOSE

To evaluate the safety and efficacy of 360° circumferential trabeculotomy (TO) for steroid induced glaucoma (SIG) of short duration.

METHODS

Retrospective analysis of surgical results of 46 eyes of 35 patients undergoing microcatheter-assisted TO. All eyes had high intraocular pressure for at most about 3 years due to steroid use. Follow-up was between 2.63 and 47.9 months (mean 23.9, median 25.6).

RESULTS

Intraocular pressure (IOP) before surgery was 30.8 ± 8.3 mm Hg, with 3.8 ± 1.0 pressure-lowering medications. After 1 to 2 years, mean IOP was 11.2 ± 2.6 mm Hg (n = 28); mean number of IOP-lowering medications was 0.9 ± 1.3. At their last follow-up, 45 eyes had an IOP < 21 mm Hg, and 39 eyes had an IOP < 18 mm Hg with or without medication. After 2 years, the estimated probability of having an IOP below 18 mm Hg (with or without medication) was 85 ± 6%, and the estimated probability of not using medication was 56 ± 7%. Steroid response was no longer present in all eyes receiving steroids after surgery. Minor complications consisted of hyphema, transient hypotony, or hypertony. One eye proceeded to receiving a glaucoma drainage implant.

CONCLUSION

TO is particularly effective in SIG with relative short duration. This concurs with the pathophysiology of the outflow system. This procedure seems particularly suited for eyes for which target pressures in the mid-teens are acceptable, particularly when chronic use of steroids is necessary .

Selective laser trabeculoplasty as adjunctive treatment for open-angle glaucoma vs following incisional glaucoma surgery in Chinese eyes

BACKGROUND

Selective laser trabeculoplasty (SLT) is a relatively safe and effective therapy in lowering intraocular pressures (IOP) for glaucoma.

AIM

To study the long-term effects of SLT on IOP and number of glaucoma medications used in Chinese eyes.

METHODS

This is a retrospective study in which 75 eyes of 70 patients with open-angle glaucoma (OAG, n =36) and eyes with prior glaucoma surgery (PGS, n =39) were included. Changes in mean IOP and number of glaucoma medications used evaluated at 1 d, 1 wk, 1 mo, 3 mo, 6 mo, 12 mo, and 36 mo after laser treatment.

RESULTS

All patients (33 male, 37 female) were Chinese. The mean age was 44.34 ± 16.14 years. Mean pre-SLT IOP was 22.75 ± 2.08 mmHg in OAG and 22.52 ± 2.62 mmHg in PGS. Mean IOP was significantly reduced 1 d, 1 wk, 1 mo and 3 mo after laser treatment (P < 0.05, respectively). Whereas, there were no significant differences between baseline and SLT treated groups at the 6^th month both in OAG (P = 0.347, P > 0.05) and in PGS (P = 0.309, P > 0.05). Six months after SLT treatment, some patients received retreatment of SLT or were given more topical IOP-lowering medication to control the IOP. By the end of our study, the average IOP decreased to 20.73 ± 1.82 mmHg in OAG and 20.49 ± 1.53 mmHg in PGS groups. The number of glaucoma medications used was significantly reduced until the end of 3 years compared to baseline.

CONCLUSION

SLT could reduce IOP as adjunctive treatment both in OAG and PGS groups. SLT significantly reduced the number of glaucoma medications used 3-years following treatment in glaucoma patients.

Comparison of success rate and intraocular pressure spikes between selective laser trabeculoplasty and micropulse laser trabeculoplasty in African American and Hispanic patients

AIM

To examine the efficacy and safety of micropulse laser trabeculoplasty (MLT) versus selective laser trabeculoplasty (SLT) in a large cohort of primarily African American and Hispanic patients.

METHODS

A single center retrospective comparative cohort review conducted at Cook County Health facilities that included patients with a diagnosis of open angle glaucoma or ocular hypertension who received an SLT or MLT procedure between January 2017 and May 2021.

RESULTS

Totally 131 eyes of 99 patients were analyzed. The 77 eyes received SLT and 54 received MLT. Seven out of 77 eyes in the SLT group (9.1%) and 1 out of 54 eyes in the MLT group (1.9%) had an IOP spike (defined as > 5 mm Hg) at either 1h or 1wk after procedure (P=0.05, Chi-squared test with Haldane-Anscombe correction). The procedure failure rate at one year was 50% for SLT and 48% for MLT (P=0.31).

CONCLUSION

MLT has a significantly lower incidence of pressure spikes and a similar treatment failure rate at 1-year post-procedure, demonstrating that it is a reasonable alternative compared to SLT.

The place of endoscopic laser cyclodestruction in the system of microinvasive glaucoma surgery

Glaucoma is one of the leading causes of irreversible blindness in the world. Reducing intraocular pressure is the only way to slow down the progression of glaucomatous optic neuropathy. Minimally invasive glaucoma surgery aims to provide a safer way of reduction of intraocular pressure than traditional methods, and at the same time it is capable to reduce dependence on antihypertensive therapy. Cyclodestructive high-precision method of reducing the production of aquоeus humor occupies a confident position among modern minimally invasive glaucoma surgery methods. The data obtained as a result of studying the literature confirm our idea on the endoscopic laser cyclodestruction method as a minimally invasive, safe, reliable antiglaucomatous component of the combined surgical treatment of cataract and glaucoma.

Femtosecond Laser Trabeculotomy in Perfused Human Cadaver Anterior Segments: A Novel, Noninvasive Approach to Glaucoma Treatment

Purpose

The purpose of this study was to investigate femtosecond laser trabeculotomy (FLT) in a clinically relevant manner (i.e., delivering the surgical laser beam through the cornea of the intact, human anterior segment to create channels from the anterior chamber into the Schlemm's canal) and to investigate the effect of this treatment on intraocular pressure in perfused human anterior segments.

Methods

Perfused human anterior segments (15 eyes) received either FLT treatment (n = 8) or a sham-treatment (n = 7). Intraocular pressure (IOP) in the perfused samples was recorded before and after treatment. Spectral domain optical coherence tomography, second harmonic generation imaging, and transmission electron microscopy were used to investigate the FLT channels.

Results

The FLT group (n = 7, 1 eye excluded) had a statistically significant reduction in mean IOP of 20.2% from baseline after treatment (5.06 ± 1.46 mm Hg to 4.04 ± 1.63 mm Hg; P < 0.0005), whereas the control group (n = 7) remained statistically unchanged (7.72 ± 3.45 mm Hg to 7.78 ± 3.51 mm Hg; P < 0.71). Imaging confirmed that the channels traversed the entire trabecular meshwork into the Schlemm's canal.

Conclusions

This study has provided the first direct evidence supporting the feasibility of clinically applicable, noninvasive femtosecond laser trabeculotomy for the treatment of glaucoma. Various imaging modalities revealed minimal collateral damage to adjacent issues.

Translational Relevance

This work demonstrates noninvasive femtosecond laser trabeculotomy in a laboratory setting that is clinically relevant.

Efficacy of Selective Laser Trabeculoplasty after iStent Implantation in Primary Open-Angle Glaucoma

iStent implantation is thought to augment the trabecular outflow channel in the anterior segment of the eye. We hypothesized that iStent with subsequent selective laser trabeculoplasty (SLT) would better control the intraocular pressure (IOP) compared to standalone SLT in patients with primary open-angle glaucoma (POAG). We, therefore, determined if the presence of an iStent combined with SLT was statistically associated with IOP lowering compared to standalone SLT. Through retrospective electronic medical record review, records of 824 eyes from 440 patients who received primary SLT without a history of iStent were considered. Additionally, 42 eyes from 28 patients who received SLT after combined phacoemulsification and iStent implantation that failed to control intraocular pressure (IOP) and/or the progression of the disease were retrospectively reviewed. IOP and number of medications, which were tracked in each patient for up to 12 months post laser, were also examined. Successful outcome was defined as a statistically significant reduction in IOP or number of medications at 6 months. As defined in univariate analysis (p ≤ 0.01), multivariate analysis included iStent, age, sex, race, and initial IOP as variables. IOP reduction was statistically associated with patients pre-SLT IOP (p < 0.001) but not with patients with iStent (p = 0.222). Medication reduction was statistically associated with the pre-SLT number of medications (p < 0.001) and iStent (p < 0.001). In eyes that received SLT, iStent was not statistically associated with a greater reduction in IOP compared to controls, but was associated with a higher reduction in the overall number of medications used 6 months after receiving SLT. The work presented should guide clinicians to consider SLT as an effective therapy after iStent implantation, in terms of glaucoma medication reduction in iStent patients, but clinicians should know that the presence of an iStent does not necessarily make subsequent SLT more effective at lowering IOP.

iStent for Adults With Glaucoma: A Health Technology Assessment

BACKGROUND

Glaucoma is a condition that causes progressive damage to the optic nerve, which can lead to visual impairment and potentially to irreversible blindness. The iStent and iStent inject are devices implanted in the eye during a type of minimally invasive glaucoma surgery (MIGS) to reduce intraocular pressure by increasing trabecular outflow by bypassing the trabecular meshwork. We summarized two health technology assessments and additional recent publications that evaluated iStent for people with glaucoma, including effectiveness, safety, cost-effectiveness, the budget impact of publicly funding iStent, and patient preferences and values.

METHODS

We summarized two health technology assessments recently completed in Canada. In addition, we summarized new evidence we identified through expert consultation and scoping of the literature. We reported the quality of the body of clinical evidence as reported by the included health technology assessments, according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria.

RESULTS

Comparing iStent with pharmacotherapy, there may be no difference in comparative clinical effectiveness (GRADE: Very low to Low). There was uncertainty around the comparative clinical effectiveness of iStent compared with filtration surgery and of iStent plus cataract surgery compared with a different MIGS procedure plus cataract surgery (GRADE: Very low). iStent with cataract surgery may improve comparative clinical effectiveness (reduced intraocular pressure and number of medications) compared with cataract surgery alone (GRADE: Low).iStent may be cost-effective compared with pharmacotherapy (incremental cost-effectiveness ratios [ICER]: $14,120-$25,596/quality-adjusted life-year [QALY]; 60%-76% and 65%-100% of iterations cost-effective at willingness-to-pay values of $50,000/QALY and $100,000/QALY, respectively). iStent with cataract surgery may not be cost-effective compared with cataract surgery alone (ICERs: $108,934-$112,380/QALY; 17%-46% and 46%-68% of iterations cost-effective at willingness-to-pay values of $50,000/QALY and $100,000/QALY, respectively). iStent may not be cost-effective compared with filtration surgery (iStent was less effective and more expensive than filtration surgery). These estimates are influenced by the long-term effectiveness of iStent.The iStent device costs approximately $1,250 (for two iStent or iStent inject devices). Based on a recent analysis by Quebec's Institut national d'excellence en santé et en services sociaux (INESSS) and our previous analysis on MIGS, publicly funding iStent may reduce some spending on glaucoma medication but, overall, iStent is likely to lead to additional costs for the public health care system. In Ontario, publicly funding MIGS over 5 years is estimated to cost a total of $40 million if uptake is slow (25,000 people) and $199 million, if uptake is fast (100,000 people). In Quebec, publicly funding iStent over 3 years is estimated to cost a total of $29 million (15,000 people).People with glaucoma with whom we spoke reported that pharmacotherapy can be challenging and that they relied on trust in their physician to determine if surgery was necessary to avoid potential consequences of glaucoma, such as blindness. Those who received MIGS procedures found it beneficial, with minimal side effects and recovery time. However, they were often unaware what type of MIGS procedure they received, so they could not specifically comment on iStent.

CONCLUSIONS

We are uncertain about the comparative clinical effectiveness of iStent compared with filtration surgery, as well as iStent combined with cataract surgery versus other MIGS procedures combined with cataract surgery. There may be no difference in the comparative clinical effectiveness of iStent compared with pharmacotherapy. iStent combined with cataract surgery may improve clinical effectiveness (mainly intraocular pressure and number of medications) when compared with cataract surgery alone.In some instances, iStent may be cost-effective (i.e., when compared with pharmacotherapy) but in other instances it may not be cost-effective (i.e., when iStent combined with cataract surgery is compared with cataract surgery alone or when iStent is compared with filtration surgery). Publicly funding iStent may reduce some spending on pharmacotherapy but, overall, is likely to lead to additional costs for the public health system. People with glaucoma reported that pharmacotherapy adherence could be challenging, and that avoiding blindness was their main priority for treatment. Experiences with MIGS procedures were positive, although patients were unable to comment on iStent specifically.

Selective Laser Trabeculoplasty Versus MIGS: Forgotten Art or First-Step Procedure in Selected Patients with Open-Angle Glaucoma

Introduction

To evaluate the long-term effect on intraocular pressure (IOP) and glaucoma medication of selective laser trabeculoplasty (SLT) compared to minimally invasive glaucoma surgery (MIGS) in primary open-angle glaucoma (POAG) and its potential in clinical practice.

Methods

A total of 342 consecutive patients (stand-alone procedures) were included. One hundred and five patients underwent SLT treatment (360° SLT, 95–105 spots, Trabeculas SLT ARCLaser, Nürnberg, DE), 107 patients had an ab interno-derived trabeculotomy (Trabectome^®, NeoMedix, Tustin, USA), and 130 patients received iStent inject^® implantation (2 implants-Glaukos, CA, USA). IOP and glaucoma therapy were evaluated preoperatively, 1 day, 6 weeks, 3 months, 6 months, and 1, 2, and 3 years postoperatively. Statistical analysis was performed using a regression model and propensity matching score (reduced cohort number) using SPSS v20.0. Kaplan–Meier analysis was included using the following six criteria: criterion A (IOP ≤ 21 mmHg with or without medication, qualified success), criterion B (IOP ≤ 18 mmHg with or without medication, qualified success), criterion C (IOP ≤ 21 mmHg without medication, complete success), criterion D (IOP ≤ 18 mmHg without medication, complete success), criterion E (IOP ≤ 21 mmHg and IOP reduction > 20% after therapy), and criterion F (IOP ≤ 18 mmHg and IOP reduction > 20% after therapy).

Results

In the matched cohort, the SLT cohort showed an IOP reduction of 31.2% from 19.9 ± 2.3 to 13.7 ± 2.7 mmHg (p < 0.001) 3 years postoperatively; in Trabectome^® IOP decreased by 31.4% from 20.5 ± 1.3 to 13.8 ± 2.0 mmHg (p < 0.001) and in iStent inject^® by 29.9% from 19.5 ± 2.0 to 13.8 ± 2.7 mmHg (p < 0.001). Trabectome^® and iStent inject^® could not demonstrate a significant reduction in glaucoma therapy (Trabectome^®p = 0.138, iStent inject^®p = 0.612); a significant drop was noted in SLT (2.2 ± 1.2 to 1.7 ± 1.2, p = 0.046). SLT and MIGS achieved good to moderate survival rates using criterion A (93.3% SLT, 79.7% Trabectome^®, 77.6% iStent inject^®) and criterion B (74.5% SLT, 48.0% Trabectome^®, 56.2% iStent inject^®). As expected, low survival rates were obtained with non-filtering procedures: criterion C 11.1% in SLT, 6.5% in Trabectome^®, 7.0% in iStent inject^® and criterion D 3.0% in SLT, 4.3% in Trabectome^®, 3.7% in iStent inject^® in 3-year follow-up.

Conclusion

The SLT is a low-complication and effective method for reducing pressure in mild to moderate POAG. SLT is suitable as an initial procedure when setting up a step scheme; MIGS is the treatment of choice as a follow-up for mild to moderate forms of glaucoma and accepted topical therapy. Ethic approval had been given by the Ethikkommission Charité – Universitätsmedizin Berlin, EA4/047/20—retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-021-00347-0.

Outcome After Selective Laser Trabeculoplasty for Glaucoma Treatment in a Thai Population

Purpose

The study aimed to evaluate the efficacy and predictive factors of success after selective laser trabeculoplasty (SLT) for treating various types of open-angle glaucoma in a Thai population.

Design

The study employed a retrospective cohort design.

Materials and Methods

The study retrospectively recruited Thai subjects diagnosed with open-angle glaucoma receiving first time selective laser trabeculoplasty. Primary open-angle glaucoma (POAG), ocular hypertension (OHT) and other types of open-angle glaucoma were included. Reduced intraocular pressure (IOP) of 20% or decreased number of antiglaucoma drugs usage after SLT was defined as success. Various parameters were analyzed for association with SLT success.

Results

Ninety-six eyes were recruited in the study. Mean pre- and postSLT IOP were 19.31±3.59 and 15.04±3.13 mmHg, respectively. IOP decreased significantly in all follow-up visits (p<0.001). Overall, 59.4% met the treatment endpoint. More than 10% postSLT IOP elevation at 1 hour was the only covariate positively associated with SLT success in both univariate (odds ratio (OR) = 1.042, p = 0.037) and multivariate analyses (OR = 1.040, p = 0.046). Underlying hypertension and preSLT IOP were negatively associated with SLT success in both univariate (OR = 0.970, p = 0.026, OR = 0.955, p < 0.001) and multivariate analysis (OR = 0.970, p = 0.026, OR = 0.991, p < 0.001).

Conclusion

IOP significantly decreased as well as the number of antiglaucoma drugs needed after SLT. More than 10% postSLT IOP elevation at 1 hour was a positive predictor whereas systemic hypertension and preSLT IOP were negative predictors of SLT success.

Responsiveness to ripasudil may be a potential outcome marker for selective laser trabeculoplasty in patients with primary open-angle glaucoma

We examined responsiveness to ripasudil as a potential factor for predicting the effect of selective laser trabeculoplasty (SLT) when performed for primary open-angle glaucoma (POAG). A total of 70 eyes with no history of glaucoma surgery underwent SLT between January 2015 and June 2019. Patients were divided into two groups, with an intraocular pressure (IOP) decrease of 15% or more due to ripasudil administration before SLT defined as the effective group, while an IOP decrease of less than 15% was defined as the non-effective group. Kaplan–Meier survival analysis was performed. A Cox proportional hazards model assessed the influence of baseline factors on the success. Of the 70 eyes evaluated, treatments were effective in 22 and non-effective in 48. Postoperatively, both groups exhibited IOP reductions for up to 24 months. Success ratios at 12 and 24 months after SLT were 43.5% and 18.5% in the effective versus 24.9% and 9.3% in the non-effective group, which were significantly higher in the effective group (P = 0.03). Presence of a ripasudil effective eye (P = 0.03) was associated with treatment success. Responsiveness to ripasudil may be useful in predicting the therapeutic effect of SLT.

Photoablative cosmetic iridoplasty: effective, safe, and predictable-eye color change in 1176 eyes

Purpose

To evaluate photoablative cosmetic iridoplasty (PCI), and its efficacy, safety, predictability, and satisfaction with the 532 nm Crystal Q-switched Nd: Yag laser, with 3–4 ns pulses, for depigmentation of the anterior epithelium of the iris in cases of heterochromia, nevus, or cosmetic indications (eye color change).

Design

Prospective clinical study on efficacy, safety, predictability, and satisfaction.

Method

The selection of patients was carried out in healthy individuals, over 18 years of age, with iris heterochromia (congenital-7% or acquired, secondary to topical medication-1%, trauma-0.5% or surgery-0.25%), nevus-0.25% and cosmetic cases-91%. Data were collected independently by assistant optometrists and classified in database. Excel statistical program was used to perform a general descriptive study, calculation of correlation factors, and statistical significance analysis between quantitative variables (Student T Test). PCI was performed in 1176 eyes of 588 patients. The procedures were planned in 2–3 phases of 4 consecutive sessions spaced 4–6 months apart. The IRÎZ^® (Eyecos^®) scanner was used to evaluate the cases, with photography, optical coherence tomography, and pneumotonography modules, along with the following software programs: Predictor^®, Simulator^® 3D, Analyzer^® and Planner^® (Eyecos^®).

Results

This study began in 2012, so far 9 years of follow-up, to compare and choose the most suitable among 4 types of lasers to perform cosmetic iridoplasty. Finally, after 5 years, the Crystal Q-switched Nd: Yag at double frequency (532 nm) with 3–4 ns pulses demonstrated the highest efficacy, safety and predictability, so since early 2017 only this equipment has been used. Significant differences were found after 5-year follow-up between 1064, 532, 577 and 532/3–4 ns p = 0.09172, 0.06377 and 0.10183. From 9 January 2017 to 28 February 2020, 1176 eyes have been treated in 588 patients, with a mean age of 33.7 years (SD = 9.68 years, range = 18–70 years). 46.2% were male, and 53.7% were female. The efficacy, as quantified with the Analyzer^® comparison software, was nearly 87–95%. There were no significant differences in corrected vision (9 years total follow-up p = 0.78235; last 4 years FU p = 0.99999) and ocular pressure (9 years total FU p = 0.68251; last 4 years FU p = 0.63204) before and after the procedure. The only notable complications (25%) were delayed and brief iritis, which were self-limited with routine topical treatment. The predictability was 80–90%. In the lightest-colored eyes, turquoise blue colors were obtained as a rule, in varying brightness; and in the darkest ones, gray blue tones of varying lightness. The patients’ subjective satisfaction at the end of treatment was 95%.

Conclusion

After 9 years of uninterrupted follow-up, PCI has demonstrated a high effectiveness to selectively depigment superficial melanin of iris, with a high predictability and patient satisfaction, without remarkable long-term complications. Only for a week, appropriate pre- and postoperative medication was necessary to guarantee the absence of discomfort, thus confirming security. PCI is effective, safe, and predictable for the treatment of pigmentary disorders in the iris and for the elective cosmetic indications in eye color change.

Real-world efficacy of the Hydrus microstent in Black and Afro-Latinx patients with glaucoma: a retrospective study

Purpose:

The purpose was to determine the real-world efficacy of phacoemulsification cataract surgery and Hydrus microstent in Black and Afro-Latinx patients with glaucoma.

Methods:

A retrospective noncomparative single-center study of 76 Black and Afro-Latinx patients with glaucoma who underwent phacoemulsification cataract surgery and Hydrus microstent placement for treatment of glaucoma at single practice. Investigated parameters were intraocular pressure (IOP), number of medications, mean deviation on visual field test, and visual acuity. Patients were also subgrouped into mild, moderate, and advance glaucoma for further analysis.

Results:

We reviewed a total of 76 patients who had 6 months of follow up in the study. The mean number of medications decreased significantly from 2.6 ± 1.5 preoperatively to 0.72 ± 1.4 in 6 months (p < 0.0010), while IOP decreased from 14.7 ± 3.7 to 13.9 ± 4.3 (p = 0.25). At 6 months, 55 patients (74%) of all patients were medication free (n = 27, 84.4% mild glaucoma; n = 17, 70.8% moderate glaucoma; n = 10, 50% advance glaucoma). There was significant improvement in visual acuity (p < 0.00010) and stabilization of mean deviation on visual field test (baseline −9.2; 6 months −9.1; p = 0.22). The most common adverse effect was a transient IOP spike and transient corneal edema (n = 6, 7.9%; n = 6, 7.9%, respectively) with spontaneous resolution in all cases. No sight-threatening complications were reported at 6 months.

Conclusion/clinical relevance:

This 6-month retrospective study demonstrated the efficacy of phacoemulsification cataract surgery and Hydrus microstent in reducing the medication burden while maintaining lower IOP in Black and Afro-Latinx patients with glaucoma.

Combination microinvasive glaucoma surgery: 23-gauge cystotome goniotomy and intra-scleral ciliary sulcus suprachoroidal microtube surgery in refractory and severe glaucoma: A case series

The purpose of this study is to present the efficacy of combined goniotomy and intra-scleral ciliary sulcus suprachoroidal microtube insertion surgery in five patients with refractory and severe glaucoma. This Single-center, case series of five (5) Black and Afro-Latino patients with refractory and severe glaucoma who underwent combination microinvasive glaucoma surgery; 23-gauge goniotomy and intra-scleral ciliary sulcus suprachoroidal microtube insertion. Patients who underwent the above procedure with 6 months follow-up were included. Investigated parameters were intraocular pressure (IOP), number of medications, visual field findings, and visual acuity. Five patients with moderate to severe refractory glaucoma who had undergone 23-gauge cystotome goniotomy and ciliary sulcus suprachoroidal microtube had a reduction of IOP by 32% (mean pre-op and post-op 16.6 mmHg and 11 mmHg, respectively) and a reduction of ocular medications by 61.5% (mean pre-op and post-op of 5.2 and 2.4, respectively). All patients had either stabilization or improvement of their visual fields. Four of the five patients also showed an improvement in visual acuity. This novel approach of combined 23-gauge goniotomy and intra-scleral ciliary sulcus suprachoroidal microtube insertion surgery is safe and is an affordably effective means of managing patients with moderate to advanced refractory glaucoma, leading to a reduction in IOP and the number of medications with no serious adverse effects.

Intraocular pressure-lowering effects of ripasudil, a rho-kinase inhibitor, and selective laser trabeculoplasty as adjuvant therapy in patients with uncontrolled glaucoma

OBJECTIVES

To compare the intraocular pressure (IOP)-lowering effects of ripasudil, a rho-kinase inhibitor, and selective laser trabeculoplasty (SLT) as adjuvant therapy in Japanese glaucoma patients and to identify the factors associated with treatment success.

METHODS

We performed a retrospective medical chart review of patients with glaucoma who received ripasudil or SLT as an adjuvant therapy. We collected data on 65 eyes (65 patients) with primary open-angle glaucoma, normal-tension glaucoma, or exfoliation glaucoma with at least 12 months of follow-up. IOP and number of glaucoma medications at 0, 1, 3, 6, 9, and 12 months were compared between and within groups. A repeated-measures mixed model was used to perform statistical analysis. We also investigated factors associated with treatment success, which was defined as ≥ 20% reduction in IOP at all follow-up periods, using univariate and multivariate logistic regression analysis.

RESULTS

Significant IOP reduction was observed at all time-points after treatment in the ripasudil group (n = 33) and in the SLT group (n = 32), with no statistically significant difference between the groups before or after treatment. Patients in the SLT group used more anti-glaucoma medications before treatment, but fewer during follow-up, than those in the ripasudil group. Regardless of treatment, higher baseline IOP was associated with treatment success [crude odds ratio: 1.21 (95% confidence interval: 1.06-1.38), adjusted odds ratio: 1.37 (95% confidence interval: 1.06-1.77)].

CONCLUSIONS

Adjuvant SLT or ripasudil in patients with inadequately controlled glaucoma both reduced IOP to a similar degree, but SLT contributed to reducing the number of medications used.

Selective laser trabeculoplasty versus drops for newly diagnosed ocular hypertension and glaucoma: the LiGHT RCT

BACKGROUND

Newly diagnosed open-angle glaucoma (OAG) and ocular hypertension (OHT) are habitually treated with intraocular pressure (IOP)-lowering eyedrops. Selective laser trabeculoplasty (SLT) is a safe alternative to drops and is rarely used as first-line treatment.

OBJECTIVES

To compare health-related quality of life (HRQoL) in newly diagnosed, treatment-naive patients with OAG or OHT, treated with two treatment pathways: topical IOP-lowering medication from the outset (Medicine-1st) or primary SLT followed by topical medications as required (Laser-1st). We also compared the clinical effectiveness and cost-effectiveness of the two pathways.

DESIGN

A 36-month pragmatic, unmasked, multicentre randomised controlled trial.

SETTINGS

Six collaborating specialist glaucoma clinics across the UK.

PARTICIPANTS

Newly diagnosed patients with OAG or OHT in one or both eyes who were aged ≥ 18 years and able to provide informed consent and read and understand English. Patients needed to qualify for treatment, be able to perform a reliable visual field (VF) test and have visual acuity of at least 6 out of 36 in the study eye. Patients with VF loss mean deviation worse than -12 dB in the better eye or -15 dB in the worse eye were excluded. Patients were also excluded if they had congenital, early childhood or secondary glaucoma or ocular comorbidities; if they had any previous ocular surgery except phacoemulsification, at least 1 year prior to recruitment or any active treatment for ophthalmic conditions; if they were pregnant; or if they were unable to use topical medical therapy or had contraindications to SLT.

INTERVENTIONS

SLT according to a predefined protocol compared with IOP-lowering eyedrops, as per national guidelines.

MAIN OUTCOME MEASURES

The primary outcome was HRQoL at 3 years [as measured using the EuroQol-5 Dimensions, five-level version (EQ-5D-5L) questionnaire]. Secondary outcomes were cost and cost-effectiveness, disease-specific HRQoL, clinical effectiveness and safety.

RESULTS

Of the 718 patients enrolled, 356 were randomised to Laser-1st (initial SLT followed by routine medical treatment) and 362 to Medicine-1st (routine medical treatment only). A total of 652 (91%) patients returned the primary outcome questionnaire at 36 months. The EQ-5D-5L score was not significantly different between the two arms [adjusted mean difference (Laser-1st - Medicine-1st) 0.01, 95% confidence interval (CI) -0.01 to 0.03; p = 0.23] at 36 months. Over 36 months, the proportion of visits at which IOP was within the target range was higher in the Laser-1st arm (93.0%, 95% CI 91.9% to 94.0%) than in the Medicine-1st arm (91.3%, 95% CI 89.9% to 92.5%), with IOP-lowering glaucoma surgery required in 0 and 11 patients, respectively. There was a 97% probability of Laser-1st being more cost-effective than Medicine-1st for the NHS, at a willingness to pay for a quality-adjusted life-year of £20,000, with a reduction in ophthalmology costs of £458 per patient (95% of bootstrap iterations between -£585 and -£345).

LIMITATION

An unmasked design, although a limitation, was essential to capture any treatment effects on patients' perception. The EQ-5D-5L questionnaire is a generic tool used in multiple settings and may not have been the most sensitive tool to investigate HRQoL.

CONCLUSIONS

Compared with medication, SLT provided a stable, drop-free IOP control to 74.2% of patients for at least 3 years, with a reduced need for surgery, lower cost and comparable HRQoL. Based on the evidence, SLT seems to be the most cost-effective first-line treatment option for OAG and OHT, also providing better clinical outcomes.

FUTURE WORK

Longitudinal research into the clinical efficacy of SLT as a first-line treatment will specify the long-term differences of disease progression, treatment intensity and ocular surgery rates between the two pathways.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN32038223.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 31. See the NIHR Journals Library website for further project information.

Minimally Invasive Surgery in Mild-to-Moderate Glaucoma Patients in Italy: Is It Time to Change?

Medical therapy is the first treatment choice for most patients with glaucoma; however, in a relevant proportion of patients, intraocular pressure (IOP) reduction is achieved with multi-therapy and/or high therapeutic doses. Conventional surgery is the standard alternative to medical therapy when this is not effective or not tolerated. Recently, selective laser trabeculoplasty (SLT) has been advocated as first-line therapy, and "minimally invasive glaucoma surgery" (MIGS) has been developed as safer and less traumatic surgical intervention for patients with glaucoma. Schlemm's canal surgery has emerged as one of the approaches with the most favorable risk-benefit profile for glaucoma patients in need of cataract surgery. However, despite the promising results, use of MIGS in Italy has been extremely low. We aimed to investigate the reasons of the lower-than-expected use of Schlemm's canal-based MIGS devices in Italy, share our perspective on their potential place in therapy, and give practical suggestions to improve the management of glaucoma patients.

Laser Trabeculoplasty Perceptions and Practice Patterns of Canadian Ophthalmologists

Aim

To describe the current practice patterns and perceptions of Canadian ophthalmologists using laser trabeculoplasty (LTP).

Materials and methods

A cross-sectional survey of 124 members of the Canadian Ophthalmological Society (COS) who perform LTP was conducted. Descriptive statistics and Chi-square comparative analyses were performed on anonymous self-reported survey data.

Results

Of the 124 respondents, 34 (27.4%) completed a glaucoma fellowship. Use of selective laser trabeculoplasty (SLT) (94.4%) was preferred over argon laser trabeculoplasty (ALT) (5.6%). The most frequently cited reasons for SLT preference was less damage to trabecular meshwork (30.7%), availability (16.2%), and repeatability (16.2%). In all, 47.6% of the respondents performed LTP concurrently with medical treatment, 33.9% used it after medical treatment, and 17.7% used it as first-line treatment. Majority (87.1%) of the respondents believed that SLT is effective when repeated. In suitable patients, 41.9% of the respondents stated on average they repeat SLT once, 26.6% twice, and 19.4% greater than 2 times, respectively. Of those who repeat SLT on patients, 80.7% found repeat SLT treatments have good outcomes for patients. In all, 105 (84.7%) ophthalmologists responded they would benefit from an LTP practice guideline. Significantly more ophthalmologists without glaucoma fellowships perceived they would benefit from a practice guideline (p value <0.001).

Conclusion

This survey provides valuable practical information on how LTP is used in the treatment of glaucoma in Canada.

Clinical significance

The findings may serve as a baseline survey to trend future practices.

How to cite this article

Lee EY, Farrokhyar F, Sogbesan E. Laser Trabeculoplasty Perceptions and Practice Patterns of Canadian Ophthalmologists. J Curr Glaucoma Pract 2020;14(3):81–86.

Minimally Invasive Glaucoma Surgery: A Budget Impact Analysis and Evaluation of Patients' Experiences, Preferences, and Values

BACKGROUND

Glaucoma is a condition that causes progressive damage to the optic nerve, which can lead to visual impairment and irreversible blindness. There is a spectrum of current treatments for glaucoma that aim to reduce intraocular pressure (IOP), including pharmacotherapy (eye drops), laser therapy, and the more invasive option of filtration surgery. A new class of treatments called minimally invasive glaucoma surgery (MIGS) may reduce IOP and offer a better safety profile than more invasive procedures. We conducted a budget impact analysis of MIGS for adults with glaucoma from the perspective of the Ontario Ministry of Health and Long-Term Care. We also conducted interviews with people with glaucoma and family members of people with glaucoma to determine patient preferences and values surrounding glaucoma and its treatment options, including MIGS. We completed this work to complement a health technology assessment conducted in collaboration with the Canadian Agency for Drugs and Technologies in Health (CADTH).

METHODS

We analyzed the budget impact of publicly funding MIGS in adults with glaucoma in Ontario. We derived costs from the collaborative health technology assessment.¹ We assumed MIGS may be used in three subgroups: (1) MIGS in combination with cataract surgery as a replacement for cataract surgery alone in people with mild to moderate glaucoma; (2) MIGS alone as a replacement for other glaucoma treatments in people with mild to moderate glaucoma; and (3) MIGS (alone or in combination with cataract surgery) to replace filtration surgery (alone or in combination with cataract surgery) in people with advanced to severe glaucoma. We estimated the budget impact over 5 years for two possible uptake scenarios: a slow rate of uptake and a fast rate of uptake. To contextualize the lived experience of glaucoma and treatments for glaucoma, we also interviewed people with glaucoma and family members of people with glaucoma, some of whom had experience with surgical procedures such as MIGS and some of whom did not.

RESULTS

Assuming a slow uptake scenario, the annual budget impact of publicly funding MIGS in Ontario over the next 5 years ranges from $1 million in year 1 to $18 million in year 5. Assuming a fast uptake scenario, the annual budget impact of publicly funding MIGS in Ontario over the next 5 years ranges from $6 million in year 1 to $70 million in year 5. The budget impact varies depending on the proportion of people in each of the three subgroups described above. Introducing a new MIGS billing code may reduce the overall expenditures. Interview participants felt that less invasive surgical procedures, such as MIGS, could control glaucoma progression with minimal side effects and recovery time needed.

CONCLUSIONS

We estimate that publicly funding MIGS in Ontario would result in additional costs over the next 5 years; however, this may depend on the populations using MIGS and if uptake is restricted or controlled. For the people with glaucoma we spoke with, avoiding blindness was their paramount concern, and MIGS was perceived as an effective treatment option with minimal side effects and recovery time required.

Comparison of successful outcome predictors for MicroPulse® laser trabeculoplasty and selective laser trabeculoplasty at 6 months

Purpose: To identify and compare factors predictive of successful outcome for MicroPulse^® laser trabeculoplasty (MLT) and selective laser trabeculoplasty (SLT).

Methods: 50 MLT-treated eyes and 50 SLT-treated eyes of open-angle glaucoma patients were reviewed for baseline characteristics, pre- and postoperative IOP and medications, and adverse events including postoperative IOP elevation >5 mmHg (IOP spikes) through 6 months of follow-up. Success was defined as ≥20% IOP reduction or ≥1 medication reduction without additional IOP lowering procedures at 6 months follow-up.

Results: MLT and SLT had similar success rates (44% vs 40%, P=0.983). Older age predicted success for SLT (P=0.013) but not MLT (P=0.154). Both MLT and SLT led to greater IOP lowering in patients with baseline IOP >18 mmHg, but only for SLT did baseline IOP have a significant association with success (P=0.035 vs P=0.983). Number of laser shots was associated with success in MLT (P=0.031) but not in SLT (P=0.970). Glaucoma severity and pigmentation of the trabecular meshwork (PTM) were not associated with rate of success for either group. The rate of IOP spikes was significantly (P=0.022) higher in the SLT group (10%) compared to none in the MLT group. No other complications or visually significant adverse events occurred in either group.

Conclusion: Although MLT and SLT resulted in similar success rates, older age and higher baseline IOP predicted success for SLT while MLT was equally efficacious regardless of these factors. Glaucoma severity and PTM were not associated with success of either laser procedures. 10% of SLT patients experienced IOP spike post procedure, whereas none in the MLT group did. MLT may be a safer alternative to SLT that is effective in lowering IOP and need for medications for a wider variety of patients with open angle glaucoma.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/dSsXRth9lVA

Ab interno trabecular bypass surgery with iStent for open-angle glaucoma

BACKGROUND

Glaucoma is a leading cause of irreversible blindness worldwide. In early stages, glaucoma results in progressive loss of peripheral (side) vision; in later stages, it results in loss of central vision leading to blindness. Elevated intraocular pressure (IOP) is the only known modifiable risk factor for glaucoma. Minimally invasive glaucoma surgical (MIGS) techniques, such as ab interno trabecular bypass surgery with iStent (Glaukos Corporation, Laguna Hills, CA, USA), have been introduced as a new treatment modality for glaucoma. However, the effectiveness of MIGS on keeping people 'drop-free' (i.e. not having to use eye drops to control IOP) and other outcomes is uncertain.

OBJECTIVES

To assess the effectiveness and safety of ab interno trabecular bypass surgery with iStent (or iStent inject) for open-angle glaucoma in comparison to conventional medical, laser, or surgical treatment.

SEARCH METHODS

Cochrane Eyes and Vision's Information Specialist searched the following databases on 17 August 2018: the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register; 2018, Issue 7), MEDLINE Ovid, Embase Ovid, the ISRCTN registry, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We applied no date or language restrictions. We searched the reference lists of reports from included studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that had compared iStent or iStent inject to medical therapy, laser treatment, conventional glaucoma surgery (trabeculectomy), or other MIGS procedures. We included RCTs that had compared iStent or iStent inject in combination with phacoemulsification to phacoemulsification alone.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently screened search results, assessed risk of bias, and extracted data from reports of included RCTs using an electronic data collection form.

MAIN RESULTS

We included seven RCTs (765 eyes of 764 participants; range per study 33 to 239 participants) that evaluated iStent in people with open-angle glaucoma. We also identified 13 studies that are ongoing or awaiting publications of results. Most participants in the included studies were women (417/764 (55%) participants) and older age (age range: 49 to 89 years). We assessed most trials at unclear or high risk of bias: four trials did not clearly report the method of generating the random sequence or concealing allocation; five were unmasked, open-label studies, which we assessed at high risk of bias for performance and detection bias. All seven trials were funded by the Glaukos Corporation. We graded the certainty of evidence as very low.Four RCTs compared iStent in combination with phacoemulsification to phacoemulsification alone. The summary estimate which we derived from two of the four RCTs suggested that participants in the iStent in combination with phacoemulsification group were 1.38 times more likely to be drop-free between six and 18 months than those in the phacoemulsification alone group (risk ratio (RR) 1.38, 95% confidence interval (CI) 1.18 to 1.63, I² = 67%). Data from two RCTs also suggested that iStent in combination with phacoemulsification compared to phacoemulsification alone may have offered a small reduction in number of IOP-lowering drops (mean difference (MD) -0.42 drops, 95% CI -0.60 to -0.23). It is uncertain whether there was any difference in terms of mean reduction in IOP from baseline (no meta-analysis).Two RCTs compared treatment with iStent to medical therapy; one of the two trials used the iStent inject. We determined the two trials to be clinically and methodologically heterogeneous and did not conduct a meta-analysis; however, the investigators of both trials reported that over 90% of participants in the treatment groups were drop-free compared to no participants in the medical therapy groups at six to 18 months.One RCT compared treatment with one versus two versus three iStents. There was no difference in terms of participants who were drop-free at 36 months or less; however, at longer follow-up (i.e. at 42 months) participants in the one iStent treatment were less likely to be drop-free than those in the two iStent (RR 0.51, 95% CI 0.34 to 0.75) or three iStent (RR 0.49, 95% CI 0.34 to 0.73) treatment groups. The study did not report the mean change in number of IOP-lowering drops.The type and timing of complications reported varied by RCTs. Similar proportions of participants who underwent treatment with iStent in combination with phacoemulsification and who underwent phacoemulsification alone needed secondary glaucoma surgery. None of RCTs reported findings related to quality of life.

AUTHORS' CONCLUSIONS

There is very low-quality evidence that treatment with iStent may result in higher proportions of participants who are drop-free or achieving better IOP control, in the short, medium, or long-term. Results from the 13 studies with results not yet available may clarify the benefits of treatment of people with iStent. Additionally, future MIGS studies should consider measuring quality of life and outcomes that reflect people's ability to perform vision-dependent activities.

Efficacy of selective laser trabeculoplasty in primary angle closure disease

BACKGROUND

To study the role of selective laser trabeculoplasty (SLT) in intraocular pressure (IOP) reduction in post-laser iridotomy primary angle-closure disease patients with inadequately controlled IOP.

METHODS

In this prospective cross-sectional study, 34 patients with primary angle-closure disease with post-laser iridotomy open angles up to at least 180° were recruited. Following SLT, patients were examined at 1 day, 1 week, 1 and 3 months, 6 months and 1 year post SLT.

RESULTS

Data of 34 patients (34 eyes; 8 males and 26 females), with a mean age of 57.80 ± 6.44 years, were analysed. The reduction in IOP at each follow-up visit was significant (p < 0.001). The maximum reduction in IOP was noticed on post-laser day 1 and the least reduction was noticed 1 week post laser. Post-SLT range of IOP reduction varied from 9 to 46% at 1 year, which indicates the variability of a response to SLT. Mean IOP in both primary angle closure (PAC) and primary angle closure glaucoma (PACG) groups was comparable at all visits except at post-SLT week 1 when IOP in the PACG group was significantly higher than that in the PAC group (p = 0.035). None of the patients complained of pain and/or discomfort or had any clinically significant anterior segment inflammation on any of the follow-up visits. None of the patients underwent repeat SLT or surgery. The mean pre-SLT and post-SLT visual field index at 1-year follow-up was 95.47 ± 3.58 and 95.90 ± 4.13, respectively, which was not significant (p = 0.84).

CONCLUSIONS

High baseline IOP significantly correlated with reduction in IOP. Our results suggest that SLT is a safe, cost-effective modality for reducing IOP in primary angle-closure disease with patent laser iridotomy with a visible trabecular meshwork.

A Review of the Clinical Usefulness of Selective Laser Trabeculoplasty in Exfoliative Glaucoma

In the last decade, selective laser trabeculoplasty (SLT) has been commonly used in the management of several different types of glaucoma, as either primary or adjunct therapy. The technique has an excellent safety profile and is at least as effective as argon laser trabeculoplasty. Although the actual mechanism of action of SLT remains unclear, evidence has shown that it does not induce morphologically evident trabecular meshwork alterations. SLT's non-disruptive mode of action offers the advantage of repeatability. Exfoliation glaucoma (XFG) is a secondary open-angle glaucoma with unfavorable intraocular pressure (IOP) characteristics, which typically carries a poorer long-term prognosis than primary open-angle glaucoma. Consequently, patients with XFG often need multiple medications to achieve IOP levels that prevent disease progression. Because complicated pharmacotherapy regimens undermine the long-term tolerability and compliance of patients with XFG, options such as SLT may decrease the burden of multiple therapies and ultimately improve prognosis. In fact, SLT may be a particularly attractive option in XFG because the pigment-laden trabecular tissue of these patients enhances the absorption of laser energy and thus augments the biologic effects induced by this treatment. The current article reviews the postulated mechanisms of action of SLT, discusses practical aspects of SLT therapy, and examines selected peer-reviewed literature pertaining to the clinical usefulness of this modality in XFG patients.

Positive correlation between blood reflux in Schlemm's canal and the decrease of intraocular pressure after selective laser trabeculoplasty in primary open-angle glaucoma

The aim of the present study was to investigate the association between blood reflux in Schlemm's canal (SC) and the decrease of intraocular pressure (IOP) after selective laser trabeculoplasty (SLT) in primary open-angle glaucoma (POAG). To verify this, 35 eyes from 25 POAG patients were enrolled. All eyes underwent 360° whole-circle gonioscopy via a three-mirror lens, prior to undergoing 360° SLT. The four quadrants of the examined eye were individually compressed by the lens, and the presence of blood reflux in SC after removal of the pressure was recorded. Eyes with no blood reflux in any quadrant were assigned to the negative group, while the others were assigned to the positive group. Patients were evaluated at baseline, at 1 and 2 weeks, and at 1, 3 and 6 months after SLT. The results indicated that in the reflux-positive (21 eyes) and -negative (14 eyes) group, a significant IOP decrease was seen at 1 and 2 weeks, and at 1 and 3 months after SLT as compared with that pre-SLT IOP (P<0.01). In the negative group, the IOP at 6 months after SLT was not significantly different (P>0.05), while the positive group still exhibited a significant decrease in IOP compared with that at baseline (P<0.01). The positive group also presented with a greater decline in IOP at 1, 3 and 6 months compared with that in the negative group (P<0.05). A positive correlation between the number of quadrants with blood reflux in SC and the percentage decrease in IOP after SLT was identified in the positive group (P<0.05). In conclusion, blood reflux in SC was positively correlated with the decrease in IOP after SLT in POAG (Trialapproval number, K-2014-013).

Rare corneal complication following selective laser trabeculoplasty

Purpose

This case report describes two glaucoma patients who underwent selective laser trabeculoplasty (SLT) and developed a rare post-procedure corneal complication and subsequent permanent corneal distortions and reduced acuity.

Observations

Both patients experienced early post-procedure corneal edema, reduced visual acuity, and pain. Each patient was treated with topical steroids with resolution of the edema, but each patient had irregular corneal astigmatism which was not present pre-operatively and did not resolve.

Conclusions and importance

There are very few reported cases of post-SLT corneal edema and these typically resolve without long-term complications. The following two cases represent an uncommon adverse event of irregular corneal astigmatism despite resolution of the corneal edema. The exact mechanism of these corneal effects is not known. Practitioners should inform patients of this rare, but possible complication following SLT and consider extra precautions in patients susceptible to corneal edema.

Selective laser trabeculoplasty: past, present, and future

Over the past two decades, selective laser trabeculoplasty (SLT) has increasingly become an established laser treatment used to lower intraocular pressure in open-angle glaucoma and ocular hypertensive patients. In this review we trace the origins of SLT from previous argon laser trabeculoplasty and review the current role it has in clinical practice. We outline future directions of SLT research and introduce emerging technologies that are further developing this intervention in the treatment paradigm of glaucoma.

An Update on Implants for Minimally Invasive Glaucoma Surgery (MIGS)

For several years, the gold standard for surgical treatment of glaucoma has been trabeculectomy. Although very successful at reducing intraocular pressure (IOP), there are several potential complications of trabeculectomy, including sight-threatening ones. This has stimulated much research aimed at the development of new and effective procedures to lower IOP with an enhanced safety profile. Minimally invasive glaucoma surgery (MIGS) procedures prioritise patient safety but also demonstrate efficacy in reducing IOP. We performed an online search of peer-reviewed literature using PubMed, entering keywords relevant to this clinical discipline. In summary, there is a lack of long-term safety and efficacy data, a lack of comparative data and a lack of data on standalone (i.e. without simultaneous cataract surgery) procedures. Most implants are not yet FDA approved. Although not exhaustive, since it does not discuss MIGS procedures that are not implants, this article summarises the range of different MIGS implants that are available to the ophthalmic surgeon.

A Review of Selective Laser Trabeculoplasty: Recent Findings and Current Perspectives

Selective laser trabeculoplasty (SLT) has been widely used in the clinical management of glaucoma, both as primary and adjunctive treatment. As new evidence continues to arise, we review the current literature in terms of indications and efficacy, surgical technique, postoperative care, repeatability, and complications of this therapy. SLT has been shown to be effective in various glaucomas, including primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), steroid-induced glaucoma, pseudoexfoliation glaucoma (PXFG), and primary angle-closure glaucoma (PACG), as well as other glaucoma subtypes. Relatively high preoperative intraocular pressure (IOP) may predict surgical success, while other parameters that have been studied do not seem to affect the outcome. Different techniques for performing the procedure have recently been explored, revealing that minor modifications may lead to a more favorable or safer clinical outcome. The utilization of postoperative medications remains controversial based on the current evidence. A short-term IOP increase may complicate SLT and can also persist in certain cases such as in exfoliation glaucoma. The efficacy and safety of repeat SLT are shown in multiple studies, and the timing of repeat procedures may affect the success rate.

Ab interno trabecular bypass surgery with Trabectome for open angle glaucoma

BACKGROUND

Glaucoma is the leading cause of irreversible blindness. Minimally invasive surgical techniques, such as ab interno trabecular bypass surgery, have been introduced to prevent glaucoma progressing.

OBJECTIVES

The main objective was to assess the results at two years of ab interno trabecular bypass surgery with Trabectome for open angle glaucoma in comparison to conventional medical, laser, or surgical treatment in terms of efficacy and safety. A secondary objective was to examine the effects of Trabectome surgery in people who have concomitant phacoemulsification in comparison to those who do not have concomitant phacoemulsification.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 12 May 2016.

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) of ab interno trabecular bypass surgery with Trabectome.

DATA COLLECTION AND ANALYSIS

We planned to have two review authors independently extract data from reports of included studies using a data collection form.

MAIN RESULTS

One randomised controlled trial identified from ClinicalTrials.gov, NCT00901108, met the criteria for inclusion. This study has subsequently been terminated. The ClinicalTrials.gov record indicates that the investigators plan to complete 12 months of follow-up and analysis on 19 participants already recruited into the trial.

AUTHORS' CONCLUSIONS

There is currently no high-quality evidence for the outcomes of ab interno trabecular bypass surgery with Trabectome for open angle glaucoma. Properly designed RCTs are needed to assess the long-term efficacy and safety of this technique.

Glaucoma-inducing Procedure in an In Vivo Rat Model and Whole-mount Retina Preparation

Glaucoma is a disease of the central nervous system affecting retinal ganglion cells (RGCs). RGC axons making up the optic nerve carry visual input to the brain for visual perception. Damage to RGCs and their axons leads to vision loss and/or blindness. Although the specific cause of glaucoma is unknown, the primary risk factor for the disease is an elevated intraocular pressure. Glaucoma-inducing procedures in animal models are a valuable tool to researchers studying the mechanism of RGC death. Such information can lead to the development of effective neuroprotective treatments that could aid in the prevention of vision loss. The protocol in this paper describes a method of inducing glaucoma - like conditions in an in vivo rat model where 50 µl of 2 M hypertonic saline is injected into the episcleral venous plexus. Blanching of the vessels indicates successful injection. This procedure causes loss of RGCs to simulate glaucoma. One month following injection, animals are sacrificed and eyes are removed. Next, the cornea, lens, and vitreous are removed to make an eyecup. The retina is then peeled from the back of the eye and pinned onto sylgard dishes using cactus needles. At this point, neurons in the retina can be stained for analysis. Results from this lab show that approximately 25% of RGCs are lost within one month of the procedure when compared to internal controls. This procedure allows for quantitative analysis of retinal ganglion cell death in an in vivo rat glaucoma model.

Minimally invasive glaucoma surgery: current status and future prospects

Minimally invasive glaucoma surgery aims to provide a medication-sparing, conjunctival-sparing, ab interno approach to intraocular pressure reduction for patients with mild-to-moderate glaucoma that is safer than traditional incisional glaucoma surgery. The current approaches include: increasing trabecular outflow (Trabectome, iStent, Hydrus stent, gonioscopy-assisted transluminal trabeculotomy, excimer laser trabeculotomy); suprachoroidal shunts (Cypass micro-stent); reducing aqueous production (endocyclophotocoagulation); and subconjunctival filtration (XEN gel stent). The data on each surgical procedure for each of these approaches are reviewed in this article, patient selection pearls learned to date are discussed, and expectations for the future are examined.