Clinical investigation of new glaucoma procedures

PRESERFLO ™ MicroShunt versus trabeculectomy: 1-year results on efficacy and safety

PURPOSE

To compare the efficacy and safety of the PRESERFLO™ MicroShunt versus trabeculectomy in patients with primary open-angle glaucoma (POAG) after one year.

PATIENTS AND METHODS

Institutional prospective interventional cohort study comparing eyes with POAG, which had received the PRESERFLO™ MicroShunt versus trabeculectomy. The MicroShunt group was matched with the trabeculectomy group for age, known duration of disease, and number and classes of intraocular pressure (IOP) lowering medications to have similar conjunctival conditions. The study is part of the Dresden Glaucoma and Treatment Study, using a uniform study design, with the same inclusion and exclusion criteria, follow-ups and standardized definitions of success and failure for both procedures.

PRIMARY OUTCOME MEASURES

mean diurnal IOP (mdIOP, mean of 6 measurements), peak IOP, and IOP fluctuations.

SECONDARY OUTCOME MEASURES

success rates, number of IOP lowering medications, visual acuity, visual fields, complications, surgical interventions, and adverse events.

RESULTS

Sixty eyes of 60 patients, 30 in each group, were analyzed after 1-year follow-ups. Median [Q25, Q75] mdIOP (mmHg) dropped from 16.2 [13.8-21.5] to 10.5 [8.9-13.5] in the MicroShunt and from 17.6 [15.6-24.0] to 11.1 [9.5-12.3] in the trabeculectomy group, both without glaucoma medications. Reduction of mdIOP (P = .596), peak IOP (P = .702), and IOP fluctuations (P = .528) was not statistically significantly different between groups. The rate of interventions was statistically significantly higher in the trabeculectomy group, especially in the early postoperative period (P = .018). None of the patients experienced severe adverse events.

CONCLUSION

Both procedures are equally effective and safe in lowering mdIOP, peak IOP and IOP fluctuations in patients with POAG, one year after surgery.

CLINICAL TRIAL REGISTRATION

NCT02959242.

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.

Challenges in the complex management of post-keratoplasty glaucoma

Glaucoma is a serious complication after corneal transplantation and itself a common cause for graft failure and leading cause of vision loss post-keratoplasty due to corneal endothelial decompensation. Endothelial keratoplasty procedures like Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) may be superior to penetrating keratoplasty (PK) regarding the incidence of elevated intraocular pressure (IOP) and development of glaucoma. There are indications that regardless of the method of keratoplasty, some corneal diseases like pseudophakic bullous keratopathy, corneal perforation, and graft rejection have a higher risk for developing post-keratoplasty glaucoma than keratoconus and corneal dystrophies and likewise respond less to IOP lowering therapy. In this review, the pathophysiology of post-keratoplasty glaucoma, the diagnostic tools with focus on different devices, and their limitations with regard to measuring IOP and the treatment modalities are presented.

Deconstructing aqueous humor outflow - The last 50 years

Herein partially summarizes one scientist-clinician's wanderings through the jungles of primate aqueous humor outflow over the past ~45 years. Totally removing the iris has no effect on outflow facility or its response to pilocarpine, whereas disinserting the ciliary muscle (CM) from the scleral spur/trabecular meshwork (TM) completely abolishes pilocarpine's effect. Epinephrine increases facility in CM disinserted eyes. Cytochalasins and latrunculins increase outflow facility, subthreshold doses of cytochalasins and epinephrine given together increase facility, and phalloidin, which has no effect on facility, partially blocks the effect of both cytochalasins and epinephrine. H-7, ML7, Y27632 and nitric oxide - donating compounds all increase facility, consistent with a mechanosensitive TM/SC. Adenosine A1 agonists increase and angiotensin II decrease facility. OCT and optical imaging techniques now permit visualization and digital recording of the distal outflow pathways in real time. Prostaglandin (PG) F2α analogues increase the synthesis and release of matrix metalloproteinases by the CM cells, causing remodeling and thinning of the interbundle extracellular matrix (ECM), thereby increasing uveoscleral outflow and reducing IOP. Combination molecules (one molecule, two or more effects) and fixed combination products (two molecules in one bottle) simplify drug regimens for patients. Gene and stem cell therapies to enhance aqueous outflow have been successful in laboratory models and may fill an unmet need in terms of patient compliance, taking the patient out of the delivery system. Functional transfer of genes inhibiting the rho cascade or decoupling actin from myosin increase facility, while genes preferentially expressed in the glaucomatous TM decrease facility. In live NHP, reporter genes are expressed for 2+ years in the TM after a single intracameral injection, with no adverse reaction. However, except for one recent report, injection of facility-effective genes in monkey organ cultured anterior segments (MOCAS) have no effect in live NHP. While intracameral injection of an FIV. BOVPGFS-myc.GFP PGF synthase vector construct reproducibly induces an ~2 mmHg reduction in IOP, the effect is much less than that of topical PGF2⍺ analogue eyedrops, and dissipates after 5 months. The turnoff mechanism has yet to be defeated, although proteasome inhibition enhances reporter gene expression in MOCAS. Intracanalicular injection might minimize off-target effects that activate turn-off mechanisms. An AD-P21 vector injected sub-tenon is effective in 'right-timing' wound healing after trabeculectomy in live laser-induced glaucomatous monkeys. In human (H)OCAS, depletion of TM cells by saponification eliminates the aqueous flow response to pressure elevation, which can be restored by either cultured TM cells or by IPSC-derived TM cells. There were many other steps along the way, but much was accomplished, biologically and therapeutically over the past half century of research and development focused on one very small but complex ocular apparatus. I am deeply grateful for this award, named for a giant in our field that none of us can live up to.

Comparing Medium-Term Clinical Outcomes following XEN® 45 and XEN® 63 Device Implantation

Purpose

To evaluate medium-term clinical outcomes with XEN® 45 or XEN® 63 Gel Stent (Allergan, Dublin, Ireland) for treatment of primary open angle glaucoma (POAG). Materials and Methods. Retrospective, descriptive, and observational study involving 40 patients implanted with a XEN® 45 Gel Stent and 34 implanted with a XEN® 63 Gel Stent who had undergone POAG surgery and had been followed up and controlled between 12 and 36 months.

Results

IOP dropped from 18.02 ± 5.23 mmHg preop to 13.81 ± 1.88, 14.80 ± 2.23, and 14.62 ± 1.90 at 1, 2, and 3 years after surgery (p < 0.001) consecutively with XEN® 45 and from 19.00 ± 6.11 mmHg preop to 15.47 ± 2.45, 14.66 ± 2.45, and 15.46 ± 2.48 at 1, 2, and 3 years after surgery (p < 0.001) with XEN® 63. The number of drugs used by patients to treat their glaucoma decreased after undergoing surgery in both groups. Within the XEN® 45 group, mean changes at 1 year, 2 years, and 3 years amounted to 70%, 74.3%, and 37.5%, respectively, whereas within the XEN® 63 group, the mean reduction was 75%, 79.8%, and 71.9%. When comparing the outcomes for two groups, the differences did not prove to be statistically significant. More than 90% of the procedures included in the study (using either gel-stent device) were completed without any noteworthy complications.

Conclusion

POAG surgical procedures with either XEN® 45 or XEN® 63 Gel Stent implantation could be a safe and effective treatment approach.

Medium-term clinical outcomes following Xen45 device implantation

PURPOSE

To evaluate medium-term clinical outcomes with microstent XEN^® 45 Gel Stent (Allergan Dublin, Ireland) for treatment of primary open-angle glaucoma (POAG).

MATERIAL AND METHODS

This is a retrospective, descriptive and observational study involving 93 eyes from 63 patients who had undergone POAG surgery with a XEN^® 45 Gel Stent implantation and had been followed up and controlled between 12 and 36 months.

RESULTS

IOP dropped from 18.23 ± 5.00 mmHg pre-op to 14.16 ± 2.14, 14.47 ± 2.16 and 14.63 ± 1.91 at 1, 2 and 3 years after surgery (p = 0.000, 0.000 and 0.001) consecutively. Mean number of medications dropped from 1.87 ± 0.94 preoperatively to 0.31 ± 0.69, 0.34 ± 0.63 and 1.00 ± 0.88 (p = 0.000, 0.000 and 0.017) at 12, 24 and 36 months. Mean visual field deviation values never turned out to be significant for any of the follow-up visit data. A total of 94.6% of the surgical procedures turned out to be complication-free. In one surgery, the procedure failed and 18 months later other device was implanted.

CONCLUSION

POAG surgical procedures with XEN^® 45 Gel Stent implants are a safe and effective treatment approach.

Needling With 5-Fluorouracil (5-FU) After XEN Gel Stent Implantation: 6-Month Outcomes

PURPOSE

The purpose of this study was to evaluate frequency, safety, and efficacy of needling in patients that underwent XEN Gel Stent implantation.

METHODS

Retrospective case review of 19 eyes of 57 consecutive patients (61 eyes) with primary open-angle glaucoma or pseudoexfoliative glaucoma that previously underwent implantation of XEN45 alone or in combination with cataract surgery followed by needling procedure with 5-FU. Success was defined at 2 IOP levels: ≤21 mm Hg and ≤15 mm Hg, with or without additional glaucoma medications. Treatment failure was defined as IOP>21 mm Hg or <5 mm Hg, need for additional glaucoma surgery or loss of light perception.

RESULTS

Totally 19 of 61 eyes that underwent XEN gel implantation had subsequent needling and were included. Preneedling IOP was 26.2±9.5 and postneedling IOP at last follow-up 15.4±3.7 mm Hg (P=0.0001). Overall success rates of 17 (90%) and 13 eyes (69%) were observed at the ≤21 mm Hg and ≤15 mm Hg level, respectively. Preneedling and postneedling visual acuity and number of medications remained unchanged (P>0.05). Two eyes (10%) were categorized as treatment failures. No major complications occurred. Mean follow-up was 203.8±142.2 (range, 22 to 456) days.

CONCLUSIONS

Needling revision following XEN gel stent implantation showed a good IOP-lowering effect without significant increase in number of antiglaucoma medications, decrease in visual acuity, nor any major complications. Further studies with long-term follow-up and a larger number of patients are needed to fully assess the safety and efficacy of this procedure.

Ab interno canaloplasty combined with trabecular bypass stenting in eyes with primary open-angle glaucoma

Purpose

Evaluate outcomes of trabecular meshwork (TM) bypass (iStent^® GTS100) with cataract extraction (CE) and TM-bypass + ab interno canaloplasty (CP) (VISCO360^®) with CE in patients with primary open-angle glaucoma (POAG).

Setting

Private surgical center for a comprehensive ophthalmology practice

Design

Retrospective analysis of 186 eyes from 130 consecutive patients with 6 months follow-up.

Methods

Eligible eyes had POAG, indicated for CE, and had received CE + TM-bypass or CE + TM-bypass + CP. Exclusions: glaucomas not POAG, SLT within 6 months, or previous ALT. IOP, visual acuity, and medication use assessed at baseline, months 1, 3, and 6. Endpoints were mean reduction in IOP from baseline at 6 months, proportion with IOP reduction at 6 months of ≥20% and IOP <18 mmHg on same or fewer medications, mean medication reduction, and proportion medication independent.

Results

Eighty-six eyes comprised the CE + TM-bypass + CP group; 100 eyes in the CE + TM-bypass group. At 6 months: mean IOP reduction was 2.9±3.6 mmHg for CE + TM-bypass + CP and 1.7±3.1 mmHg for CE + TM-bypass group (P<0.05); the proportion with IOP reduction of ≥20% and an IOP <18 mmHg on the same or fewer medications was 46% for CE + TM-bypass + CP and 35% for CE + TM-bypass; for both CE + TM-bypass + CP and CE + TM-bypass, mean number of medications was decreased (0.9 and 0.7, P<0.0001) with 56% and 48% off all medication. The most common AE were inflammation (6%) for CE + TM-bypass + CP group and VA loss (8%) for CE + TM-bypass.

Conclusion

At six months, a greater proportion of CE + TM-bypass + CP patients achieved IOP reduction of ≥20% and an IOP <18 mmHg on the same or fewer medications than for TM-bypass + CE.

XEN Implant for Glaucoma Treatment: A Review of the Literature

PURPOSE

The purpose of this review is to summarize current knowledge on XEN implant for the treatment of glaucoma.

METHODS

A comprehensive literature review has been performed regarding XEN implant and its use on glaucoma management. Forty-two articles were checked and 37 were found to be relevant. Out of them, 21 were excluded as being case reports and reviews and the remaining 16 were eligible for the purpose of our review.

RESULTS

There was a significant reduction in intraocular pressure as well as in the number of medications needed in glaucoma patients treated with XEN implant either alone or combined with cataract surgery. In addition, combination of XEN implant with Baerveldt tubes has been shown to be beneficial in cases of refractory glaucoma, although complications may be present in this technique. Moreover, uveitic glaucoma may be a potential application of XEN implant.

CONCLUSIONS

XEN implant devices have been developed as a surgical alternative for glaucomatous patients and are expected to play an important role in the management of glaucoma in the future.

The Role of Minimally Invasive Glaucoma Surgery Devices in the Management of Glaucoma

SIGNIFICANCE

Noncompliance is a problem affecting glaucoma patients. Approaches to improve adherence include the use of drug-delivery systems and safer forms of surgery. Minimally invasive glaucoma surgery (MIGS) has reduced complications, particularly in combination with cataract surgery, and with its good intraocular pressure (IOP) reduction may reduce or eliminate glaucoma medications.Glaucoma is a progressive disease and a leading cause of irreversible blindness. Elevated IOP is the most important risk factor, but effective medical management is dependent on patient adherence. This review summarizes the adherence problem in glaucoma and the efforts, including MIGS, to provide effective IOP control that is not dependent on patient compliance.The current understanding of patient adherence to pharmacological treatment of glaucoma is discussed including the challenges facing glaucoma patients. Historical approaches to providing IOP control in a sustained and reliable way are presented culminating in a review of the burgeoning use of MIGS devices.It is estimated that, in the United States, 27% of prescriptions written, across all medications, are not filled or are filled but not taken. For ocular hypotensive medications, even when filled, a large percentage (which varies widely by study) are not instilled as prescribed. To address this problem, methods for sustained drug delivery have been and continue to be developed, as well as surgical and laser approaches. Most recently, MIGS devices have gained popularity because of the ease of implantation during cataract surgery, favorable safety profile, and the possibility for effective and long-lasting IOP lowering, as well as the reduction or elimination of need for IOP-lowering medication.Poor adherence to treatment is relatively common among glaucoma patients and is associated with progression of disease. Recommending MIGS implantation during cataract surgery may offer optometrists a valuable treatment option in managing glaucoma patients, particularly where good adherence is in doubt.

Identifying the predictors of needling after XEN gel implant

PURPOSE

To identify factors associated with probability of needling after XEN implant.

METHODS

Analysis of data from prospective case series of patients with standalone XEN implant or combined XEN + cataract. Primary outcome was to determine whether postoperative day 1 and week 1 intraocular pressure (IOP), type of glaucoma, and glaucoma severity affected probability and number of needling interventions required.

RESULTS

A total of 149 eyes of 113 patients were included in the analysis. In the XEN alone group, mean IOP at day 1 and week 1 was 9.70 ± 5.43 and 10.33 ± 4.41 mmHg, respectively. Eyes with lower IOP on day 1 were less likely to require needling (Odds ratio; OR, 1.14; 95% CI, 1.02-1.28; p = 0.02). A similar association (OR, 1.15; 95% CI, 1.06-1.26; p = 0.001) was observed between day 1 IOP in and number of needling interventions. In the XEN + cataract group, mean IOPs at day 1 and week 1 were 13.75 ± 7.52 and 11.81 ± 5.36 mmHg, respectively. No significant association was noted between early postoperative IOP and probability or number of needling in this group. With IOP > 20 mmHg the probability of needling was ~ 80%. This number decreased to 35% if day 1 IOP was < 10 mmHg.

CONCLUSION

Postoperative day 1 IOP is a predictor for needling in patients undergoing standalone XEN implantation. These results suggest that surgeons should not wait too long to intervene via needling if IOP in the early postoperative period is in the high teens or above. Type or severity of glaucoma did not influence the probability of needling or number of needling interventions required.

Discovery, characterization and clinical utility of prostaglandin agonists for the treatment of glaucoma

Topical ophthalmic formulations of analogues of the endogenous arachidonic acid cyclooxygenase metabolite, PGF_2α , are the standard of care treatment for the blinding disease glaucoma. These are the most potent and efficacious medical therapies for lowering intraocular pressure (IOP), the most important risk factor identified for disease progression. They have few side effects and offer the convenience of once-a-day dosing. It was initially believed that endogenous PGs raised IOP and caused substantial ocular surface adverse effects. However, carefully designed experiments demonstrated that esterification of the carboxylic acid afforded potent and efficacious topical ocular hypotensive activity. The final hurdle to be overcome was improvement of the side effect profile. A hypothesis was advanced that the IOP-lowering effect of PGF_2α isopropyl ester was due to activation of its cognate PG-FP receptor, while side effects were largely due to promiscuous interaction with other PG receptors. This hypothesis was validated by modification of the ω chain (carbons 13-20) to a phenyl group. This provided the first marketed FP-class PG agonist analogue (FP-PGA) ocular hypotensive agent, latanoprost. Since the introduction of latanoprost into clinical medicine to lower and control IOP, a number of additional FP-PGAs have been discovered, characterized and marketed, including travoprost, tafluprost, unoprostone isopropyl ester and bimatoprost (an amide). LINKED ARTICLES: This article is part of a themed section on Eicosanoids 35 years from the 1982 Nobel: where are we now? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.8/issuetoc.

The effect of trabeculectomy on serum brain-derived neurotrophic factor levels in primary open-angle glaucoma

PURPOSE

We aimed to investigate the effect of trabeculectomy on serum brain-derived neurotrophic factor (BDNF) levels. Our secondary goal was to compare serum and aqueous humor (AH) BDNF levels in primary open-angle glaucoma (POAG) and control subjects.

METHODS

This prospective, cross-sectional study consists of 20 eyes of with advanced-stage POAG who had trabeculectomy and 19 eyes of age- and sex-matched control healthy subjects who had cataract surgery. Serum and AH samples were obtained preoperatively in trabeculectomy group and control subjects. Serum samples were obtained at the third postoperative month in both groups.

RESULTS

The aqueous humor and serum levels of BDNF at the surgery day were found to be strongly positive correlated (r = 0.868; p < 0.001). Serum and AH BDNF levels of POAG cases were significantly lower than control subjects at the surgery day (respectively p = 0.038, p = 0.011). In POAG cases, serum BDNF levels significantly increased at the third month after trabeculectomy while there was not a significant difference in control subjects with cataract surgery (p < 0.001; p = 0.717 respectively).

CONCLUSION

Trabeculectomy was found to have a positive effect on serum BDNF levels in POAG cases.