Miniaturization in Glaucoma Monitoring and Treatment: A Review of New Technologies That Require a Minimal Surgical Approach

Automated classification of angle-closure mechanisms based on anterior segment optical coherence tomography images via deep learning

Purpose

To develop and validate deep learning algorithms that can identify and classify angle-closure (AC) mechanisms using anterior segment optical coherence tomography (AS-OCT) images.

Methods

This cross-sectional study included participants of the Handan Eye Study aged ≥35 years with AC detected via gonioscopy or on the AS-OCT images. These images were classified by human experts into the following to indicate the predominant AC mechanism (ground truth): pupillary block, plateau iris configuration, or thick peripheral iris roll. A deep learning architecture, known as comprehensive mechanism decision net (CMD-Net), was developed to simulate the identification of image-level AC mechanisms by human experts. Cross-validation was performed to optimize and evaluate the model. Human-machine comparisons were conducted using a held-out and separate test sets to establish generalizability.

Results

In total, 11,035 AS-OCT images of 1455 participants (2833 eyes) were included. Among these, 8828 and 2.207 images were included in the cross-validation and held-out test sets, respectively. A separate test was formed comprising 228 images of 35 consecutive patients with AC detected via gonioscopy at our eye center. In the classification of AC mechanisms, CMD-Net achieved a mean area under the receiver operating characteristic curve (AUC) of 0.980, 0.977, and 0.988 in the cross-validation, held-out, and separate test sets, respectively. The best-performing ophthalmologist achieved an AUC of 0.903 and 0.891 in the held-out and separate test sets, respectively. And CMD-Net outperformed glaucoma specialists, achieving an accuracy of 89.9 % and 93.0 % compared to 87.0 % and 86.8 % for the best-performing ophthalmologist in the held-out and separate test sets, respectively.

Conclusions

Our study suggests that CMD-Net has the potential to classify AC mechanisms using AS-OCT images, though further validation is needed.

Diagnosing glaucoma in primary eye care and the role of Artificial Intelligence applications for reducing the prevalence of undetected glaucoma in Australia

Glaucoma is the commonest cause of irreversible blindness worldwide, with over 70% of people affected remaining undiagnosed. Early detection is crucial for halting progressive visual impairment in glaucoma patients, as there is no cure available. This narrative review aims to: identify reasons for the significant under-diagnosis of glaucoma globally, particularly in Australia, elucidate the role of primary healthcare in glaucoma diagnosis using Australian healthcare as an example, and discuss how recent advances in artificial intelligence (AI) can be implemented to improve diagnostic outcomes. Glaucoma is a prevalent disease in ageing populations and can have improved visual outcomes through appropriate treatment, making it essential for general medical practice. In countries such as Australia, New Zealand, Canada, USA, and the UK, optometrists serve as the gatekeepers for primary eye care, and glaucoma detection often falls on their shoulders. However, there is significant variation in the capacity for glaucoma diagnosis among eye professionals. Automation with Artificial Intelligence (AI) analysis of optic nerve photos can help optometrists identify high-risk changes and mitigate the challenges of image interpretation rapidly and consistently. Despite its potential, there are significant barriers and challenges to address before AI can be deployed in primary healthcare settings, including external validation, high quality real-world implementation, protection of privacy and cybersecurity, and medico-legal implications. Overall, the incorporation of AI technology in primary healthcare has the potential to reduce the global prevalence of undiagnosed glaucoma cases by improving diagnostic accuracy and efficiency.

Ab-Externo MicroShunt versus Trabeculectomy in Primary Open-Angle Glaucoma: Two-Year Results from a Randomized, Multicenter Study

PURPOSE

To compare the effectiveness and safety of the MicroShunt (Santen Inc) versus trabeculectomy in patients with primary open-angle glaucoma (POAG).

DESIGN

Prospective, randomized, multicenter trial conducted in the United States and Europe.

PARTICIPANTS

Adult patients (aged 40-85 years) with mild to severe POAG inadequately controlled on maximum tolerated medical therapy and intraocular pressure (IOP) ≥ 15 mmHg and ≤ 40 mmHg.

METHODS

Patients were randomized 3:1 to stand-alone MicroShunt implantation (n = 395) or trabeculectomy (n = 132), both augmented with mitomycin C (MMC) 0.2 mg/ml for 2 minutes.

MAIN OUTCOME MEASURES

The primary effectiveness end point was surgical success, defined as ≥ 20% reduction in mean diurnal IOP from baseline with no increase in glaucoma medications. Secondary end points included changes in mean IOP and medication use from baseline and the need for postoperative interventions.

RESULTS

At 2 years, the rate of surgical success was lower in the MicroShunt group than in the trabeculectomy group (50.6% vs. 64.4%, P = 0.005). Mean diurnal IOP was reduced from 21.1 ± 4.9 mmHg at baseline to 13.9 ± 3.9 mmHg at 24 months in the MicroShunt group and from 21.1 ± 5.0 mmHg at baseline to 10.7 ± 3.7 mmHg at 24 months in the trabeculectomy group (P < 0.001 compared with baseline in both groups). Mean medication use decreased from 3.1 to 0.9 in the MicroShunt group and from 2.9 to 0.4 in the trabeculectomy group (P < 0.001 compared with baseline in both groups). Adverse events at 2 years were generally similar in the 2 groups, except that hypotony was more common in eyes undergoing trabeculectomy (51.1% vs. 30.9%, P < 0.001). Repositioning or explantation of the implant occurred in 6.8% of MicroShunt patients. The majority of these patients had device removal at the time of subsequent glaucoma surgery. Vision-threatening complications were uncommon in both groups.

CONCLUSION

At 2 years, both the MicroShunt and trabeculectomy provided significant reductions in IOP and medication use, with trabeculectomy continuing to have greater surgical success.

FINANCIAL DISCLOSURE(S)

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

The Role and Mechanism of Nicotinamide Riboside in Oxidative Damage and a Fibrosis Model of Trabecular Meshwork Cells

Purpose

To investigate the potential effects and mechanism of nicotinamide riboside (NR) on the oxidative stress and fibrosis model of human trabecular meshwork (HTM) cell line cells.

Methods

HTM cells were pretreated with NR, followed by the induction of oxidative injury and fibrosis by hydrogen peroxide (H2O2) and TGF-β2, respectively. Cell viability was tested using Hoechst staining and MTT assays, cell proliferation was assessed by EdU assay, and cell apoptosis was detected by flow cytometry and western blotting. DCFH-DA and DHE probes were used to measure the level of reactive oxygen species (ROS), and MitoTracker staining was used to measure the mitochondrial membrane potential (MMP). Fibrotic responses, including cell migration and deposition of extracellular matrix (ECM) proteins, were detected via Transwell assays, qRT-PCR, and immunoblotting.

Results

NR pretreatment improved the viability, proliferation, and MMP of H2O2-treated HTM cells. Compared to cells treated solely with H2O2, HTM cells treated with both NR and H2O2, exhibited a reduced rate of apoptosis and generation of ROS. Compared with H2O2 pretreatment, NR pretreatment upregulated expression of the JAK2/Stat3 pathway but inhibited mitogen-activated protein kinase (MAPK) pathway expression. Moreover, 10-ng/mL TGF-β2 promoted cell proliferation and migration, which were inhibited by NR pretreatment. Both qRT-PCR and immunoblotting showed that NR inhibited the expression of fibronectin in a TGF-β2-induced fibrosis model.

Conclusions

NR has a protective effect on oxidative stress and fibrosis in HTM cells, which may be related to the JAK2/Stat3 pathway and MAPK pathway.

Translational Relevance

Our research provides the ongoing data for potential therapy of NAD+ precursors in glaucoma.

Emerging glaucoma treatments: are we seeing an improvement in adherence?

Introduction

Non-adherence to glaucoma medication and poor follow-up is a global health concern.

Areas covered

Glaucoma remains one of the largest causes of irreversible blindness worldwide. Traditional treatment guidelines suggest topical eye drop medication as first line therapy followed by addition of supplementary medications before proceeding to more invasive glaucoma surgeries. Unfortunately, poor glaucoma self-management remains high, leading to disease progression and blindness. Recent advancements in the field of pharmacotherapies, surgeries, and behavioral approaches have taken aim at increasing support for glaucoma self-management. We review the current and emerging approaches towards glaucoma management, with the exception of bleb-based surgical approaches, to investigate if they have had an impact on adherence. Literature searches were conducted via MEDLINE (PubMed), Embase (Elsevier), Cochrane Library (Wiley), and Preprints from January 1st, 2018, to January 26th, 2023.

Expert opinion

The ability to offer patients a multitude of choices enables patients to tailor their glaucoma treatment to their values and lifestyle. Offering personalized patient education and coaching to support chronic glaucoma self-management would better enable patient engagement in whichever treatment path is chosen. Currently, literature regarding the impact of these new advancements on treatment engagement is lacking; this field is ripe for additional intervention and assessment.

[Micro-invasive glaucoma surgery]

Glaucoma is a severe, rapidly progressing disease that in the absence of proper treatment leads to blindness in 20% of patients. According to the World Glaucoma Association, this disease is the most socially significant in modern ophthalmology and requires searching for new and effective methods of treatment. This article presents the results of research and reviews on this issue, considers both conservative therapy and surgical methods of treatment, analyzes in detail modern methods of micro-invasive eye surgery actively used in clinical practice. The article also describes indications for a various types of interventions, as well as the effect achieved by them and the possible complications, and presents the conclusions about the possibility of using these procedures in wide clinical practice.

Vibration-Assisted Synthesis of Nanoporous Anodic Aluminum Oxide (AAO) Membranes

In recent years, many research achievements in the field of anodic aluminum oxide (AAO) membranes can be observed. Nevertheless, it is still an interesting research topic due to its high versatility and applications in various fields, such as template-assisted methods, filtration, sensors, etc. Nowadays, miniaturization is an integral part of different technologies; therefore, research on micro- and nanosized elements is relevant in areas such as LEDs and OLEDs, solar cells, etc. To achieve an efficient mixing process of fluid flow in straight nanopores, acoustofluidic physics has attracted great interest in recent decades. Unfortunately, the renewal of the electrolyte concentration at the bottom of a pore is limited. Thus, excitation is used to improve fluid mixing along nanosized diameters. The effect of excitation by high-frequency vibrations on pore geometry is also investigated. In this study, theoretical simulations were performed. Using theoretical calculations, the acoustic pressure, acoustic velocity, and velocity magnitude were obtained at frequencies of 2, 20, and 40 kHz. Moreover, nanoporous AAO membranes were synthesized, and the influence of high-frequency vibrations on the geometry of the pores was determined. Using a high-frequency excitation of 20 kHz, the thickness of the AAO membrane increased by 17.8%. In addition, the thickness increased by 31.1% at 40 kHz and 33.3% at the resonant frequency of 40 kHz. Using high-frequency vibrations during the anodization process, the electrolyte inside the pores is mixed, and as a result, a higher oxide growth rate and a deeper structure can be achieved. On the other hand, to obtain pores of the same depth, the reaction can be performed in a shorter time.

Conventional glaucoma implants and the new MIGS devices: a comprehensive review of current options and future directions

Glaucoma is a progressive optic neuropathy that is the second leading cause of preventable blindness worldwide, after cataract formation. A rise in the intraocular pressure (IOP) is considered to be a major risk factor for glaucoma and is associated with an abnormal increase of resistance to aqueous humour outflow from the anterior chamber. Glaucoma drainage devices have been developed to provide an alternative pathway through which aqueous humour can effectively exit the anterior chamber, thereby reducing IOP. These devices include the traditional aqueous shunts with tube-plate design, as well as more recent implants, such as the trabeculectomy-modifying EX-PRESS^® implant and the new minimally invasive glaucoma surgery (MIGS) devices. In this review, we will describe each implant in detail, focusing on their efficacy in reducing IOP and safety profile. Additionally, a critical and evidence-based comparison between these implants will be provided. Finally, we will propose potential developments that may help to improve the performance of current devices.

How to Measure Intraocular Pressure: An Updated Review of Various Tonometers

Intraocular pressure (IOP) is an important measurement that needs to be taken during ophthalmic examinations, especially in ocular hypertension subjects, glaucoma patients and in patients with risk factors for developing glaucoma. The gold standard technique in measuring IOP is still Goldmann applanation tonometry (GAT); however, this procedure requires local anesthetics, can be difficult in patients with scarce compliance, surgical patients and children, and is influenced by several corneal parameters. Numerous tonometers have been proposed in the past to address the problems related to GAT. The authors review the various devices currently in use for the measurement of intraocular pressure (IOP), highlighting the main advantages and limits of the various tools. The continuous monitoring of IOP, which is still under evaluation, will be an important step for a more complete and reliable management of patients affected by glaucoma.

Ab externo device for the treatment of glaucoma: direct flow from the anterior chamber to the ocular surface

A new microinvasive glaucoma surgery device, the Beacon Aqueous Microshunt (BAM), drains aqueous humor directly from the anterior chamber to the surface of the eye vs draining to enclosed spaces within the eye, where outflow resistance, including the episcleral venous pressure, might limit drainage effectiveness. The BAM has a 0.030 mm × 0.048 mm channel and provides a fixed resistance. For implantation, a 1.40 mm wide transcorneal incision into the anterior chamber was created with a posterolimbal outer placement under topical anesthesia. The surgery was easy to execute and had a flat learning curve. Preliminary and early experience have shown success with lowering intraocular pressure immediately postoperatively. In conclusion, the BAM offers a promising minimally invasive surgical procedure.

12-month clinical outcomes of combined phacoemulsification and ab interno trabeculectomy for open-angle glaucoma in the United Kingdom

BACKGROUND/OBJECTIVES

To describe intraocular pressure (IOP) and ocular hypotensive medication outcomes of combined phacoemulsification and ab interno trabeculectomy with the Kahook Dual Blade (KDB; New World Medical, Inc, Rancho Cucamonga, CA) in adults with cataract and open-angle glaucoma (OAG).

SUBJECTS/METHODS

Retrospective chart review of existing medical records. Data collected included intraocular pressure (IOP) and IOP-lowering medication use preoperatively and through up to 24 months postoperatively. Paired t-tests were utilized to compare preoperative to postoperative mean IOP and mean medications used.

RESULTS

Data from 32 eyes of 26 subjects were analyzed. Subjects were predominantly Caucasian (25/26) had mean (standard error) age of 79.3 (1.2) years, and eyes had moderate-advanced OAG (mean visual field mean deviation -8.3 [1.3] dB). Mean IOP was 19.8 (0.8) mmHg at baseline and 15.5 (0.6) mmHg (p<0.0001) after mean follow-up of 11.5 (1.0) months; IOP reductions of ≥20% were achieved in 20/32 eyes (62.5%). Mean medication use declined from 2.4 (0.2) medications per eye at baseline to 0.5 (0.2) at last follow-up (p<0.0001); 23/32 eyes (71.9%) were medication-free at last follow-up. No vision-threatening complications were observed.

CONCLUSIONS

Combined phacoemulsification and ab interno trabeculectomy with the KDB safely provided mean IOP reductions of 21.7% and mean IOP medication reductions of 83% after mean follow-up of 12 months in eyes with moderate to advanced OAG. This procedure provides medication-independence in most eyes with statistically and clinically significant IOP reductions.

Extraocular, periocular, and intraocular routes for sustained drug delivery for glaucoma

Although once daily anti-glaucoma drug therapy is a current clinical reality, most therapies require multiple dosing and there is an unmet need to develop convenient, safe, and effective sustained release drug delivery systems for long-term treatment to improve patient adherence and outcomes. One of the first sustained release drug delivery systems was approved for the reduction of intraocular pressure in glaucoma patients. It is a polymeric reservoir-type insert delivery system, Ocusert™, placed under the eyelid and on the ocular surface for zero-order drug release over one week. The insert, marketed in two strengths, released pilocarpine on the eye surface. While many clinicians appreciated this drug product, it was eventually discontinued. No similar sustained release non-invasive drug delivery system has made it to the market to date for treating glaucoma. Drug delivery systems under development include punctal plugs, ring-type systems, contact lenses, implants, microspheres, nanospheres, gels, and other depot systems placed in the extraocular, periocular, or intraocular regions including intracameral, supraciliary, and intravitreal spaces. This article discusses the advantages and disadvantages of the various routes of administration and delivery systems for sustained glaucoma therapy. It also provides the reader with some examples and discussion of drug delivery systems that could potentially be applied for glaucoma treatment. Interestingly, one intracamerally injected implant, Durysta™, was approved recently for sustained intraocular pressure reduction. However, long-term acceptance of such devices has yet to be established. The ultimate success of the delivery system will depend on efficacy relative to eye drop dosing, safety, reimbursement options, and patient acceptance. Cautious development efforts are warranted considering prior failed approaches for sustained glaucoma drug delivery. Neuroprotective approaches for glaucoma therapy including cell, gene, protein, and drug-combination therapies, mostly administered intravitreally, are also rapidly progressing towards assessment in humans.

[Treatment of secondary glaucoma following intravitreal anti-VEGF therapy with the XEN® gel stent and mitomycin C]

BACKGROUND

Recurrent treatment with intravitreal anti-VEGF (vascular endothelial growth factor) administration can in rare cases lead to secondary glaucoma that is difficult to adjust. The goal of this case series was to analyze the treatment results of the XEN® gel stent in combination with mitomycin C.

METHODS

The long-term follow-up over a period of 18 months was evaluated for 3 eyes in 3 patients that underwent treatment with a XEN® gel stent in combination with mitomycin C as a surgical procedure to reduce intraocular pressure.

RESULTS

The eyes had a baseline pressure of 21-31 mm Hg with 3-5 antiglaucoma medications following 15-25 intravitreal injections. In all 3 eyes a pressure drop of almost 50% to 9-14 mm Hg could be achieved after 18 months with complete discontinuation of all local and systemic medications to reduce intraocular pressure in 2 of the 3 eyes. In 1 eye a choroidal detachment occurred for 2 weeks postoperatively. In another eye a surgical revision of conjunctival penetration was carried out. In two eyes needling was necessary due to scarring. In 2 out of 3 eyes, further intravitreal treatment (9 and 13 respectively) was necessary due to the macular disease but no further increase in intraocular pressure occurred.

CONCLUSION

The XEN® gel stent in combination with mitomycin C is a therapeutic option for difficult to adjust secondary glaucoma following intravitreal anti-VEGF therapy. A continuation of intravitreal anti-VEGF therapy did not lead to a recurrent increase of intraocular pressure.

Medical anti-glaucoma therapy: Beyond the drop

Barriers to effective medical therapy are numerous and include difficulties with effective and sustained control of intraocular pressure (IOP) and adherence to prescribed anti-glaucoma drop regimens. In an effort to circumvent these challenges, a number of new anti-glaucoma therapies with sustained effects have emerged. Methods for sustained delivery of prostaglandin analogs are being intensely investigated and many are in human clinical trials. Intracameral devices include the following: Allergan's Durysta^™ Bimatoprost SR, Envisia Therapeutics' ENV515 travoprost implant, Glaukos' iDose^™ , Ocular Therapeutix's OTX-TIC travoprost implant, and Santen's polycaprolactone implant with PGE2-derivative DE-117. Other prostaglandin-based technologies include Allergan's bimatoprost ring (placed in the conjunctival fornix), Ocular Therapeutics' OTX-TP intracanalicular travoprost implant, subconjunctival latanoprost in a liposomal formulation, and the PGE2 derivative PGN 9856-isopropyl ester that is applied to the periorbital skin. Exciting breakthroughs in gene therapy include using viral vectors to correct defective genes such as MYOC or to modulate gonioimplant fibrosis, CRISPR technology to edit MYOC or to alter aquaporin to reduce aqueous humor production, and siRNA technology to silence specific genes. Stem cell technology can repopulate depleted tissues or, in the case of Neurotech's Renexus® NT-501 intravitreal implant, serve as a living drug delivery device that continuously secretes neurotrophic factors. Other unique approaches involve nanotechnology, nasal sprays that deliver drug directly to the optic nerve and noninvasive alternating current stimulation of surviving cells in the optic nerve. Over time these modalities are likely to challenge the preeminent role that drops currently play in the medical treatment of glaucoma in animals.

Minimally Invasive Surgery, Implantable Sensors, and Personalized Therapies

Glaucoma management has changed dramatically over the last decades, through clinical advances and technological revolutions. This review discusses the latest innovations and challenges faced in the field around three major axes: minimally-invasive glaucoma surgery (MIGS), implantable sensors and injectable therapeutics. Indeed, the vast number of recently developed MIGS techniques has not only provided clinicians with a wide range of therapeutic options, but they have also enabled them to adjust their therapies more finely which may have contributed a more patient-centric decision-making process. Yet, despite considerable advances in the field, the wide heterogeneity in clinical trial designs blurs the surgical outcomes, specificities and indications. Thus, more high-quality data are required to make the choice of a specific MIGS procedure more than an educated guess. Beyond the scope of MIGS, the potential of IOP telemetry for self-assessment of IOP-control through implantable sensors is developing into a real option for clinicians and an empowering opportunity for patients. Indeed, providing patients with direct feedback enables them to take control and have a clearer representation of their care, in turn leading to a better control of the disease. However, there are potential issues with self-monitoring of IOP, such as increased anxiety levels induced by measured IOP fluctuations and peaks, leading to patients self-treating during IOP spikes and additional office visits. Furthermore, the advent of implantable therapeutics may soon provide yet another step towards personalized glaucoma treatment, by offering not only an efficient alternative to current treatments, but also a therapeutic option that may better adapt to patients' lifestyle. After several decades of relative stagnation through the last century, glaucoma has now entered what many view as a golden age for the specialty. Like every revolution, this one brings its fair share of uncertainty, clinical questioning and uneasy periods of adaptation to ever-changing expectations. Yet, while it is impossible to guess what the landscape of glaucoma surgery will be like in ten or fifteen years, data suggest a bright outlook both for patients and clinicians.

Influence of electromagnetic radiation emitted by daily-use electronic devices on the Eyemate® system in-vitro: a feasibility study

BACKGROUND

Eyemate® is a system for the continual monitoring of intraocular pressure (IOP), composed of an intraocular sensor, and a hand-held reader device. As the eyemate®-IO sensor communicates with the hand-held reader telemetrically, some patients might fear that the electronic devices that they use on a daily basis might somehow interfere with this communication, leading to unreliable measurements of IOP. In this study, we investigated the effect of electromagnetic radiation produced by a number of everyday electronic devices on the measurements made by an eyemate®-IO sensor in-vitro, in an artificial and controlled environment.

METHODS

The eyemate®-IO sensor was suspended in a sterile 0.9% sodium chloride solution and placed in a water bath at 37 °C. The antenna, connected to a laptop for recording the data, was positioned at a fixed distance of 1 cm from the sensor. Approximately 2 hrs of "quasi-continuous" measurements were recorded for the baseline and for a cordless phone, a smart-phone and a laptop. Repeated measures ANOVA was used to compare any possible differences between the baseline and the tested devices.

RESULTS

For baseline measurements, the sensor maintained a steady-state, resulting in a flat profile at a mean pressure reading of 0.795 ± 0.45 hPa, with no apparent drift. No statistically significant difference (p = 0.332) was found between the fluctuations in the baseline and the tested devices (phone: 0.76 ± 0.41 hPa; cordless: 0.787 ± 0.26 hPa; laptop: 0.775 ± 0.39 hPa).

CONCLUSION

In our in-vitro environment, we found no evidence of signal drifts or fluctuations associated with the tested devices, thus showing a lack of electromagnetic interference with data transmission in the tested frequency ranges.

The potential application of artificial intelligence for diagnosis and management of glaucoma in adults

BACKGROUND

Glaucoma is the most frequent cause of irreversible blindness worldwide. There is no cure, but early detection and treatment can slow the progression and prevent loss of vision. It has been suggested that artificial intelligence (AI) has potential application for detection and management of glaucoma.

SOURCES OF DATA

This literature review is based on articles published in peer-reviewed journals.

AREAS OF AGREEMENT

There have been significant advances in both AI and imaging techniques that are able to identify the early signs of glaucomatous damage. Machine and deep learning algorithms show capabilities equivalent to human experts, if not superior.

AREAS OF CONTROVERSY

Concerns that the increased reliance on AI may lead to deskilling of clinicians.

GROWING POINTS

AI has potential to be used in virtual review clinics, telemedicine and as a training tool for junior doctors. Unsupervised AI techniques offer the potential of uncovering currently unrecognized patterns of disease. If this promise is fulfilled, AI may then be of use in challenging cases or where a second opinion is desirable.

AREAS TIMELY FOR DEVELOPING RESEARCH

There is a need to determine the external validity of deep learning algorithms and to better understand how the 'black box' paradigm reaches results.

Twelve-Month Outcomes of Stand-Alone Excisional Goniotomy in Mild to Severe Glaucoma

PURPOSE

To describe 12-month intraocular pressure (IOP) and medication use outcomes following excisional goniotomy (EG) as a stand-alone procedure in eyes with medically uncontrolled glaucoma.

METHODS

This was a retrospective analysis of data from surgeons at 8 centers (6 US, 2 Mexico). Eyes with glaucoma undergoing standalone EG with a specialized instrument (Kahook Dual Blade, New World Medical, Rancho Cucamonga, CA) for IOP reduction and followed for 12 months postoperatively were included. Data were collected preoperatively, intraoperatively, and 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. The primary outcome was reduction from baseline in IOP, and key secondary outcomes included IOP-lowering medication reduction as well as adverse events.

RESULTS

A total of 42 eyes were analyzed, of which 36 (85.7%) had mild to severe primary open-angle glaucoma (POAG). Mean (standard error) IOP at baseline was 21.6 (0.8) mmHg, and mean number of medications used at baseline was 2.6 (0.2). At 3, 6, and 12 months postoperatively, mean IOP reductions from baseline were 4.6 mmHg (22.3%), 5.6 mmHg (27.7%), and 3.9 mmHg (19.3%) (p≤0.001 at each time point). At the same time points, mean medications reductions of 0.7 (25.8%), 0.9 (32.6%), and 0.3 (12.5%) medications were seen (p<0.05 at months 3 and 6, not significant at month 12). Six eyes (14.3%) underwent additional glaucoma surgery during the 12-month follow-up period.

DISCUSSION

Standalone EG with KDB can reduce IOP, and in many cases reduce medication use, through up to 12 months in eyes with mild to severe glaucoma. Statistically significant and clinically relevant reductions in IOP were seen at every time point. While the goal of surgery was not to reduce medication burden, mean medication use was significantly reduced at all but the last time point. In the majority of eyes, the need for a bleb-based glaucoma procedure was delayed or prevented for at least 12 months.

Minimally Invasive Glaucoma Surgery: What Do We Know? Where Should We Go?

With the arrival of a plethora of new and revolving minimally invasive glaucoma surgery techniques, glaucoma specialists currently are fortunate to have various surgical options that aim to recovery of the function of the aqueous outflow system in different ways. Meanwhile, the aqueous outflow system has become the hot point of researching. In ARVO 2019, a special interest group session was held on new perspectives on minimally invasive glaucoma surgery. Ten surgeons, clinical professors, and experimental scientists were invited to report their latest studies and discussed on five hot topics in this special interest group. This review summarizes the special interest group session and posts the issues of greatest concern, providing insight to the aqueous outflow system and areas that require further study.