Selective Laser Trabeculoplasty: A Clinical Review

Advancements in Ocular Therapy: A Review of Emerging Drug Delivery Approaches and Pharmaceutical Technologies

Eye disorders affect a substantial portion of the global population, yet the availability of efficacious ophthalmic drug products remains limited. This can be partly ascribed to a number of factors: (1) inadequate understanding of physiological barriers, treatment strategies, drug and polymer properties, and delivery systems; (2) challenges in effectively delivering drugs to the anterior and posterior segments of the eye due to anatomical and physiological constraints; and (3) manufacturing and regulatory hurdles in ocular drug product development. The present review discusses innovative ocular delivery and treatments, encompassing implants, liposomes, nanoparticles, nanomicelles, microparticles, iontophoresis, in situ gels, contact lenses, microneedles, hydrogels, bispecific antibodies, and gene delivery strategies. Furthermore, this review also introduces advanced manufacturing technologies such as 3D printing and hot-melt extrusion (HME), aimed at improving bioavailability, reducing therapeutic dosages and side effects, facilitating the design of personalized ophthalmic dosage forms, as well as enhancing patient compliance. This comprehensive review lastly offers insights into digital healthcare, market trends, and industry and regulatory perspectives pertaining to ocular product development.

Effectiveness of Angle-Based Minimally Invasive Glaucoma Surgery after Laser Trabeculoplasty: An Analysis of the IRIS® Registry (Intelligent Research in Sight)

OBJECTIVE

Angle-based minimally invasive glaucoma surgery (ab-MIGS) has grown substantially, although long-term efficacy is poorly understood. We analyze ab-MIGS effectiveness with and without preceding laser trabeculoplasty (LTP).

DESIGN

Retrospective cohort study.

SUBJECTS

Eyes undergoing ab-MIGS (Canaloplasty, Goniotomy, Trabectome, and iStent) with and without prior laser trabeculoplasty (< 2 years preceding MIGS) were identified in the IRIS® Registry (Intelligent Research in Sight) 2013 to 2018.

METHODS

Propensity score matching (PSM) was undertaken to define the following 4 cohorts: (1) standalone ab-MIGS, no prior LTP vs. (2) standalone ab-MIGS, with prior LTP; and (3) ab-MIGS + phacoemulsification, no prior LTP vs. (4) ab-MIGS + phacoemulsification, with prior LTP.

MAIN OUTCOME MEASURES

Failure was defined as subsequent glaucoma reoperation after ab-MIGS (either MIGS or traditional glaucoma surgery). Time-to-event outcome and incidence rates were calculated using survival analysis, and adjusted hazard ratios (aHRs) were generated using multivariate Cox proportional hazards models. Medication data were not available for analysis.

RESULTS

A total of 164 965 unique MIGS procedures were performed, from 2013 to 2018. After PSM, we identified 954 eyes undergoing standalone ab-MIGS and 7522 undergoing ab-MIGS + phacoemulsification. For eyes undergoing standalone ab-MIGS, those with prior LTP (n = 477) were more likely to undergo reoperation vs. those without LTP (n = 477) at 6 and 12 months. In multivariable models, those with prior LTP were more likely to undergo reoperation over the 36-month period vs. those without prior LTP (aHR, 1.53; CI, 1.15-2.04; P = 0.004). For eyes undergoing ab-MIGS + phacoemulsification, those with prior LTP (n = 3761) were more likely to undergo reoperation vs. those without LTP (n = 3761) at 12, 24, and 36 months. In multivariable models, those with prior LTP were more likely to undergo reoperation over the 36-month period vs. those without prior LTP (aHR, 1.53 CI, 1.15-2.04; P = 0.004).

CONCLUSIONS

Prior LTP may be associated with a higher chance of subsequent glaucoma surgery following ab-MIGS, either with or without concurrent phacoemulsification. These findings have important implications for understanding who may benefit most from ab-MIGS, and for guiding patient and surgeon treatment expectations.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Effect of Selective Laser Trabeculoplasty on the Fellow Eye

Aim

Determine if selective laser trabeculoplasty (SLT) affects the fellow eye's intraocular pressure (IOP).

Materials and methods

A retrospective review of 76 pairs of eyes from 76 adult glaucoma patients who underwent SLT in one eye with at least 2 months between treatments were evaluated for IOP and medication reduction in the untreated fellow eye. Success was defined as ≥20% IOP reduction or ≥1 medication reduction without any additional IOP lowering procedures or medication. The primary outcome measures were success, IOP, and medication reduction in the untreated fellow eye at 6 months.

Results

At 6 months after SLT treatment, 48.7% (38/76) treated eyes and 36.8% (28/76) untreated fellow eyes met success criteria. IOP reduction in the treated eye was 2.6 ± 5.8 (14.1%; p < 0.002) and 0.8 ± 4.3 (5.1%, p = 0.122) in the fellow eye. The fellow eye was significantly more likely to meet success criteria if the treated eye was successful [odds ratio (OR): 6.00, 95% confidence interval (CI) (2.11-17.06), p < 0.002].

Conclusion

After a unilateral treatment with SLT, over one-third of the fellow eyes experienced either ≥20% IOP reduction or medication reduction. Additionally, fellow eyes were six times as likely to meet success criteria if this was observed in the treated eye. These findings may support the proposed biochemical mechanism for the therapeutic action of SLT.

Clinical significance

The implication for clinicians is that SLT treatment in one eye may allow the fellow eye to benefit and provide a prediction on the fellow eye's response without subjecting both eyes to the rare but present complications of SLT.

How to cite this article

Hirabayashi M, Mellencamp E, Duong S, et al. Effect of Selective Laser Trabeculoplasty on the Fellow Eye. J Curr Glaucoma Pract 2023;17(4):175-177.

Choroidal detachment and hypotony following selective laser trabeculoplasty: a case report

BACKGROUND

Selective laser trabeculoplasty (SLT) is relatively safe and effective in lowering intraocular pressure (IOP). However, although rare, complications can occur after SLT. This report describes a patient with choroidal detachment due to hypotony following SLT without anterior chamber (AC) inflammation.

CASE PRESENTATION

A 67-year-old man was referred for elevated IOP in his left eye with advanced glaucomatous visual field loss. He had previously been diagnosed with idiopathic uveitic glaucoma in the left eye, for which he underwent laser iridotomy, trabeculectomy, and cataract surgery. At the first visit, the IOP of his left eye measured by Goldmann tonometry was 28 mmHg despite maximally tolerated medical treatment. SLT was performed in his left eye, resulting in an IOP of 7 mmHg 7 days later. At 3 weeks post-procedure, the patient experienced ocular pain and decreased visual acuity in his left eye. Slit-lamp examination revealed deep anterior chamber depth and no inflammation reaction, but the IOP in his left eye was 4 mmHg, and both fundus and B-scan ultrasonography showed serous choroidal detachment. All anti-glaucoma agents were stopped, and the patient was started on treatment with oral prednisolone and cyclopentolate eye drops. Three weeks later, choroidal detachment had resolved and the IOP in his left eye had stabilized at 8 mmHg. Follow-up 3 months later showed that the IOP in his left eye remained stable.

CONCLUSIONS

Choroidal detachment-related hypotony is a rare complication of SLT. This possible complication following SLT should be informed to the patients and considered when performing the procedure.

Glaucoma medical treatment as a predictor of XEN45 subconjunctival gel implant hypotensive efficacy

PURPOSE

The aim of this study was to determine the preoperative characteristics influencing hypotensive efficacy of the XEN45 gel stent in patients with open-angle glaucoma at one-year follow-up.

MATERIALS AND METHODS

This was a retrospective multicentre study. All patients who underwent XEN45 gel stent implantation between January 2017 and January 2021 were included. The main study outcome was the assessment of one-year postoperative intraocular pressure (IOP) and glaucoma medication differences according to the number and type of preoperative topical treatments or glaucoma surgery, glaucoma stage and time since diagnosis. Follow-up period was 1-year post-surgery in all cases. IOP reduction and surgery success (not requiring reoperation or pressure failures [IOP > 18 mmHg and < 20% reduction in IOP]), safety and cost savings in topical glaucoma therapy after surgery were secondarily assessed. Linear regression analysis to determine the preoperative parameters influence on 1-year postoperative results was performed.

RESULTS

XEN45 gel stent was implanted in 85 patients. One-year postoperative mean IOP dropped from 20.6 ± 4.1 to 13.7 ± 2.8 mmHg (p < 0.0001). Likewise, mean number of topical treatments decreased from 2.05 ± 0.9 to 0.36 ± 0.65 (p < 0.001). Both were mainly influenced by the number of preoperative glaucoma treatments, such that for each one-glaucoma medication increase, postoperative intraocular pressure increased by 1.18 mmHg (95% CI 0.56-1.79, p < 0.0001) and number of glaucoma medications increased by 0.3 (95% CI 0.16-0.43, p < 0.001). Overall success rates (with and without supplemental glaucoma medication use) were 97.6% (95% CI 94.5-100%), 87.1% (95% CI 80.2-87.1%) and 61.2% (95% CI 51.6-72.5%) at 3, 6 months and 1 year after surgery. No sight-threatening adverse events were reported. Mean annual cost savings on medical treatment since surgery reached EUR 251.19 ± 169. 93 euros.

CONCLUSIONS

One year after surgery, XEN45 gel implant significantly reduced IOP and number of topical medications with an adequate safety profile being both mainly influenced by the number of preoperative glaucoma treatments.

A Review of Selective Laser Trabeculoplasty: "The Hype Is Real"

Presently, there is no efficacious treatment for glaucomatous optic neuropathy; the current treatment is focused on lowering intraocular pressure (IOP). Studies have demonstrated the safety and efficacy of selective laser trabeculoplasty (SLT) in reducing the IOP in eyes with open-angle (OAG) glaucoma or ocular hypertension (OH). Moreover, the European Glaucoma Society has instated SLT as the first-line or adjunctive treatment in OAG or OH, reiterating its clinical significance. In this review, we outline the old and the new roles of SLT, with an emphasis on clinical practice, and look further into its renewed appeal and future developments.

Characteristics of glaucoma patients with intraocular pressure elevation early after trabectome surgery

PURPOSE

To analyze the rate and time of occurrence of intraocular pressure (IOP) elevation early after trabectome surgery (TOM) and the characteristics of glaucoma patients recovering from IOP elevation.

METHOD

Four hundred sixty eyes of 460 glaucoma (191 primary and 269 secondary open-angle glaucoma) patients who underwent TOM were evaluated. IOP elevation early after TOM was diagnosed when IOP increased by more than 5 mmHg over baseline within 1 week to 3 months. If the IOP decreased with the administration of anti-glaucoma eye drops alone, patients were classified as recovered. If the IOP did not decrease despite additional anti-glaucoma eye drop use, patients were classified as non-recovered. The rate and time of occurrence of IOP elevation early after TOM were investigated. Demographic and ocular variables related to recovery and non-recovery were identified by multivariate logistic regression analysis.

RESULTS

Of the 460 patients, IOP elevation early after TOM occurred in 102 (22.2%). IOP elevation occurred most frequently at postoperative week 1. Of the 102 patients with IOP elevation, 55 (53.9%) recovered and 47 (46.1%) did not. A large hyphema size the day after surgery was associated with increased likelihood of recovery from IOP elevation (odds ratio [OR], 6.6). A history of past selective laser trabeculoplasty (SLT; OR, 0.10) and high baseline IOP (OR, 0.86) were associated with reduced likelihood of recovery from IOP elevation.

CONCLUSION

IOP elevation early after TOM occurred most frequently at postoperative week 1. Patients with a large hyphema size, no history of SLT, and a lower baseline IOP recovered from IOP elevation early after TOM. A large hyphema the day after surgery suggested an increased likelihood of recovery from IOP elevation.

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.

[Preliminary selective laser trabeculoplasty (SLT) intraocular pressure results in glaucoma patients in Burkina Faso]

INTRODUCTION

Glaucoma is the leading cause of irreversible blindness in the world. The purpose of our study was to evaluate the tonometric results of SLT treatment in patients with glaucoma.

MATERIALS AND METHODS

This was a prospective study of patients with glaucoma who were seen from October 1, 2017 to July 31, 2018. All patients underwent SLT of the inferior 180°. Intraocular pressure (IOP) was measured before and then at 1, 15, 30, 60, 90 and 120days after treatment.

RESULTS

We studied 35 eyes of 31 patients. The mean age was 59.3 (±8.4years), range 43-77years. The mean IOP prior to SLT was 20.1mmHg (±7mmHg). One day after the laser, this decreased to 17.6mmHg (±8.4), for a percentage of drop of 12.4%. At 30days, it was 15.3mmHg (±5.4mmHg), i.e. a 23.9% decrease. After 60 and 90days, there was a drop of 13.9% and 15.4%, respectively. At 120days, 43.3% of treated eyes had a decrease of at least 20%. The main complication was increased IOP in 14.2% of cases.

CONCLUSION

SLT reduces IOP and the number of glaucoma medications in patients. It appears to be a viable alternative in our countries. These results should be confirmed with a larger cohort and longer follow-up.

Long-term clinical results of trabectome surgery in patients with open-angle glaucoma

PURPOSE

To evaluate the 72-month clinical results of trabectome surgery (TOM) in patients with primary open-angle glaucoma (POAG), secondary OAG and childhood glaucoma.

METHOD

A total of 305 eyes from 249 glaucoma patients were analyzed in the current retrospective single-center study. Kaplan-Meier analysis was performed using three criteria: criterion A (postoperative intraocular pressure [IOP] ≤ 21 mmHg and ≥ 20% reduction from baseline IOP); criterion B (postoperative IOP ≤ 18 mmHg and ≥ 20% reduction from baseline IOP); and criterion C (postoperative IOP ≤ 16 mmHg and ≥ 20% reduction from baseline IOP). The changes in IOP, medication score, success probability, results of the multivariate analysis for success and failure risk factors, and complications were analyzed.

RESULTS

The baseline IOP in all glaucoma patients decreased from 29.2 ± 9.8 mmHg with a 5.3 ± 1.7 medication score to 16.4 ± 5.8 mmHg (- 43.8%) with a 4.2 ± 1.5 medication score at 72 months (p < 0.01). The success probabilities in all cases for 72 months based on criterion A, B, and C were 44%, 35%, and 17%, respectively. For criterion A, no significant differences were found in the success probability according to the glaucoma subtype for 72 months. The combined surgical procedure significantly decreased the failure risk (hazard ratio [HR]: 0.59). On the other hand, the presence of POAG (HR: 1.6) and a history of past selective laser trabeculoplasty (HR: 2.2) significantly increased failure risk. One patient (0.3%) demonstrated endophthalmitis after TOM but recovered through appropriate treatment.

CONCLUSION

At the 72-month time point, approximately half of the glaucoma patients maintained an IOP ≤ 21 mmHg with ≥ 20% IOP reduction. TOM is a safe surgery but may not yield sufficient IOP reduction in patients who have received SLT or have POAG.

Comparison of the effects of 180° and 360° applications of selective laser trabeculoplasty on intraocular pressure and cornea

PURPOSE

To compare the effects of 180° and 360° selective laser trabeculoplasty (SLT) on intraocular pressure (IOP) and cornea in patients with bilateral primary open-angle glaucoma.

METHODS

Fifty-two eyes of 26 patients were included. On the same day, 180° SLT (Group 1) was applied to one eye of patients and 360° SLT (Group 2) to the other eye. IOP values were compared at pre-SLT and post-SLT 1 day, 1 week, 1, 3, and 6 months. Changes in central corneal thickness (CCT) and endothelial cell count (ECC) were examined.

RESULTS

In groups, significant decreases were observed in IOP at 1 week (p < 0.05), 1, 3, and 6 months (p < 0.001). No significant difference was determined between group 1 and 2 in IOP-lowering effectiveness or success rates (p > 0.05). There was no significant difference in CCT at inter- or intragroup comparisons (p > 0.05). In group 1, no significant difference was determined in pre- and post-SLT ECC (p > 0.05). In group 2, significant decrease in ECC was observed at 1 week (p < 0.05). However, ECC returned to its initial levels at 1 month.

CONCLUSIONS

To the best of our knowledge, this is the first study in literature to compare different quadrant SLT applications performed on both eyes, on the same day, in the same patient group and to compare the effects of those applications on IOP and cornea. In reducing IOP, 180° and 360° SLT are similarly effective. These effects begin on the 1st week and persist for 6 months. Temporary corneal changes may be observed following 360° SLT.

Paradigm Shifts in Ophthalmic Diagnostics

PURPOSE

Future advances in ophthalmology will see a paradigm shift in diagnostics from a focus on dysfunction and disease to better measures of psychophysical function and health. Practical methods to define genotypes will be increasingly important and non-invasive nanotechnologies are needed to detect molecular changes that predate histopathology.

METHODS

This is not a review nor meant to be comprehensive. Specific topics have been selected to illustrate the principles of important paradigm shifts that will influence the future of ophthalmic diagnostics. It is our impression that future evaluation of vision will go beyond visual acuity to assess ocular health in terms of psychophysical function. The definition of disease will incorporate genotype into what has historically been a phenotype-centric discipline. Non-invasive nanotechnologies will enable a paradigm shift from disease detection on a cellular level to a sub-cellular molecular level.

RESULTS

Vision can be evaluated beyond visual acuity by measuring contrast sensitivity, color vision, and macular function, as these provide better insights into the impact of aging and disease. Distortions can be quantified and the psychophysical basis of vision can be better evaluated than in the past by designing tests that assess particular macular cell function(s). Advances in our understanding of the genetic basis of eye diseases will enable better characterization of ocular health and disease. Non-invasive nanotechnologies can assess molecular changes in the lens, vitreous, and macula that predate visible pathology. Oxygen metabolism and circulatory physiology are measurable indices of ocular health that can detect variations of physiology and early disease.

CONCLUSIONS

This overview of paradigm shifts in ophthalmology suggests that the future will see significant improvements in ophthalmic diagnostics. The selected topics illustrate the principles of these paradigm shifts and should serve as a guide to further research and development. Indeed, successful implementation of these paradigm shifts in ophthalmology may provide useful guidance for similar developments in all of healthcare.