Clinical options for the reduction of elevated intraocular pressure

Identification of the novel role of sterol regulatory element binding proteins (SREBPs) in mechanotransduction and intraocular pressure regulation

Trabecular meshwork (TM) cells are contractile and mechanosensitive, and they aid in maintaining intraocular pressure (IOP) homeostasis. Lipids are attributed to modulating TM contractility, with poor mechanistic understanding. In this study using human TM cells, we identify the mechanosensing role of the transcription factors sterol regulatory element binding proteins (SREBPs) involved in lipogenesis. By constitutively activating SREBPs and pharmacologically inactivating SREBPs, we have mechanistically deciphered the attributes of SREBPs in regulating the contractile properties of TM. The pharmacological inhibition of SREBPs by fatostatin and molecular inactivation of SREBPs ex vivo and in vivo, respectively, results in significant IOP lowering. As a proof of concept, fatostatin significantly decreased the SREBPs responsive genes and enzymes involved in lipogenic pathways as well as the levels of the phospholipid, cholesterol, and triglyceride. Further, we show that fatostatin mitigated actin polymerization machinery and stabilization, and decreased ECM synthesis and secretion. We thus postulate that lowering lipogenesis in the TM outflow pathway can hold the key to lowering IOP by modifying the TM biomechanics.

Preventing Blindness with Early Cataract Surgery and Micro-Invasive Glaucoma Surgery in Patients Over 50: Guidance for Patients, Physicians and World Governments in Dealing with Glaucoma

Purpose

To offer clinical guidance and address safety and efficacy concerns regarding the growing use of micro-invasive glaucoma surgery (MIGS) as an initial treatment for glaucoma in adult patients.

Design

Narrative literature review.

Methods

A review was conducted to assess outcomes and complications of MIGS in the treatment of glaucoma, both alone and in combination with lens replacement. These outcomes were compared with those of standard glaucoma surgery and/or glaucoma management with medication.

Results

MIGS are effective at lowering intraocular pressure (IOP) over long periods of follow-up. These techniques share a similarly high safety profile between one another. MIGS were found to have lower complication rates and to be more effective in reducing the total amount of medication needed to maintain control of intraocular pressure than standard surgery approaches.

Conclusion

MIGS techniques are growing in popularity and have been demonstrated to be a safe and effective alternative to standard glaucoma surgery. Guidance in the implementation of these procedures has been outlined.

Glaucoma - 'A Stiff Eye in a Stiff Body'

Glaucoma is a progressive, age-related optic neuropathy, whereby the prevalence increases sharply over the age of 60 and is associated with increased systemic tissue stiffness. On a molecular basis, this is associated with increased deposition of collagen and loss of elastin structure, resulting in aberrant biomechanical compliance and reduced tissue elasticity. Increased tissue stiffness is a known driver of myofibroblast activation and persistence, especially in chronic cellular injuries via mechanotransduction pathways mediated by integrins and focal adhesion kinases. Evidence from histological and imaging studies plus force measurements of glaucomatous eyes show that several ocular tissues are stiffer than normal, healthy age-matched controls including the trabecular meshwork, Schlemm's canal, cornea, sclera and the lamina cribrosa. This is associated with increased extracellular matrix deposition and fibrosis. This review reports on the evidence to support the concept that glaucoma represents 'a stiff eye in a stiff body' and addresses potential mechanisms to attenuate this.

Real-world efficacy of the intrascleral ciliary sulcus suprachoroidal microtube technique in Black and Afro-Latinx patients with glaucoma: a 1-year retrospective study

Background

Suprachoroidal surgery can lower intraocular pressure and medication use. There is currently no commercial suprachoroidal product on the market. Here, we report our 1 year results of a novel ciliary sulcus suprachoroidal microtube technique.

Purpose

To determine the real-world efficacy of intrascleral ciliary sulcus suprachoroidal microtube technique in Black and Afro-Latinx patients with glaucoma refractory to topical ocular hypertensive medications.

Methods

A retrospective non-comparative single center study of 36 Black and Afro-Latinx patients with glaucoma and pseudophakia who underwent intrascleral ciliary sulcus suprachoroidal microtube surgery for glaucoma as a stand-alone procedure at a single practice. Investigated parameters were number of medications, visual acuity (VA), intraocular pressure (IOP), mean deviation on visual field (VF) test. Success was defined as (a) IOP ⩽ 15 mmHg and or ⩾ 20% reduction in IOP and (b) a reduction in number of medications. We used paired t-test to compare baseline and follow-up parameters.

Results

We reviewed a total of 36 patients who had undergone the procedure. Twenty had success with 12-month follow-up in the study. The mean number of medications decreased significantly from 4.2 ± 1.0 preoperatively to 2.4 ± 1.7 in 12 months (p = 0.021) with five patients being medication free. In addition, the IOP decreased significantly from 21 ± 8.2 to 13.5 ± 4.4 mmHg (p = 0.032). In the 20 patients who had 12-month follow-up, the VA remained stable from Log Mar 0.62 ± 0.6-0.46 ± 0.6 (p = 0.052). VF in patients with successful procedure (no further interventions) remained stable from baseline mean deviation of -16.53 ± 10.04 to -16.82 ± 9.80 dB at 6-12 months. Adverse effects were transient and included IOP spike, hypotony, hyphema, and cornea edema that were treated and resolved.

Conclusions

This 12-month retrospective study demonstrated that intrascleral ciliary sulcus suprachoroidal microtube surgery can reduce IOP and medication burden in pseudophakic patients with glaucoma. However, despite several successes, surveillance should take place for IOP spikes, possible tube obstruction, and need for additional glaucoma surgery.

Microbiome Dysbiosis: A Pathological Mechanism at the Intersection of Obesity and Glaucoma

The rate at which obesity is becoming an epidemic in many countries is alarming. Obese individuals have a high risk of developing elevated intraocular pressure and glaucoma. Additionally, glaucoma is a disease of epidemic proportions. It is characterized by neurodegeneration and neuroinflammation with optic neuropathy and the death of retinal ganglion cells (RGC). On the other hand, there is growing interest in microbiome dysbiosis, particularly in the gut, which has been widely acknowledged to play a prominent role in the etiology of metabolic illnesses such as obesity. Recently, studies have begun to highlight the fact that microbiome dysbiosis could play a critical role in the onset and progression of several neurodegenerative diseases, as well as in the development and progression of several ocular disorders. In obese individuals, gut microbiome dysbiosis can induce endotoxemia and systemic inflammation by causing intestinal barrier malfunction. As a result, bacteria and their metabolites could be delivered via the bloodstream or mesenteric lymphatic vessels to ocular regions at the level of the retina and optic nerve, causing tissue degeneration and neuroinflammation. Nowadays, there is preliminary evidence for the existence of brain and intraocular microbiomes. The altered microbiome of the gut could perturb the resident brain-ocular microbiome ecosystem which, in turn, could exacerbate the local inflammation. All these processes, finally, could lead to the death of RGC and neurodegeneration. The purpose of this literature review is to explore the recent evidence on the role of gut microbiome dysbiosis and related inflammation as common mechanisms underlying obesity and glaucoma.

A Retrospective Comparison of Ahmed Glaucoma Valve Implants with or without Ologen Collagen Matrix

Purpose

To study the effects of Ologen collagen matrix on the outcomes of the Ahmed glaucoma valve implant.

Study Design

Retrospective case-control multicenter study, conducted at four centers, comparing the 6-month outcomes of Ahmed valve implants with or without Ologen.

Participants

The study included 125 eyes in a 4:1 pairing (25 patients with Ologen matched to 100 patients without Ologen).

Intervention

Ologen was placed over the Ahmed plate in the study group. Success was defined as an intraocular pressure (IOP) ≤ 21 mmHg either with no medication (complete success) or regardless of medications (qualified success). Other outcomes included IOP variation, eye drop use, and surgical complications.

Results

Overall, the IOP decreased from 30.72 ± 9.08 to 16.14 ± 4.79 mmHg (p=0.0001). Of the 125 eyes, 26 achieved complete success and 94 achieved qualified success. There was no difference in complete success between the groups (p=0.12); however, there was a difference in qualified success (p=0.01), with better results in the no-Ologen group (80% vs 56%). There were no differences in the decrease in medications (p=0.06), as well as the incidence of complications (p=0.69). Although the need for postoperative surgical reintervention was higher in the no-Ologen group (13% vs 4%), the difference was not significant (p=0.2).

Conclusion

The reductions in IOP and number of medications were similar in both groups after 6 months, with similar complication rates. The qualified success rate was lower in the Ologen group, but further studies are needed to clarify the role of Ologen in Ahmed valve implants.

XEN® implantation: an effective strategy to stop glaucoma progression despite prior minimally invasive glaucoma surgery

Purpose

The aim of this study was to evaluate whether XEN® implantation is a reasonable and safe method to lower the intraocular pressure (IOP) and amount of medication for adult primary open-angle glaucoma (POAG) over a 3-year period. The influence of the type of anesthesia, previous glaucoma surgery, and postoperative interventions on the outcome were examined.

Methods

In this retrospective study, 96 eyes were included. XEN® implantation was performed as sole procedure under general (n = 86) or local anesthesia (n = 10). IOP and number of glaucoma medication were assessed preoperatively: day 1, week 6, month 3, 6, 12, 24, and 36. Further outcome parameters were Kaplan–Meier success rates, secondary intervention, and complication rates.

Results

IOP decreased from 20.7 ± 5.1 to 12.8 ± 2.5 mmHg at the 36-month follow-up (p < 0.001) and glaucoma therapy was reduced from 3.3 ± 0.8 to 1.2 ± 1.6 (36 months, p < 0.001). Transient postoperative hypotony was documented in 26 eyes (27.1%). General anesthesia resulted in a significant improvement of the survival rate compared to local anesthesia (77% vs. 50%, p = 0.044). Prior iStent inject®, Trabectome®, or SLT laser had no significant impact, such as filter bleb revision. The number of postoperative needlings had a significantly negative influence (p = 0.012).

Conclusion

XEN® implantation effectively and significantly lowers the IOP and number of glaucoma therapy in POAG in the 36-month follow-up with a favorable profile of side effects and few complications. In case of IOP, general anesthesia has a significant positive influence on the survival rate, whereas prior SLT or MIGS does not have significant impact.

Relationship between blood pressure and intraocular pressure in the JPHC-NEXT eye study

Although a positive link between hypertension and intraocular pressure (IOP) has been suggested, the individual effects of systolic and diastolic blood pressure (SBP and DBP, respectively) on IOP remain unclear, particularly among Japanese populations. Here, we conducted a large-scale, cross-sectional study to determine individual and combined effects of SBP/DBP and hypertension on IOP. In total, 6783 Japanese people aged over 40 years underwent systemic and ophthalmological examinations, including measurements of blood pressure and IOP, conducted using non-contact tonometers. After adjusting for a priori known confounding factors, SBP and DBP levels were found to be positively correlated with IOP levels. The multivariable-adjusted odds ratio when comparing the hypertensive and normotensive groups for the prevalence of ocular hypertension was 1.88 (95% confidence interval, 1.14-3.08). When analysing the combined effects of SBP and DBP on ocular hypertension, SBP elevation had a greater effect on ocular hypertension than DBP increase. In conclusion, SBP and DBP levels and the prevalence of systemic hypertension were found to be positively associated with IOP levels and the prevalence of ocular hypertension in an ophthalmologically healthy Japanese population. Our findings suggest that systemic blood pressure control may be key for controlling IOP.

Ultrastructural analysis of explanted CyPass microstents and correlation with clinical findings

Purpose

The purpose of this study was to obtain insight into cellular processes after CyPass microstent implantation into the supraciliary space. With this knowledge, we expected to find some reason for surgical failure.

Methods

Nine CyPass microstents of 8 patients with primary open-angle glaucoma (n = 1), pseudoexfoliation glaucoma (n = 5), uveitic glaucoma (n = 1), and posttraumatic open-angle glaucoma (n = 1) were explanted due to recurrence of IOP elevation, corneal decompensation, or persistent hypotony. The explants were processed for light and transmission electron microscopy.

Results

Fibrotic material, consisting of collagen fibrils, microfibrils, pseudoexfoliation fibrils produced by activated fibroblasts, was detected in the stent lumen of 4/5 pseudoexfoliation glaucoma patients and also in posttraumatic open-angle glaucoma. Fibrotic material was also present on the outer surface and within fenestrations of the majority of stents. Complete absence of fibrotic reaction was noticed in 3 of 9 microstents.

Conclusion

Although MIGS is known to be less invasive than conventional surgery, implants placed in the suprachoroidal space may be adversely affected by a fibrotic tissue reaction resulting in implant failure. Understanding mechanisms and risk factors leading to fibrotic scarring following antiglaucomatous surgery may help to develop novel strategies that improve surgical outcome.

Audit of outcomes following attendance at the City West drive-through IOP glaucoma clinic during the COVID-19 pandemic

BACKGROUND

Glaucoma is the leading cause of irreversible blindness globally. During the COVID-19 pandemic, an enforced reduction in capacity resulted in the deferral of routine outpatient appointments for glaucoma patients.

AIM

This study analyses patient outcomes following the establishment of a drive-through intra-ocular pressure (IOP) clinic during the COVID-19 pandemic to alleviate increased pressure on the tertiary glaucoma services at Royal Victoria Eye and Ear Hospital (RVEEH) and Mater Misericordiae University Hospital (MMUH) between August 2020 and June 2021.

METHODS

A 1-lane driveway system was established in a marquee on the grounds of City West hotel. IOPs were measured in patients' cars using a hand held iCare100 tonometer. Results were reviewed by a consultant ophthalmologist. At hospital follow-up clinic visits, IOP was measured using the Goldmann applanation tonometer (GAT).

RESULTS

Three hundred one patients of a total of 672 who attended the drive-through clinic have subsequently attended a designated hospital follow-up appointment. In this cohort, the mean drive-through iCare IOP of 19.4 mmHg ± 6.0 was significantly higher (< 0.005) than the mean GAT IOP at the pre-drive through clinic visit (16.3 mmHg ± 3.7) and the post drive-through hospital follow-up visit (17.2 mmHg ± 4.1). Two hundred twenty-six (75%) patients did not need any treatment change, 53 (18%) required eye drop medication changes, 10 (3%) underwent a laser procedure, 4(1%) required surgical intervention, and 8 (3%) were discharged. When patient outcomes were analysed according to IOP grade assigned at the drive-through clinic, those with an iCare IOP < 21 were significantly less likely to require a treatment change. The cohort with iCare IOP ≥ 30 were significantly more likely to have a laser or surgical intervention.

CONCLUSION

The implementation of a drive-through IOP clinic was a safe and effective way to monitor glaucoma patients during COVID-19, and identify those at high risk of poor IOP control or requiring a change in treatment.

Nutritional supplementation in the prevention and treatment of Glaucoma

Glaucoma is a chronic optic neuropathy that creates a significant burden on public health. Oxidative stress is hypothesised to play a role to glaucoma progression, and its reduction is being analysed as a therapeutic target. Dietary antioxidants play a crucial role in helping provide insight into this hypothesis. We reviewed 71 trials, interventional, I -vivo and I -vitro, including 11 randomised controlled trials, to determine if adjunctive nutritional supplementation could lead to a reduction in oxidative stress and prevent glaucomatous progression. Many laboratory findings show that vitamins and natural compounds contain an abundance of intrinsic antioxidative, neuroprotective and vasoprotective properties that show promise in the treatment and prevention of glaucoma. Although there is encouraging early evidence, most clincial findings are inconclusive. The group of B vitamins appear to have the greatest amount of evidence. Other compounds such as flavonoids, carotenoids, curcumin, saffron, CoQ10, Ggngko Biloba and Resveratrol however warrant further investigation in glaucoma patients. Studies of these antioxidants and other nutrients could create adjunctive or alternative preventative and treatment modalities for glaucoma to those currently available.

Involvement of METTL3/m6Adenosine and TGFβ/Smad3 signaling on Tenon's fibroblasts and in a rabbit model of glaucoma surgery

Glaucoma filtration surgery (GFS) is a classic operation for the treatment of glaucoma, which is the second leading cause of blindness, and scar formation caused by excessive human Tenon's capsule fibroblasts (HTFs) activation is responsible for surgery failure. However, the mechanism underlying excessive HTFs activation is largely unknown. Studies have revealed that N⁶-methyladenosine (m⁶A), which is one of the most common posttranscriptional modifications, plays an important role in multiple types of cellular processes. First, we isolated and identified primary HTFs and found that transforming growth factor-β1 (TGF-β1) enhanced cell viability and promoted cell proliferation and extracellular matrix (ECM) deposition in HTFs. We subsequently found that TGF-β1 elevated the quantity of m⁶A and promoted the expression of m⁶A "writers", in the process from DNA to RNA, adenylate was methylated at the sixth N position by methylases methyltransferase-like 3 (METTL3). Furthermore, we demonstrated that METTL3 repression inhibited the promotion of cell viability, proliferation and ECM deposition in HTFs treated with TGF-β1. We then illustrated that increased METTL3 played a role by promoting Smad3 in TGF-β1-induced HTFs. We subsequently demonstrated that the METTL3/Smad3 regulatory axis was aberrantly expressed in the rabbit model of GFS. Thus, our study reveals that METTL3 indeed plays a role in modulating Smad3 in TGF-β1-induced HTFs and further provides novel theoretical strategies based on METTL3 for the inhibition of scar formation after GFS.

Cathepsin K Regulates Intraocular Pressure by Modulating Extracellular Matrix Remodeling and Actin-Bundling in the Trabecular Meshwork Outflow Pathway

The homeostasis of extracellular matrix (ECM) and actin dynamics in the trabecular meshwork (TM) outflow pathway plays a critical role in intraocular pressure (IOP) regulation. We studied the role of cathepsin K (CTSK), a lysosomal cysteine protease and a potent collagenase, on ECM modulation and actin cytoskeleton rearrangements in the TM outflow pathway and the regulation of IOP. Initially, we found that CTSK was negatively regulated by pathological stressors known to elevate IOP. Further, inactivating CTSK using balicatib, a pharmacological cell-permeable inhibitor of CTSK, resulted in IOP elevation due to increased levels and excessive deposition of ECM-like collagen-1A in the TM outflow pathway. The loss of CTSK activity resulted in actin-bundling via fascin and vinculin reorganization and by inhibiting actin depolymerization via phospho-cofilin. Contrarily, constitutive expression of CTSK decreased ECM and increased actin depolymerization by decreasing phospho-cofilin, negatively regulated the availability of active TGFβ2, and reduced the levels of alpha-smooth muscle actin (αSMA), indicating an antifibrotic action of CTSK. In conclusion, these observations, for the first time, demonstrate the significance of CTSK in IOP regulation by maintaining the ECM homeostasis and actin cytoskeleton-mediated contractile properties of the TM outflow pathway.

Metformin and Glaucoma-Review of Anti-Fibrotic Processes and Bioenergetics

Glaucoma is the leading cause of irreversible blindness globally. With an aging population, disease incidence will rise with an enormous societal and economic burden. The treatment strategy revolves around targeting intraocular pressure, the principle modifiable risk factor, to slow progression of disease. However, there is a clear unmet clinical need to find a novel therapeutic approach that targets and halts the retinal ganglion cell (RGC) degeneration that occurs with fibrosis. RGCs are highly sensitive to metabolic fluctuations as a result of multiple stressors and thus their viability depends on healthy mitochondrial functioning. Metformin, known for its use in type 2 diabetes, has come to the forefront of medical research in multiple organ systems. Its use was recently associated with a 25% reduced risk of glaucoma in a large population study. Here, we discuss its application to glaucoma therapy, highlighting its effect on fibrotic signalling pathways, mitochondrial bioenergetics and NAD oxidation.

Adenosine: The common target between cancer immunotherapy and glaucoma in the eye

Adenosine, an endogenous purine nucleoside, is a well-known actor of the immune system and the inflammatory response both in physiologic and pathologic conditions. By acting upon particular, G-protein coupled adenosine receptors, i.e., A1, A2- a & b, and A3 receptors mediate a variety of intracellular and immunomodulatory actions. Several studies have elucidated Adenosine's effect and its up-and downstream molecules and enzymes on the anti-tumor response against several types of cancers. We have also targeted a couple of molecules to manipulate this pathway and get the immune system's desired response in our previous experiences. Besides, the outgrowth of the studies on ocular Adenosine in recent years has significantly enhanced the knowledge about Adenosine and its role in ocular immunology and the inflammatory response of the eye. Glaucoma is the second leading cause of blindness globally, and the recent application of Adenosine and its derivatives has shown the critical role of the adenosine pathway in its pathophysiology. However, despite a very promising background, the phase III clinical trial of Trabodenoson failed to achieve the non-inferiority goals of the study. In this review, we discuss different aspects of the abovementioned pathway in ophthalmology and ocular immunology; following a brief evaluation of the current immunotherapeutic strategies, we try to elucidate the links between cancer immunotherapy and glaucoma in order to introduce novel therapeutic targets for glaucoma.

Microinvasive glaucoma surgery: A review of 3476 eyes

Microinvasive glaucoma surgery (MIGS) is a potentially safer and more efficacious method studied in patients with mild-to-moderate open-angle glaucoma requiring less invasive treatment goals; however, the literature on MIGS must be thoroughly evaluated. We conducted a review of MIGS by searching MEDLINE, EMBASE, and Cochrane CENTRAL. Primary efficacy indicators were reductions in intraocular pressure and topical medication use postoperatively. While all comparative randomized controlled trials assessing MIGS in English peer-reviewed journals were included, only observational studies with a target follow-up of at least one year and a high priority score were analyzed, resulting in a total of 3476 eyes across 20 trials. The mean age was 69.5 ± 2.9 years, 53.7% were female, and 77.4% were Caucasian. One study had last follow-up at less than one year, fifteen studies had follow-up extending 1-2 years, and four had longer than two years of follow-up. A pattern of more significant intraocular pressure and medication reduction was observed in patients who underwent MIGS (n = 2170) relative to control (n = 1306) interventions. iStent had the most literature supporting its efficacy, followed by Hydrus. The most common adverse events after MIGS implantation included stent obstruction, inflammation, and subsequent surgical intervention. Surgical complication rates and efficacy are favorable after MIGS. This review helps to consolidate the high-quality evidence that exists for various MIGS procedures and to identify gaps where further research is needed.

Changes of Ocular Dimensions as a Marker of Disease Progression in a Murine Model of Pigmentary Glaucoma

Purpose

The elevation of intraocular pressure (IOP), a major risk factor in glaucoma, is an important parameter tracked in experimental models of this disease. However, IOP measurement in laboratory rodents is challenging and may not correlate with some key pathological events that occur in the development of glaucoma. The aims of this study were to quantify changes in ocular morphology in DBA/2J mice that develop spontaneous, age-dependent, pigmentary glaucoma and to check the possible correlation of these parameters with IOP.

Method

Eye morphology was evaluated with MRI in DBA/2J, DBA/2J-Gpnmb⁺/SjJ, and C57BL/6J female mice ages 3, 6, 9, 12, and 15 months. The animals were anesthetized with isoflurane. A planar receive-only surface coil (inner diameter = 10 mm) was placed over each animal’s left eye and the image was acquired with a 7T small animal-dedicated magnetic resonance tomograph and T2-weighted TurboRARE sequence. Ocular dimensions were manually quantitated using OsiriX software. IOP was measured with rebound tonometry.

Results

In the control animals, no age-related changes in the ocular morphology were noted. Since 6 months of age, the anterior chamber deepening and elongation of the eyeballs of DBA/2J mice was detectable. We found a significant, positive correlation between IOP and axial length, anterior chamber area, or anterior chamber width in C57BL/6J mice but not in DBA/2J mice. However, after excluding the measurements performed in the oldest DBA/2J mice (i.e. analyzing only the animals ages 3 to 12 months), we demonstrated a significant positive correlation between IOP and anterior chamber width.

Conclusion

High-resolution magnetic resonance imaging of the eye area in mice enables reproducible and consistent measures of key dimensions of the eyeball. We observed age-dependent alterations in the eye morphology of DBA/2J mice that mostly affected the anterior chamber. We also demonstrated a correlation between some of the ocular dimensions and the IOP of C57Bl/6J mice and DBA/2J mice with moderately advanced glaucomatous pathology.

Indicators of Post-Operative Intraocular Pressure Elevation after Naïve Fluocinolone Acetonide Surgical Implantation

PURPOSE

To determine factors conferring an increased risk of developing ocular hypertension secondary to the fluocinolone acetonide (FA) sustained-release surgical implant (Retisert).

DESIGN

Retrospective, observational case series.

METHODS

Patients with a history of chronic noninfectious posterior uveitis undergoing naïve surgical FA implantation from 2007 to 2018 at the University of Colorado were studied. Patient demographics and multiple clinical measures were noted one year before and after FA implantation.

RESULTS

Twenty-nine eyes of 21 patients were studied. The median age experiencing an IOP rise vs median age experiencing no IOP rise post-FA implantation was 27.0 and 54.0 years old, respectively (p = .01). A pre-FA implant risk factor of needing future glaucoma surgery after FA implantation is prior to maximum IOP (p = .02).

CONCLUSIONS

A risk factor of elevated post-FA implantation IOP includes younger age. A potential risk factor for glaucoma surgery after FA implantation was higher maximum IOP before FA implantation.

Silencing of p53 reduces cell migration in human Tenon's fibroblasts induced by TGF-β

PURPOSE

Growth factors are considered as key molecules that participating in fibrosis formation. This research aimed to clarify potential effects of p53 on regulation of transforming growth factor β (TGF-β) and fibrosis formation and investigate the associated mechanisms.

METHODS

Vimentin was examined to identify human Tenon's fibroblasts (HTFs). p53-targeting small interfere RNA (siRNA) was synthesis and transfected into HTFs. Real-time PCR assay was utilized to evaluate p53 and microRNA-29b (miR-29b) expression. Immunocytochemical assay was used to observe TGF-β expression. The wound healing assay was conducted to evaluate migration of HTFs. Dual-luciferase assay was employed to identify interaction between p53 and miR-29b in HTFs.

RESULTS

Vimentin was extensively distributed in HTFs cells. HTFs at density of 5 × 10⁴ cells/ml and 6 days exhibited the best growth. The p53 level in TGF-β treatment group was significantly higher compared to that in blank group (p < 0.01). miR-29b level in siRNA targeting p53 group was significantly increased compared to that in blank group (p < 0.01). siRNA targeting p53 could significantly inhibit HTFs migration compared to that in single TGF-β treating HTFs group (p < 0.01). Relative luciferase activity was significantly increased in p53 overexpressed HTFs compared to that in cells transfected with empty pcDNA3.0 plasmid (p < 0.01).

CONCLUSIONS

p53 inhibited expression of TGF-β, suppressed HTFs migration and inhibited HTFs growth, by reducing miR-29b expression and interacting with miR29b gene in HTFs.

Role of the long noncoding RNA H19 in TGF-β1-induced Tenon's capsule fibroblast proliferation and extracellular matrix deposition

Glaucoma filtration surgery (GFS) is a classic surgical method used to treat glaucoma, the second leading cause of blindness. Scar formation caused by excessive Tenon's capsule fibroblast activation leads to surgical failure. However, the mechanism underlying this activation is largely unknown. In this study, we first isolated primary human Tenon's capsule fibroblasts (HTFs) and found that TGF-β promoted the viability, proliferation and extracellular matrix (ECM) deposition of HTFs. Then, we showed that TGF-β promoted the expression of H19 in HTFs and that suppression of H19 inhibited the effect of TGF-β on HTFs. Furthermore, we revealed that H19 exerted its effects by interacting with miR-200a in TGF-β-treated HTFs. Additionally, we showed that β-catenin was a target of miR-200a in TGF-β-treated HTFs. We also demonstrated that H19 acted by modulating the H19/miR-200a/β-catenin regulatory axis in TGF-β-treated HTFs. Ultimately, we found that the components of the H19/miR-200a/β-catenin regulatory axis were aberrantly expressed in a rat model of GFS. Our results show that H19 indeed acts by modulating β-catenin expression via miR-200a in TGF-β-treated HTFs, thus providing a novel rationale for the development of H19-based strategies to attenuate scar formation after GFS.

Maximum Medical Therapy: Brinzolamide/Brimonidine And Travoprost/Timolol Fixed-Dose Combinations In Glaucoma And Ocular Hypertension

Introduction

Maximal medical therapy (MMT) is the use of ≥3 classes of topical anti-glaucoma agents to achieve maximal intraocular pressure (IOP) reduction while minimizing adverse effects and compliance challenges.

Purpose

To evaluate the additive IOP-lowering effect of twice-daily brinzolamide 1%/brimonidine 0.2% fixed-dose combination (BBFC) used adjunctively with once daily travoprost 0.004%/timolol 0.5% fixed-dose combination (TTFC) in patients with open-angle glaucoma (OAG)/ocular hypertension (OHT).

Methods

In this phase IV, double-masked study, patients on TTFC for ≥28 days, aged ≥18 years, with mean IOP ≥19 and ≤28 mmHg in at least 1 eye were randomized to receive BBFC+TTFC (n=67) or vehicle+TTFC (n=67) for 6 weeks. The primary endpoint was mean change in diurnal IOP from baseline (BL, averaged over 09:00 and 11:00) at Week 6.

Results

The study was terminated prematurely due to recruitment challenges. BL mean IOP was similar in both groups (BBFC+TTFC: 21.6±1.78 mmHg; vehicle+TTFC: 21.8±1.90 mmHg). Mean change in diurnal IOP from BL at Week 6 was greater with BBFC+TTFC (−4.25 mmHg, 95% confidence interval [CI]: −4.7, −3.8) than with vehicle+TTFC (−2.11 mmHg, 95% CI: −2.6, −1.6, treatment difference, −2.15 mmHg (95% CI: −2.8, −1.5; P<0.001). Ocular adverse events (AEs) were reported in 11.9% of patients given BBFC+TTFC and 7.5% of patients given vehicle+TTFC. The AE with highest frequency was punctate keratitis (3%) in the BBFC+TTFC group; eye irritation (3%) in the vehicle+TTFC group.

Conclusion

BBFC+TTFC as MMT demonstrated clinically relevant and statistically significant reductions in mean diurnal IOP in patients with OAG/OHT. AEs were consistent with known safety profiles of individual medications.

Comparative Effectiveness and Tolerance of Subliminal Subthreshold Transscleral Cyclophotocoagulation With a Duty Factor of 25% Versus 31.3% for Advanced Glaucoma

PRéCIS:: Subliminal subthreshold transscleral cyclophotocoagulation (SS-TSCPC) with duty cycles 25% and 31.3% seems to be an effective approach to reduce intraocular pressure (IOP) in glaucoma that is refractory to medical management.

OBJECTIVE

The objective of this study was to compare the effectiveness and the tolerance of SS-TSCPC with a duty cycle of 25% versus 31.3% with Supra 810 nm Subliminal Quantel Medical laser stimulation for advanced glaucoma.

MATERIALS AND METHODS

This was a retrospective, single-center, comparative case series of patients treated by SS-TSCPC between January 2017 and July 2017. The diagnostic and inclusion criteria were patients with advanced and refractory glaucoma, defined as IOP >21 mm Hg on maximal tolerated medical therapy with or without previous glaucoma surgical procedures, a minimum follow-up of 12 months, and patients who refused or were poor candidates for additional filtering surgery or implantation of glaucoma drainage devices. The primary endpoint was surgical success defined as an IOP of 6 to 21 mm Hg or a reduction of IOP by 20% from baseline without an increase in glaucoma medication from baseline. The secondary endpoints were the mean IOP and best visual corrected acuity best-corrected visual acuity at 12 months after surgery, retreatment outcomes, glaucoma medications, and complications such as inflammation, uveitis, cataract, mydriasis, and phthisis.

RESULTS

Forty eyes of 32 patients were included: 20 eyes were subjected to SS-TSCPC with 31.3% duty cycle and 20 eyes with a 25% duty cycle. The surgical success of the TSCPC 12 months after the first procedure was better in the 31.3% duty cycle group (83.5%) than in the 25% duty cycle group (65%). The most common complications were inflammation (50%, 1 mo after surgery) and IOP spikes (increase in IOP of >25% from baseline within 1 mo of laser) in both groups. Inflammation was higher in the 31.3% duty cycle group.

CONCLUSIONS

SS-TSCPC at 31.3% and 25% duty cycle seems to be an effective approach to reduce IOP in glaucoma that is refractory to medical management. SS-TSCPC at 31.3% duty cycle is more effective than the 25% duty cycle SS-TSCPC. However, the 31.3% duty cycle SS-TSCPC induces more inflammation than the 25% duty cycle SS-TSCPC. Each procedure should be considered on a case by case basis.

Open-Angle Glaucoma: Burden of Illness, Current Therapies, and the Management of Nocturnal IOP Variation

Glaucoma is a chronic, debilitating disease and a leading cause of global blindness. Despite treatment efforts, 10% of patients demonstrate loss of vision. In the US, > 80% of glaucoma cases are classified as open-angle glaucoma (OAG), with primary open-angle (POAG) being the most common. Although there has been tremendous innovation in the surgical treatment of glaucoma as of late, two clinical variants of OAG, normal-tension glaucoma (NTG) and severe POAG, are especially challenging for providers because patients with access to care and excellent treatment options may progress despite achieving a “target” intraocular pressure value. Additionally, recent research has highlighted the importance of nocturnal IOP control in avoiding glaucomatous disease progression. There remains an unmet need for new treatment options that can effectively treat NTG and severe POAG patients, irrespective of baseline IOP, while overcoming adherence limitations of current pharmacotherapies, demonstrating a robust safety profile, and more effectively controlling nocturnal IOP.

Funding The Rapid Service Fees were funded by the corresponding author, Tanner J. Ferguson, MD.

Prophylactic treatment of intraocular pressure elevation after uncomplicated cataract surgery in nonglaucomatous eyes - a systematic review

The purpose of this systematic review was to evaluate the literature regarding prophylactic treatment of intraocular pressure (IOP) elevation after uncomplicated cataract surgery to provide an evidence-based guideline for cataract surgeons. The relevant literature was identified in EMBASE and PubMed. The risk of bias was assessed according to the 'Cochrane Handbook for Systematic Reviews of Interventions' and the ROBINS-I tool. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) criteria were used to rate the quality of evidence, and relevant data were systematically extracted to evaluate the pressure-lowering effect of the active substances. The primary outcomes for this systematic review were the absolute and relative pressure-lowering effect of the different drugs after 3-8 hr and 1 day after surgery. In total, 23 randomized controlled trials and one nonrandomized controlled study consisting of 45 treatment arms with 14 different active substances were included in the qualitative synthesis. According to the GRADE criteria, nine trials were graded as 'high' quality of evidence, 12 trials as 'moderate', while three trials were given the grade 'low' quality of evidence. The primary outcomes showed most consistency between the trials, which studied the effect of timolol, and presented a relative effect from 18.6% to 29.6% at 3-8 hr and 9.8% to 23.6% at day 1. This systematic review indicates that timolol, latanoprost and travoprost alone or medications containing timolol as an additive active substance, such as dorzolamide + timolol, brinzolamide + timolol and brimonidine + timolol, are characterized by a good relative IOP-lowering effect, which can be gained by a single dose postoperatively.

Intra-Scleral Ciliary Sulcus Suprachoroidal Microtube: Making Supraciliary Glaucoma Surgery Affordable

PURPOSE

The suprachoroidal space (SCS) has been a successful target to lower intraocular pressure (IOP) in glaucoma patients. We present the results of 4 patients who underwent a novel glaucoma surgical procedure to lower IOP: Intrascleral Ciliary Sulcus-Suprachoroidal Microtube.

METHODS

A sterile medical grade silicone microtube (Tube extender, New World Medical) was surgically placed to drain aqueous from the posterior chamber ciliary sulcus of the eye to the SCS. The internal diameter of the tube was 300 um and the length varied from 8-10mm. After informed consent was obtained and witnessed, this procedure was performed in glaucoma patients with pseudophakia. The tube was placed intrasclerally beneath an inferotemporal sclera flap (50% thickness approximately 4mm x 4mm). The anterior end of the tube was inserted into the ciliary sulcus approximately 2mm from the limbus and the posterior end was placed into the SCS approximately 4mm from the limbus. The microtube was sutured to the sclera with a 10-0 nylon suture. 8-0 vicryl sutures were used to close the sclera flap and the conjunctiva inferotemporally.

RESULTS

All 4 patients had lower IOP. The average reduction of IOP was 36% at 3 months. The amount of glaucoma medications per patient at 3 months dropped from an average of 3 to 0.25. The risks are similar to traditional glaucoma incisional surgery.

CONCLUSION

This new technique of Intrascleral Ciliary Sulcus-Suprachoroidal Microtube in all four patients with mild, moderate, and advanced glaucoma demonstrated a significant lowering of IOP and a decrease in the number of medications. Further research is required to assess long term efficacy and safety.

Nutritional supplementation in the treatment of glaucoma: A systematic review

Current treatment strategies for glaucoma are limited to halting disease progression and do not restore lost visual function. Intraocular pressure is the main risk factor for glaucoma, and intraocular pressure-lowering treatment remains the mainstay of glaucoma treatment, but even successful intraocular pressure reduction does not stop the progression of glaucoma in all patients. We review the literature to determine whether nutritional interventions intended to prevent or delay the progression of glaucoma could prove to be a valuable addition to the mainstay of glaucoma therapy. A total of 33 intervention trials were included in this review, including 21 randomized controlled trials. These suggest that flavonoids exert a beneficial effect in glaucoma, particularly in terms of improving ocular blood flow and potentially slowing progression of visual field loss. In addition, supplements containing forskolin have consistently demonstrated the capacity to reduce intraocular pressure beyond the levels achieved with traditional therapy alone; however, despite the strong theoretical rationale and initial clinical evidence for the beneficial effect of dietary supplementation as an adjunct therapy for glaucoma, the evidence is not conclusive. More and better quality research is required to evaluate the role of nutritional supplementation in glaucoma.

Effects of pre-surgical administration of prostaglandin analogs on the outcome of trabeculectomy

For primary open angle glaucoma (POAG), laser treatment or surgery is used when the target intraocular pressure (IOP) cannot be achieved by pharmacological agents, such as prostaglandin (PG) analogs; these drugs also have varied effects. We retrospectively reviewed the medical records of 74 POAG patients (74 eyes) whose IOP was inadequately controlled by PG analogs (bimatoprost [13 eyes], latanoprost [34 eyes], tafluprost [11 eyes], and travoprost [16 eyes]) and underwent primary trabeculectomy. The proportion of patients with no recurrent IOP elevation within 24 months post-trabeculectomy was significantly (P < 0.001) lower in the bimatoprost group (31.3%) than in the latanoprost (83.2%), tafluprost (45.5%), or travoprost groups (65.6%). Deepening of the upper eyelid sulcus (DUES) was observed before trabeculectomy in 18 of 74 eyes (24.3%) treated with bimatoprost (9 eyes; 50.0%), latanoprost (3 eyes; 16.7%), tafluprost (1 eye; 5.5%) and travoprost (5 eyes; 27.8%). The proportion of patients with no recurrent IOP elevation up to 24 months post-trabeculectomy was significantly (P < 0.0001) lower in the DUES(+) group (34.7%) than in the DUES(-) group (74.3%). Multivariate stepwise logistic regression analysis, with no recurrent IOP elevation used as dependent variable, and bimatoprost, latanoprost, travoprost, tafluprost, β-blocker, carbonic anhydrase inhibitor, brimonidine, gender, age, preoperative IOP, mean deviation, duration of PG analog use before surgery, and the number of ophthalmic solutions used as independent variables, identified only bimatoprost as a significant independent factor (P = 0.0368). Thus, the outcome of trabeculectomy varied depending on the PG analog used preoperatively, and bimatoprost use was associated with a high risk of recurrent IOP elevation up to 2 years post-trabeculectomy. This may indicate that the incidence of DUES differed with the PG analog used. Patients with glaucoma who are treated with bimatoprost should be monitored for DUES, and when these patients undergo trabeculectomy, the postoperative course of IOP should be followed carefully.

Role of BDNF/TrkB pathway in the visual system: Therapeutic implications for glaucoma

INTRODUCTION

Neuroprotective therapeutics are needed to treat glaucoma, an optic neuropathy that results in death of retinal ganglion cells (RGCs).

AREAS COVERED

The BDNF/TrkB pathway is important for RGC survival. Temporal and spatial alterations in the BDNF/TrkB pathway occur in development and in response to acute optic nerve injury and to glaucoma. In animal models, BDNF supplementation is successful at slowing RGC death after acute optic nerve injury and in glaucoma, however, the BDNF/TrkB signaling is not the only pathway supporting long term RGC survival.

EXPERT COMMENTARY

Much remains to be discovered about the interaction between retrograde, anterograde, and retinal BDNF/TrkB signaling pathways in both neurons and glia. An ideal therapeutic agent for glaucoma likely has several modes of action that target multiple mechanisms of neurodegeneration including the BDNF/TrkB pathway.

Two-Year COMPASS Trial Results: Supraciliary Microstenting with Phacoemulsification in Patients with Open-Angle Glaucoma and Cataracts

PURPOSE

We evaluated 2-year safety and efficacy of supraciliary microstenting (CyPass Micro-Stent; Transcend Medical, Inc., Menlo Park, CA) for treating mild-to-moderate primary open-angle glaucoma (POAG) in patients undergoing cataract surgery.

DESIGN

Multicenter (24 US sites), interventional randomized clinical trial (RCT) (ClinicalTrials.gov identifier, NCT01085357).

PARTICIPANTS

Subjects were enrolled beginning July 2011, with study completion in March 2015. Subjects had POAG with mean diurnal unmedicated intraocular pressure (IOP) 21-33 mmHg and were undergoing phacoemulsification cataract surgery.

METHODS

After completing cataract surgery, subjects were intraoperatively randomized to phacoemulsification only (control) or supraciliary microstenting with phacoemulsification (microstent) groups (1:3 ratio). Microstent implantation via an ab interno approach to the supraciliary space allowed concomitant cataract and glaucoma surgery.

MAIN OUTCOME MEASURES

Outcome measures included percentage of subjects achieving ≥20% unmedicated diurnal IOP lowering versus baseline, mean IOP change and glaucoma medication use, and ocular adverse event (AE) incidence through 24 months.

RESULTS

Of 505 subjects, 131 were randomized to the control group and 374 were randomized to the microstent group. Baseline mean IOPs in the control and microstent groups were similar: 24.5±3.0 and 24.4±2.8 mmHg, respectively (P > 0.05); mean medications were 1.3±1.0 and 1.4±0.9, respectively (P > 0.05). There was early and sustained IOP reduction, with 60% of controls versus 77% of microstent subjects achieving ≥20% unmedicated IOP lowering versus baseline at 24 months (P = 0.001; per-protocol analysis). Mean IOP reduction was ↓7.4 mmHg for the microstent group versus ↓5.4 mmHg in controls (P < 0.001), with 85% of microstent subjects not requiring IOP medications at 24 months. Mean 24-month medication use was 67% lower in microstent subjects (P < 0.001); 59% of control versus 85% of microstent subjects were medication free. Mean medication use in controls decreased from 1.3±1.0 drugs at baseline to 0.7±0.9 and 0.6±0.8 drugs at 12 and 24 months, respectively, and in the microstent group from 1.4±0.9 to 0.2±0.6 drugs at both 12 and 24 months (P < 0.001 for reductions in both groups at both follow-ups vs. baseline). No vision-threatening microstent-related AEs occurred. Visual acuity was high in both groups through 24 months; >98% of all subjects achieved 20/40 best-corrected visual acuity or better.

CONCLUSIONS

This RCT demonstrated safe and sustained 2-year reduction in IOP and glaucoma medication use after microinterventional surgical treatment for mild-to-moderate POAG.

Epigenetic Modification Prevents Excessive Wound Healing and Scar Formation After Glaucoma Filtration Surgery

PURPOSE

The purpose of this study was to determine the efficacy of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor (HDACi), in prevention of excessive wound healing and scar formation in a rabbit model of glaucoma filtration surgery (GFS).

METHODS

A rabbit model of GFS was used. Rabbits that underwent GFS received balanced salt solution, or SAHA (50 μM), or mitomycin C (0.02%). Clinical scores of IOP, bleb vascularity, and slit-lamp examination were performed. On postoperative day 14, rabbits were killed and the bleb tissues were collected for evaluation of tissue fibrosis with hematoxylin and eosin, Masson trichrome, α-smooth muscle actin (αSMA), and F-actin staining. Furthermore, SAHA-mediated acetylation of histones in corneal fibroblasts and conjunctiva were determined by Western blot analysis.

RESULTS

Suberoylanilide hydroxamic acid treatment after GFS showed no signs of edema, corneal opacity, endophthalmitis, or cataract formation. Morphometric analysis of SAHA-treated eyes showed higher bleb length (P < 0.001), bleb area (P < 0.05), lower IOP (P < 0.01), and decreased vascularity compared to control. Furthermore, SAHA treatment showed significantly reduced levels of αSMA (P < 0.001), F-actin (P < 0.01), and collagen deposition (P < 0.05) at the sclerotomy site. In addition, SAHA treatment increased the acetylation status of H3 and H4 histones in corneal fibroblasts and conjunctiva.

CONCLUSIONS

This study demonstrates that HDAC inhibition is an attractive pharmacologic target to modulate GFS wound healing, and SAHA, an HDACi, can be a useful adjunct to improve the GFS outcome.

Direct optic nerve sheath (DONS) application of Schwann cells prolongs retinal ganglion cell survival in vivo

Cell-based therapies are increasingly recognized as a potential strategy to treat retinal neurodegenerative disease. Their administration, however, is normally indirect and complex, often with an inability to assess in real time their effects on cell death and their migration/integration into the host retina. In the present study, using a partial optic nerve transection (pONT) rat model, we describe a new method of Schwann cell (SC) delivery (direct application to injured optic nerve sheath, SC/DONS), which was compared with intravitreal SC delivery (SC/IVT). Both SC/DONS and SC/IVT were able to be assessed in vivo using imaging to visualize retinal ganglion cell (RGC) apoptosis and SC retinal integration. RGC death in the pONT model was best fitted to the one-phase exponential decay model. Although both SC/DONS and SC/IVT altered the temporal course of RGC degeneration in pONT, SC/DONS resulted in delayed but long-lasting effects on RGC protection, compared with SC/IVT treatment. In addition, their effects on primary and secondary degeneration, and axonal regeneration, were also investigated, by histology, whole retinal counting, and modelling of RGC loss. SC/DONS was found to significantly reduce RGC apoptosis in vivo and significantly increase RGC survival by targeting secondary rather than primary degeneration. Both SC/DONS and SC/IVT were found to promote RGC axonal regrowth after optic nerve injury, with evidence of GAP-43 expression in RGC somas and axons. SC/DONS may have the potential in the treatment of optic neuropathies, such as glaucoma. We show that SC transplantation can be monitored in real time and that the protective effects of SCs are associated with targeting secondary degeneration, with implications for translating cell-based therapies to the clinic.

An emerging treatment option for glaucoma: Rho kinase inhibitors

Rho kinase (ROCK) inhibitors are a novel potential class of glaucoma therapeutics with multiple compounds currently in Phase II and III US Food and Drug Administration trials in the United States. These selective agents work by relaxing the trabecular meshwork through inhibition of the actin cytoskeleton contractile tone of smooth muscle. This results in increased aqueous outflow directly through the trabecular meshwork, achieving lower intraocular pressures in a range similar to prostaglandins. There are also animal studies indicating that ROCK inhibitors may improve blood flow to the optic nerve, increase ganglion cell survival, and reduce bleb scarring in glaucoma surgery. Given the multiple beneficial effects for glaucoma patients, ROCK inhibitors are certainly a highly anticipated emerging treatment option for glaucoma.