Ab Interno Trabeculectomy Versus Trabeculectomy for Open-Angle Glaucoma

Surgical Outcomes of Ab Interno Trabeculotomy Without Phacoemulsification

Purpose

The aim of this study was to evaluate ab interno trabeculotomy outcomes without phacoemulsification.

Methods

This retrospective study evaluated 118 eyes of patients aged 18 and above who underwent ab interno trabeculotomy between December 2017 and August 2022. When surgeries were performed in both eyes, only the eye undergoing the initial surgery was evaluated. Prior to and after surgery, the intraocular pressure (IOP) and mean number of IOP-lowering medications were compared. An IOP of ≤21 mmHg (A) and ≤18 mmHg (B) along with a ≥20% reduction in the preoperative IOP was defined as survival. Cases that required reoperation for glaucoma were defined as surgical failure. The Kaplan-Meier method was used to evaluate the survival rates. A Cox proportional hazards model was used to analyze the preoperative factors that influenced survival rates.

Results

At 36 months postoperatively, the 13.4 ± 2.8 mmHg average IOP was significantly decreased from the preoperative 23.5 ± 9.8 mmHg value (P < 0.0001). Moreover, a significant decrease in the mean number of the IOP-lowering medications to 2.3 ± 1.4 at 36 months was found versus the initial 3.9 ± 1.1 preoperative value (P < 0.0001). The survival rates for criteria A and B at 36 months postoperatively were 28% and 25%, respectively. Only the preoperative IOP was identified by multivariate analysis as a factor influencing survival rates (P < 0.0001). Hyphema in 36 eyes (30.5%) and an IOP spike in 20 eyes (16.9%) were the only observed complications. Additional glaucoma surgery was required in 27 eyes (22.9%) during the follow-up period.

Conclusion

Utilization of ab interno trabeculotomy effectively lowered the IOP and reduced the number of IOP-lowering medications. Patients with higher preoperative IOP exhibited better postoperative outcomes.

Comparison of Short-term Visual Acuity Changes After Trabeculotomy ab Interno Using Trabectome and Trabeculectomy ab Externo

PURPOSE

To compare short-term visual acuity (VA) changes after trabeculotomy ab interno (TAI) using trabectome and trabeculectomy ab externo (TAE) performed on pseudophakic eyes.

DESIGN

A single-center retrospective study.

PARTICIPANTS

Patients with pseudophakic eyes who had primary open-angle glaucoma or exfoliation glaucoma and underwent TAI or TAE alone.

METHODS

Changes in intraocular pressure (IOP), medication score, Snellen VA, and the number of eyes with vision loss (loss of ≥ 2 Snellen lines) were evaluated at baseline, week 1, and months 1, 3, and 6. The risk factors for vision loss at 6 months postoperatively were analyzed in both groups.

MAIN OUTCOME MEASURES

Visual acuity changes.

RESULTS

A total of 112 eyes of 112 patients were examined: 46 in the TAI group and 66 in the TAE group. Intraocular pressure was significantly lower in both groups at each visit than at baseline. The TAI group had a significantly higher mean postoperative IOP than the TAE group. Medication scores in the TAI group were significantly different after 3 months compared with baseline; however, decreased significantly at all study visits in the TAE group. The mean VA in the TAI group did not decrease significantly at each visit. In the TAE group, it decreased significantly up to 3 months but was not significantly different at 6 months. At all study visits, the number of eyes with vision loss was significantly lower in the TAI group than in the TAE group. Only 2 eyes in the TAI group (4.3%) had vision loss at 6 months, which was caused by macular edema. In the TAE group, 13 eyes (19.7%) experienced vision loss at 6 months. In all cases, the presence of preoperative split fixation [odds ratio = 7.30, P < 0.05] and the occurrence of hypotony-related complications [odds ratio = 6.76, P < 0.05] within 6 months were risk factors for vision loss.

CONCLUSIONS

TAI lowered IOP less than TAE; however, there was less vision loss with TAI. For eyes with a target IOP in the mid-teens, TAI can be recommended as initial surgery.

FINANCIAL DISCLOSURE(S)

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

[Real-world outcomes of glaucoma surgical procedures for open-angle glaucoma]

This article provides an overview of real-world outcomes in glaucoma surgical procedures. While randomized clinical trials provide valuable insights, they do not fully reflect real-world clinical practice. Real-world studies enable the evaluation of outcomes in uncontrolled settings and play a crucial role in counselling and decision-making for glaucoma treatment. By examining real-world data the article aims to identify rare adverse events that may go unnoticed in controlled clinical trials. The focus is on assessing the effectiveness and safety of glaucoma surgical procedures beyond the controlled trial setting.

Favorable effect of ripasudil use on surgical outcomes of microhook ab interno trabeculotomy

PURPOSE

We have previously demonstrated that prolonged use of glaucoma medications was associated with a poor surgical outcome of ab interno trabeculotomy (µTLO). Given that almost all types of glaucoma eye drop either enhance the drainage through the uveoscleral pathway or reduce aqueous humor production, we hypothesized that prolonged use of these medications might cause disuse atrophy of the conventional pathway. In contrast, ripasudil increases the conventional outflow and eventually shows a favorable outcome of µTLO. This study aimed to evaluate the effect of ripasudil use on µTLO outcomes.

METHOD

The medical charts of 218 patients who underwent µTLO were analyzed retrospectively. We compared the 1-year outcome between ripasudil users versus nonusers by using propensity score matching. We set the covariates as age, sex, glaucoma types, preoperative intraocular pressure (IOP), the mean deviation values of visual field tests, the presence or absence of concomitant cataract surgery, trabecular meshwork incision range, the presence or absence of any glaucoma medication except ripasudil and duration of glaucoma medical therapy. Success was defined as a postoperative IOP between 5 and 21 mmHg, a ≥ 20% IOP reduction from baseline, and no additional glaucoma surgery at postoperative 1 year.

RESULT

Fifty-seven patients each were allocated to the ripasudil users or nonusers. The 1-year success rates were 74% in ripasudil users and 51% in nonusers (p = 0.01). Kaplan‒Meier survival curves also showed that the ripasudil users had a higher survival distribution (p = 0.01).

CONCLUSION

The patients who took ripasudil showed a favorable 1-year outcome of µTLO.

Six year outcomes of combined phacoemulsification surgery and endoscopic cyclophotocoagulation in refractory glaucoma

PURPOSE

This study is to describe the 6-year results of combined phacoemulsification surgery and endoscopic cyclophotocoagulation (Phaco-ECP) surgery in patients with uncontrolled glaucoma and no previous glaucoma surgery.

METHODS

This is a retrospective case series of 84 eyes. The primary outcome measure was intraocular pressure (IOP) reduction 6 years postoperatively. Secondary outcome measures were the cumulative probability of failure of the surgical procedure at 6 years. Failure was defined as IOP higher than 21 mm Hg or lower than 6 mm Hg or IOP not reduced by 20% from baseline at the 1, 2, 3, 4, 5, or 6-year time points or further laser or other surgery to reduce IOP at any timepoint.

RESULTS

There was a statistically significant decrease in mean IOP from 18.9 mmHg pre-operatively to 13.7, 12.8, 13.0, 12.7, 12.5, and 12.3 mmHg at the 1, 2, 3, 4, 5, and 6 years post-operatively respectively (p < 0.001). Fifty-seven (68%) reached criteria for failure by 6 years. In 36% of cases, this was due to inadequate IOP control, whereas 32% required further laser or surgery. When we excluded patients who only had selective laser trabeculoplasty rather than further surgery, the failure rate reduced to 51%. Eleven percent had a post-operative complication, 2.4% requiring further surgical intervention.

CONCLUSIONS

At 6 years postoperatively, combined phaco-ECP achieved a significant reduction in IOP in patients with uncontrolled glaucoma and no previous drainage surgery. Significant complications were uncommon, but 68% was classified as surgical failures by the six year point.

Trabeculectomy: Does It Have a Future?

The trabeculectomy (TRAB) procedure has undergone various modifications to increase the long-term surgical success and safety profiles. The main issues with TRAB include short and long-term complications, that are more common with the concomitant use of anti-fibrotic agents. While many surgeons have predicted the demise of trabeculectomy amidst newer non-penetrating glaucoma surgeries, it is still the gold standard procedure for patients with an advanced or rapidly progressing disease and for those patients who need very low intraocular pressures. This review article is unique in summarizing the evolution of trabeculectomy and its efficacy compared to neoteric shunt procedures while trying to predict if trabeculectomy has a future in the modern surgical world. We have compared the outcomes and complications of trabeculectomy to all the surgical procedures available to date and have tried to evolve an algorithm to help surgeons to decide on their preferred technique.

Morphological changes to Schlemm's canal and the distal aqueous outflow pathway in monkey eyes with laser-induced ocular hypertension

Though roughly 30-50% of aqueous outflow resistance resides distal to Schlemm's canal (SC), the morphology of the conventional outflow pathway distal to SC has not been thoroughly evaluated. This study examined the morphological changes along proximal and distal aspects of the conventional aqueous outflow pathway and their association with decreased outflow facility in an experimental model of glaucoma in cynomolgus macaques. Nd:YAG laser burns were made to 270-340 degrees of the trabecular meshwork (TM) of one eye (n = 6) or both eyes (n = 2) of each monkey to induce ocular hypertension. Distinct regions of the TM were left unlasered. Contralateral eyes (n = 5) were not lasered and were utilized as controls. Monkeys were sacrificed ≥58 months after their last laser treatment. All eyes were enucleated and perfused at 15 mmHg for 30 min to measure outflow facility. Two pairs of eyes were also perfused with fluorescein to examine segmental outflow. All eyes underwent perfusion-fixation for 1 h. Anterior segments were cut into radial wedges and processed for light and electron microscopy. Width, height, and cross-sectional area (CSA) of SC were compared between high- and low-flow regions of control eyes, and between non-lasered regions of laser-treated eyes and control eyes. Number and CSA of intrascleral veins (ISVs) were compared between non-lasered and lasered regions of laser-treated eyes and control eyes, and between high- and low-flow regions of control eyes. Scleral collagen fibril diameter was compared between control eyes and lasered and non-lasered regions of laser-treated eyes. Median outflow facility was significantly decreased in laser-treated eyes compared to control eyes (P = 0.02). Median CSA and height of SC were smaller in high-flow regions than low-flow regions of control eyes (P < 0.05). Median width of SC was not significantly different between high- and low-flow regions of control eyes (P > 0.05). Median CSA, width, and height of SC were not different between non-lasered regions and control eyes (P > 0.05). SC was partially or completely obliterated in lasered regions. Median number of ISVs was significantly decreased in lasered regions compared to non-lasered regions (P < 0.01) and control eyes (P < 0.01). Median CSA of ISVs did not differ between these groups (P > 0.05). Median number and CSA of ISVs were not significantly different between high- and low-flow regions of control eyes (P > 0.05). Lasered regions displayed looser scleral stroma and smaller median diameter of collagen fibrils adjacent to the TM compared to non-lasered regions (P < 0.05) and control eyes (P < 0.05). Dense TM, partial to complete obliteration of SC, and a decreased number of patent ISVs may account in part for the decreased outflow facility in monkey eyes with laser-induced ocular hypertension. The significance of changes in scleral structure in laser-treated eyes warrants further investigation.

A novel use of the endoscopic cyclophotocoagulative probe for the management of excisional goniotomy induced chronic recurrent hyphema

Purpose

To describe the management of a case of chronic, recurrent hyphema following excisional goniotomy with the Kahook Dual Blade.

Observations

One week following uncomplicated surgery, the patient presented with eye pain, elevated intraocular pressure, and layered hyphema. The hyphema resolved with conservative measures but recurred several times with similar symptoms over the next several months. An attempt to stenose the "oozing" collector channel using the argon laser was unsuccessful. Treatment of the angle with an endoscopic semi-conductor diode laser (endoscopic cyclophotocoagulative or ECP) probe successfully altered the angle preventing further episodes of recurrent hyphema. The primary glaucoma procedure failed necessitating a filtering procedure.

Conclusions and importance

Clinician should be aware of this potential complication, its treatment options, and outcomes.

Long-Term Outcomes of a Kahook Dual Blade Procedure Combined with Phacoemulsification in Japanese Patients with Open-Angle Glaucoma

We retrospectively evaluated the long-term surgical outcomes of phacoemulsification combined with a Kahook dual blade (KDB) procedure in Japanese patients with open-angle glaucoma. The primary outcome was surgical success or failure. Surgical failure was indicated by a <20% reduction in preoperative intraocular pressure (IOP) or IOP > 18 mmHg (criterion A), IOP > 14 mmHg (criterion B), or requirement for reoperation. Glaucoma medications after surgery and postoperative complications were recorded. Surgical outcomes were compared between primary open-angle glaucoma (POAG) and exfoliation glaucoma (ExG) groups. The probability of success at 36 months postoperation was 52.5% using criterion A and 36.9% using criterion B. Mean IOP decreased significantly from 19.5 ± 6.9 mmHg preoperatively to 11.9 ± 2.7 mmHg at 36 months, and the mean number of glaucoma medications from 2.4 ± 1.4 to 1.6 ± 1.4 (both p < 0.01). IOP spikes were significantly more common in the ExG group (23.7% vs. 9.1%; p = 0.045), as was the need for additional glaucoma surgery (10.5% vs. 1.8%; p = 0.038). A KDB procedure combined with cataract surgery resulted in significant long-term decreases in IOP and the number of glaucoma medications. The complication rate was higher in eyes with ExG. Therefore, these eyes require more careful management after a KDB procedure.

Association of the prolonged use of anti-glaucoma medications with the surgical failure of ab interno microhook trabeculotomy

PURPOSE

This study examined the perioperative factors affecting surgical success in ab interno microhook trabeculotomy (μTLO).

METHODS

A total of 146 consecutive patients who underwent μTLO were included in this retrospective study. We performed Cox proportional hazard modelling by setting surgical success at 1 year as an objective variable. The explanatory variables included age, sex, glaucoma type, preoperative intraocular pressure (IOP), glaucoma drug score, mean deviation (MD) of the Humphrey visual field test, duration of glaucoma drug use, antithrombotic drug use, combined cataract surgery, incision range and diabetes mellitus. Additionally, we performed 1:1 matching using propensity score analysis and compared the perioperative parameters between durations of glaucoma drug use of <4.5 years and ≥ 4.5 years (50 patients each). We defined surgical success as satisfaction of all three criteria: IOP 5-21 mmHg, IOP reduction of ≥20% from the preoperative IOP and no additional glaucoma surgery.

RESULTS

The Cox proportional hazard model revealed that a longer duration of anti-glaucoma medication was significantly associated with surgical failure. Propensity score matching analysis showed that the <4.5-year users of anti-glaucoma drugs had significantly higher success rates than the ≥4.5-year users (72% versus 52%; p = 0.04).

CONCLUSIONS

The prolonged use of multiple glaucoma drugs adversely affected the outcome of μTLO at least at 1 year postoperatively.

Proton beam radiation for iris melanoma: case series and review of literature

Objective

Purpose of this study is to analyse the visual outcomes, the complication and eye retention rate as well as tumour control data of patients treated with proton beam radiation therapy (PBRT) for iris melanoma.

Methods

Retrospective case series and review based on patients’ records. All tumours were categorised according to the American Joint Committee of Cancer staging criteria for primary iris melanoma und underwent either sectorial or whole anterior segment PBRT.

Results

Thirteen cases were identified of which five received PBRT of the whole anterior segment and eight received sectorial PBRT. Local tumour control after a mean follow-up of 25 months was 92%. Complications after PBRT included cataract (46%), secondary glaucoma (31%), superficial keratitis (15%) and madarosis (8%). Complications were more common in patients necessitating irradiation of the entire anterior segment than in patients which received sectorial irradiation. Eye retention was achieved in all cases. No statistically significant difference in the mean best corrected visual acuity (BCVA) and intraocular pressure (IOP) was found before and after treatment. Comparison of mean BCVA and IOP between different treatment groups (complete anterior segment vs sectorial irradiation) at the last follow-up visit were also not significantly different. No patient developed metastatic disease during follow-up.

Conclusion

PBRT is a safe and vision preserving therapeutic modality for iris melanoma. Complete irradiation of the anterior segment is associated with higher complication rates.

Minimally Invasive Glaucoma Surgery-to Remove or Preserve the Trabecular Meshwork: That is the Question?

How to cite this article: Dada T, Mahalingam K, Bhartiya S. Minimally Invasive Glaucoma Surgery—to Remove or Preserve the Trabecular Meshwork: That is the Question? J Curr Glaucoma Pract 2021;15(2):47–51.

Comparison of subconjunctival microinvasive glaucoma surgery and trabeculectomy

PURPOSE

To assess surgical success and the post-operative development of intraocular pressure between XEN45^® gelstent, Preserflo^® MicroShunt and trabeculectomy with mitomycin C.

METHODS

Data from 105 eyes from 105 patients of matched cases with refractory open-angle glaucoma, who underwent surgery between January 2019, and August 2020, were evaluated. Patients underwent either stand-alone XEN gelstent insertion with Mitomycin C, stand-alone Preserflo with Mitomycin C or trabeculectomy with Mitomycin C. The primary outcome was the proportion of complete surgical success at 6 months post-operatively (i.e. intraocular pressure between 5mmHg and 18mmHg, no revision surgery, no loss of light perception and no post-operative pharmaceutical antiglaucomatous treatment). The reduction of intraocular pressure after 6 months, the classes of antiglaucomatous medication used post-operatively, best-corrected visual acuity, spherical refractive errors and astigmatism were assessed as secondary outcomes.

RESULTS

We included 35 eyes in each group. After 6-month follow-up, complete success was 73.5% [95%-CI: 57.9%-89.2%] in the trabeculectomy group, 51.4% [95%-CI: 34.0%-68.8%] in the XEN group and 74.2% [95%-CI: 57.9%-90.5%] in the Preserflo group (p = 0.08). Regarding secondary outcomes, the reduction of intraocular pressure was 12.1 ± 7.9 mmHg in the trabeculectomy group and was thereby 5.8 [95%-CI: 2.2-9.6] mmHg greater compared with the XEN group (p < 0.001) and 4.8 [95%-CI: 0.9-8.7] mmHg higher than the Preserflo group (p = 0.01).

CONCLUSIONS

No statistically significant differences were found between trabeculectomy, XEN45^® gelstent implantation and Preserflo^® MicroShunt implantation regarding surgical success after 6 months. Yet reduction in intraocular pressure was significantly higher in the trabeculectomy group. However, all three interventions resulted in sufficiently low post-operative intraocular pressure and may therefore be considered individually for glaucoma treatment.

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSION

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

Minimally Invasive Glaucoma Surgery: A Critical Appraisal of the Literature

Micro- or minimally invasive glaucoma surgeries (MIGS) have been the latest addition to the glaucoma surgical treatment paradigm. This term refers not to a single surgery, but rather to a group of distinct procedures and devices that aim to decrease intraocular pressure. Broadly, MIGS can be categorized into surgeries that increase the trabecular outflow [Trabectome, iStent (first and second generations), Hydrus microstent, Kahook Dual Blade and gonioscopy-assisted transluminal trabeculotomy], surgeries that increase suprachoroidal outflow (Cypass microstent and iStent Supra), and conjunctival bleb-forming procedures (Xen gel stent and InnFocus microshunt). Compared to traditional glaucoma surgeries, such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves), MIGS are touted to have less severe complications and shorter surgical time. MIGS represent an evolving field, and the efficacy and complications of each procedure should be considered independently, giving more importance to high-quality and longer-term studies.

Reoperation for complications within 90 days of minimally invasive glaucoma surgery

OBJECTIVE

To describe reoperations that occurred within 90 days of minimally invasive glaucoma surgery (MIGS) at a single institution over a 30-month period.

SETTING

Tertiary care hospital.

DESIGN

Retrospective case series.

METHODS

Charts of adult patients who underwent trabecular microbypass stents, gel microstents, and goniotomy procedures (including gonioscopy-assisted transluminal trabeculotomy) from October 1, 2017, to March 15, 2020, at Wills Eye Hospital were examined. Outcome measures were unanticipated reoperations within the first 90 days after MIGS procedures and the complications that led to these reoperations.

RESULTS

A total of 448 MIGS procedures were performed on 436 eyes of 348 patients over a 30-month period by 6 glaucoma surgeons. Of these, 206 (46.0%) were trabecular microbypass stents (198 iStent/iStent inject and 8 Hydrus), 152 (33.9%) were gel microstents, and 90 (20.1%) were goniotomy procedures. Combined phacoemulsification took place in 256 eyes (58.7%). Reoperation within 90 days took place in 23 (5.3%) of 436 eyes, including 16 (10.5%) of 152 eyes in the gel microstent group, 4 (2.0%) of 198 eyes in iStent/iStent inject group, and 3 (3.3%) of 90 eyes in the goniotomy group. Indications for reoperation were elevated intraocular pressure (IOP) in 16 (69.6%) of 23 eyes, gel microstent tip exposure with wound leakage in 3 (13.0%) of 23 eyes, and early gel microstent encapsulation without elevated IOP in 1 (4.3%) of 23 eyes. Two (8.7%) of 23 eyes required reoperation for intraocular lens complications, whereas 1 (4.3%) of 23 eyes had elevated IOP and aphakia requiring reoperation.

CONCLUSIONS

The rate of reoperation within the first 90 days after MIGS was low. Elevated IOP and complications associated with gel microstents were the main indications for reoperation.

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

Introduction

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

Methods

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

Results

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

Conclusion

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

Supplementary Information

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

Ethics of Glaucoma Widgets

How to cite this article: Dada T, Ramesh P, Sethi A, et al. Ethics of Glaucoma Widgets. J Curr Glaucoma Pract 2020;14(3):77–80.

Microinvasive Glaucoma Surgery: A Review of Schlemm's Canal-Based Procedures

Microinvasive glaucoma surgery has gained popularity over the past decade. It can be performed using three different mechanisms. In the present review, we focused on Schlemm’s canal (SC)-based surgery, which increases aqueous humor (AH) outflow into the aqueous veins by either removal of the trabecular meshwork (TM) or an increase in the tension in the TM. In primary open-angle glaucoma (POAG), the TM is the most likely region for increased AH outflow resistance. Theoretically, removal of the TM can improve the AH outflow; hence, glaucoma specialists focus on microsurgical dissection of the TM. In this review, we analyzed the available literature to examine SC-related microsurgical modalities based on the histopathological proofs of the localization of resistance of the AH outflow. First, we considered the role, anatomy, and physiology of the TM and SC. We referred to studies that describe the mechanisms and potential pathways, related to increased intraocular pressure in the POAG, that are targeted using the SC-related microsurgical interventions. Next, we took a closer look at the gonioscopic tools necessary for an ab-interno approach and explored incision canal surgery: ab-interno trabeculectomy using different instrumentation (Trabectome^®, Kahook Dual Blade) and variations of the technique. Thereafter, we discussed ab-interno canaloplasty, explaining the technique and reviewing its effectiveness. Finally, we presented the scope for future research in the field. Although the iStent also targets SC by bypassing it, this device has been reviewed extensively elsewhere.

Intraocular Pressure After Cataract Surgery Combined With Ab Interno Trabeculectomy Versus Trabecular Micro-bypass Stent: An Intrasubject Same-surgeon Comparison

PRECIS

Combining Trabectome or iStent with phacoemulsification equally reduces intraocular pressure (IOP) and IOP-lowering medication burden during a 24-month follow-up, with a possible advantage to the Trabectome in the early postoperative period.

PURPOSE

Intrasubject same-surgeon comparison between phacoemulsification combined with Trabectome (Phaco/Trabectome) versus one first-generation iStent (Phaco/iStent).

SETTINGS

Private glaucoma and cataract practice.

DESIGN

This is a retrospective interventional case series.

METHODS

Data collected at 3 to 4 and 20 to 24 hours and up to 30 months following Phaco/Trabectome in 1 eye and Phaco/iStent in the contralateral eye in patients with bilateral visually-significant cataract and open-angle glaucoma. Evaluations included IOP, intraocular pressure-lowering medications (IOPmeds), visual acuity, and complications.

RESULTS

Forty-five patients (90 eyes) were identified (age 76.5, 57 to 95 y). At 3 to 4 hours, IOP was above baseline in 12 and 13 eyes following Phaco/Trabectome and Phaco/iStent, respectively, but the degree of IOP elevation was smaller (P=0.048) following Phaco/Trabectome: 4.3 mm Hg, 2.0 to 6.6 mm Hg (95% confidence interval) versus Phaco/iStent: 8.7 mm Hg, 3.8 to 13.6 mm Hg. At 20 to 24 hours, compared with baseline, IOP was significantly lower after Phaco/Trabectome (P=0.004) but not after Phaco/iStent (P=0.14) although the rate of hyphema was higher following Phaco/Trabectome (12/45 vs. 2/45 eyes, P=0.007). IOP reduction from baseline at 3 to 4 hours was significantly larger (P=0.020) in the 21 eyes with hyphema: -3.9, -6.4 to -1.4 versus the 69 eyes without hyphema: -0.3, -2.0 to +1.4. At 1, 6, 12, and 24 months, IOP and number of IOPmeds were similar and significantly lower compared with baseline following either procedure. No complications were encountered in either group.

CONCLUSIONS

Combined phacoemulsification with either Trabectome or first-generation iStent similarly lowers IOP and IOPmeds burden at 1, 6, 12, and 24 months following surgery. The Trabectome may have an advantage in lowering IOP faster and lessening the degree of IOP elevations in the early postoperative period.

Outcomes and risk factors for failure after trabeculectomy in Taiwanese patients: medical chart reviews from 2006 to 2017

AIMS

To determine long-term outcomes and risk factors for failure after mitomycin C (MMC)-augmented initial trabeculectomy (IT) in Taiwanese patients.

METHODS

We reviewed medical records of patients with glaucoma undergoing IT during December 2006-December 2016. We defined complete success as an intraocular pressure (IOP) of >5 or ≤21 mm Hg or IOP reduction of ≥20% from baseline without supplemental medications and qualified success as the aforementioned IOP levels with or without supplemental medications. Kaplan-Meier survival and Cox proportional analyses evaluated success rates and risk factors for failure, respectively.

RESULTS

We enrolled 190 patients (237 eyes; mean age: 54.0±15.3 years; mean postoperative follow-up period: 68.4±35.1 months). Mean IOP and glaucoma medications decreased from 22.2±10.8 to 14.4±5.2 mm Hg (p<0.001) and 3.0±0.7 to 1.8±1.2 (p=0.015), respectively, at the last visit. Cumulative qualified success rates were 93.9%, 93.0%, 86.5% and 67.1% at the 1, 2, 5 and 10 years follow-up, respectively; however, only 7.7% of the eyes reached complete success at the last visit. Eyes with poor preoperative visual acuity were associated with low qualified success rates (HR=1.689, p=0.027); patients aged >70 years had higher complete success rates than did those aged ≤70 years. Five cases (2.11%) exhibited bleb-associated complications.

CONCLUSION

Despite satisfactory long-term success rates, most eyes needed medication for IOP control, supporting the notion of predisposed scarring vitality in patients of Chinese ethnicity following MMC-augmented trabeculectomy.

Effectiveness and limitations of minimally invasive glaucoma surgery targeting Schlemm's canal

Glaucoma surgery is performed to lower intraocular pressure (IOP); ideally, the IOP reduction is safely maintained for an extended period of time. Although trabeculectomy was considered the gold standard for glaucoma surgery for many years because of its effective IOP reduction, yet now it is considered unsafe because of serious complications. In recent years, minimally invasive glaucoma surgery (MIGS), which emphasizes safety and can be performed rapidly, has become widespread. Because MIGS does not involve conjunctival incisions, patients can undergo future trabeculectomy. If IOP reduction can be maintained safely, the number of anti-glaucoma drops can be reduced and visual function maintained, good outcomes for patients with glaucoma. Currently, many types of MIGS approved in Japan are reported to yield relatively good results, with targets of approximately 15-19 mmHg. However, the IOP-lowering effects of MIGS are limited. In procedures targeting Schlemm's canal, it is difficult to lower IOP beyond episcleral venous pressure. In some instances, a beneficial effect cannot be achieved if function is reduced beyond the collector channel. There are many unclear aspects regarding long-term outcomes following MIGS. Notably, investigation is ongoing to determine which patients are likely to benefit most from surgery. Based on previous reports, this review describes the characteristics and results of MIGS, approved in Japan, as well as underlying factors that affect the preoperative predictions and outcomes of the surgical procedure.

Retrospective evaluation of two-year results with a filtering trabeculotomy in comparison to conventional trabeculectomy by exact matching

Background: To compare two-year results of a filtering trabeculotomy (FTO) to conventional trabeculectomy (TE) in open-angle glaucoma by exact matching.

Methods: 110 patients received an FTO and 86 a TE. FTO avoided the need for an iridectomy due to a preserved trabeculo-descemet window anterior to the scleral flap. TE employed a trabecular block excision and iridectomy. Mitomycin C was used in both. FTO and TE were exact matched by baseline intraocular pressure (IOP) and the number of glaucoma medications. Complete and qualified success (IOP ≤18 mmHg and IOP reduction ≥ 30%, with or without medication) were primary endpoints. IOP, visual acuity (BCVA), complications and intervention were secondary endpoints.

Results: 44 FTO were exact matched to 44 TE. The IOP baseline in both groups was 22.5±4.7 mmHg on 3±0.9 medications. At 24 months, complete success was reached by 59% in FTO and 66% in TE, and qualified success by 59% in FTO and 71% in TE. In FTO, IOP was reduced to 12.4±4.3 mmHg at 12 months and 13.1±4.1 mmHg at 24 months. In TE, IOP was 11.3±2.2 mmHg at 12 months and 12.0±3.5 mmHg at 24 months. Medications could be reduced at 24 months to 0.6±1.3 in FTO and 0.2±0.5 in TE. There were no significant differences between the two groups in IOP, medications, complications or interventions at any point.

Conclusion: Modifying aqueous flow through a limited trabeculotomy in FTO yielded clinical outcomes similar to traditional TE but allowed to avoid an iridectomy.

Efficacy and safety of XEN®-Implantation vs. trabeculectomy: Data of a "real-world" setting

Objective

To compare surgical success, postoperative intraocular pressure and complication rates between trabeculectomy and XEN gelstent surgery in a cohort of glaucoma patients in a typical clinical setting.

Methods

A retrospective cohort study of consecutive patients with refractory open-angle glaucoma including patients who underwent either stand-alone XEN gelstent insertion with Mitomycin C or trabeculectomy with Mitomycin C between 2016 and 2018 at the University Eye Hospital Mainz, Germany. Primary outcome measure was the proportion of surgical success 1 year after surgery. Patients with an IOP ≤18mmHg, an intraocular pressure reduction of >20% and in no need of revision surgery or topical medication were considered a complete surgical success. If topical therapy was necessary, they were considered a qualified success. Multivariable logistic regression analysis was carried out for the primary outcome including gender, age, preoperative intraocular pressure and number of medication classes used preoperatively as adjustment variables.

Results

171 eyes of 144 patients were included, including 82 eyes of 58 patients in the XEN group and 89 eyes of 86 patients in the trabeculectomy group. The primary outcome defined as the proportion of surgical success after 1 year (mean 11.1 months ± 2.2) was similar for both groups. The complete success proportion was 65.5% (95%-CI: 55.6–75.9%) in the trabeculectomy group, and 58.5% (95%-CI: 47.6–69.4%) in the XEN group and not statistically different in our analysis model (crude OR = 0.61; 95%-CI: 0.31–1.22; adjusted OR = 0.66; 95%-CI: 0.32–1.37). The intraocular pressure reduction, as secondary outcome measure, was higher in the trabeculectomy group (10.5 mmHg) compared to the XEN group (7.2 mmHg; p = 0.003) at the 12-month follow-up.

Conclusion

Both XEN gelstent implantation and trabeculectomy show similar proportions of surgical success and of complications and are therefore both recommendable for clinical routine. However, trabeculectomy seems to be more effective in lowering intraocular pressure than the XEN implantation. A prospective randomized clinical trial is necessary to evaluate differences in the long-term clinical outcome.

Success of combined cataract extraction plus excimer laser trabeculotomy exceeds that of combined ab interno trabeculectomy with the trabectome or cataract extraction alone

PURPOSE

To determine the efficacy of cataract surgery alone and combined with two minimally invasive glaucoma surgery (MIGS) procedures (phaco-ELT and phaco-aiT).

METHODS

Data was collected from 12/2007 to 02/2012 in this retrospective, non-randomized, comparative single surgery center study. Reduction in IOP and hypotensive medication (AGD), change in visual acuity, success rates, and complications were computed by comparing preoperative data with data at 1 year postoperatively.

RESULTS

A total of 245 eyes of 245 subjects were included. Study eyes underwent phaco alone (38 eye) or combined phaco-ELT (105 eye) and phaco-aiT (102 eye). Phaco alone, combined phaco-ELT, and combined phaco-aiT lowered IOP by 1.5 ± 4.0 mmHg, 4.3 ± 5.6, and 5.3 ± 4.5 mmHg, respectively (P < 0.01). Survival time of phaco-ELT outreached survival time of phaco alone and combined phaco-aiT (20.6 ± 1.0 vs. 13.2 ± 0.4 and 12.9 ± 0.6 month, respectively). No serious complications or adverse events occurred. None of the cases required a subsequent procedure within the first year to lower IOP further.

CONCLUSIONS

All three surgical procedures lowered IOP and reduced medication. However, the IOP-lowering efficacy of the two combined MIGS procedures exceeded the effect of phaco alone. A combined phaco and MIGS procedures seem reasonable to consider whenever a cataract surgery in an eye with glaucoma or ocular hypertension is considered. In addition, the combined MIGS procedure effectively lowers IOP whenever a target IOP in the mid-teens is sufficient. In this study, the nonthermal phaco-ELT procedure showed superior efficacy at 1 year over phaco alone and phaco-aiT in the Kaplan-Meier statistics.

Similar Performance of Trabectome and Ahmed Glaucoma Devices in a Propensity Score-matched Comparison

PURPOSE

To apply propensity score matching to Ahmed glaucoma drainage implants (AGI) to trabectome-mediated ab interno trabeculectomy (AIT). Recent data suggest that AIT can produce results similar to AGI traditionally reserved for more severe glaucoma.

METHODS

AGI and AIT patients with at least 1 year of follow-up were included. The primary outcome measures were intraocular pressure (IOP), glaucoma medications, and a Glaucoma Index (GI) score. GI reflected glaucoma severity based on visual field, the number of preoperative medications, and preoperative IOP. Score matching used a genetic algorithm consisting of age, sex, type of glaucoma, concurrent phacoemulsification, baseline number of medications, and baseline IOP. Patients without a close match were excluded.

RESULTS

Of 152 patients, 34 AIT patients were matched to 32 AGI patients. Baseline characteristics including ethnicity, IOP, the number of medications, glaucoma type, the degree of visual field loss and GI were not significantly different between AIT and AGI. AIT had a preoperative IOP of 23.6±8.1 mm Hg compared with 26.5+10.6 mm Hg for AGI. At 12 months, the mean IOP was 15.0±9 mm Hg for AIT versus 15.0±4 mm Hg for AGI (P=0.8), whereas the number of drops was 2.3±2.2 for AIT versus 3.6±1.3 for AGI (P=0.016). Only 6 AIT patients (17.6%) required further surgery within the first 12 months versus 9 (28%) for AGI. Success, defined as IOP<21 mm Hg, <20% reduction and no reoperation, was achieved in 76% of AIT versus 69% of AGI (P=0.48). Complications occurred in 13% of AGI and 0.8% of AIT.

CONCLUSIONS

A propensity score-matched comparison of AIT and AGI showed an equivalent IOP reduction through 1 year. Surprisingly, the AGI group required more glaucoma medications than the AIT group at 6 and 12 months.

Effect of combined goniotomy and phacoemulsification on intraocular pressure in open-angle glaucoma patients

IMPORTANCE

Although goniotomy is known to be successful in treating congenital glaucoma, its effect in adult glaucoma patients remains unclear.

BACKGROUND

To evaluate the efficacy and safety of goniotomy performed simultaneously with cataract surgery in treatment of open-angle glaucoma (OAG).

DESIGN

Retrospective comparative study.

PARTICIPANTS

A total of 76 patients with moderately controlled OAG (intraocular pressure [IOP] ≤ 21 mmHg using medications) undergoing cataract surgery.

METHODS

Comparison of patients who underwent the conventional goniotomy during cataract surgery (combined goniotomy group) with those who underwent cataract surgery alone (phaco group).

MAIN OUTCOME MEASURES

Changes in IOP and medications, and complications through 12 months.

RESULTS

Baseline IOP was 18.2 ± 2.4 mmHg in the combined goniotomy group and 17.4 ± 1.9 mmHg in the phaco group; number of medications was 2.6 ± 1.1 and 2.4 ± 0.9, respectively (P > 0.05). The reduction in IOP and medication use from baseline in the combined goniotomy group was significantly greater at 12 months compared to the phaco group (-3.1 ± 2.9 mmHg vs -1.3 ± 2.4 mmHg and -1.2 ± 0.9 vs -0.7 ± 0.9, respectively, both P < 0.05). The success rate was 76.7% in the combined goniotomy group and 50.0% in the phaco group at 12 months (P = 0.021). No significant complication was observed in either group.

CONCLUSIONS AND RELEVANCE

Combined goniotomy and cataract surgery showed a significantly greater reduction in IOP and number of medications compared to cataract surgery alone at 1 year after surgery, with similarly favourable safety profiles.

Ab interno trabeculectomy with Trabectome: outcomes in African American versus Caucasian patients

OBJECTIVE

To compare the intraocular pressure-lowering efficacy and complication rate of ab interno trabeculectomy with the Trabectome between African American (AA) and Caucasian patients with open-angle glaucoma.

METHODS

A total of 164 patients (82 AA and 82 Caucasian) who underwent ab interno trabeculectomy over an 8-year period were included in this prospective, case-control study. The Neomedix database was used to look for AA or Caucasian patients with open-angle glaucoma who underwent Trabectome with or without phacoemulsification.

RESULTS

The average IOP of AA patients was reduced from 21.2 ± 6.8 mm Hg to 16.1 ± 4.1 mm Hg at 12 M (p < 0.01), and the mean number of glaucoma medications was reduced from 2.4 ± 1.3 to 2.0 ± 1.4 (p = 0.13). Among Caucasians, the mean IOP was reduced from 21.2 ± 6.8 mm Hg to 15.7 ± 4.2 mm Hg at 12 M (p < 0.01), and the number of medications dropped from 2.4 ± 1.2 to 1.7 ± 1.3 (p < 0.01). No statistically significant difference was found between these 2 race groups in IOP, number of medications, and complications. For complications with Trabectome alone, 13% of AA and 9% of Caucasian patients needed secondary surgery. There was only 1 case of hypotony which was in the AA group. For complications with Trabectome combined with phacoemulsification, 4% of AA as well as 4% of Caucasian patients required secondary surgery. There was only 1 case of hypotony which was in the Caucasian group.

CONCLUSION

Ab interno trabeculectomy with Trabectome is associated with a reduction in IOP in both race groups with a similar complication and survival profiles.

Prospective randomized controlled trial of phaco-trabectome versus phaco-trabeculectomy in patients with open angle glaucoma

OBJECTIVE

To compare the efficacy and safety of ab interno trabeculectomy with the Trabectome combined with cataract surgery (phaco-AIT) versus Trabeculectomy with mitomycin C combined with cataract surgery (phaco-Trab) in open-angle glaucoma.

METHODS

A prospective randomized controlled trial with a single surgeon and surgical center was undertaken. Patients were recruited from July 2009 to October 2014. Primary outcomes were mean intraocular pressure (IOP) at 6 months and surgical complications. Secondary outcomes were mean IOP at 12 months, achievement of target IOP, number of glaucoma medications, and rate of secondary surgery.

RESULTS

The trial was ended early before achieving our intended sample size due to difficulties in recruitment and lack of clinical equipoise over time. Nineteen patients were enrolled, 10 phaco-AIT and 9 phaco-Trab. Baseline IOP was 20.0 ± 5.3 in phaco-AIT and 23.1 ± 6.4 mm Hg in phaco-Trab (p = 0.22). IOP decreased to 17.5 ± 3.8 and 16.0 ± 6.0 mm Hg at 6 months (p = 0.54), and 16.8 ± 2.7 and 17.1 ± 5.0 mm Hg at 1 year (p = 0.57), respectively. Mean number of glaucoma medications at baseline was 1.8 ± 1.3 in phaco-AIT and 1.4 ± 1.1 in phaco-Trab (p = 0.59). Mean number of glaucoma medications decreased to 0.78 ± 1.39 and 0.38 ± 0.74 at 6 months (p = 0.68), and 0.44 ± 0.88 and 0.75 ± 0.89 at 1 year (p = 0.41), respectively. Mild and moderate complications were seen in both treatment groups, but severe complications were seen only in phaco-Trab. One secondary glaucoma procedure was required in the phaco-AIT group.

CONCLUSIONS

Phaco-AIT achieved similar IOP lowering at 6 and 12 months compared with phaco-Trab with a similar number of glaucoma medications required at 1 year, and no serious complications were identified in the Phaco-AIT group.

Comparative outcomes of trabeculotomy ab externo versus trabecular ablation ab interno for open angle glaucoma

PURPOSE

To compare clinical outcomes between trabeculotomy ab externo (TLO) and trabecular ablation ab interno using a Trabectome (TAT) for open angle glaucoma (OAG).

STUDY DESIGN

Prospective and retrospective cohort study.

METHODS

We prospectively recruited 68 patients who underwent TAT between May 2013 and July 2015, and retrospectively recruited 59 patients who underwent TLO between April 2010 and May 2013. We included OAG patients who could be followed up for more than 12 months after surgery. Surgical outcomes were compared between groups. Kaplan-Meier analyses and Cox proportional hazards' models were used for four sets of criteria using postoperative intraocular pressures (IOP) ≤ 18 or ≤ 16 mmHg, and/or showing ≥ 20% reduction from baseline.

RESULTS

Mean preoperative IOPs were 22.6 ± 7.4 mmHg in the TAT group and 24.3 ± 6.6 mmHg in the TLO group. Mean postoperative IOPs in the TAT group were 15.8 ± 3.6 mmHg at 12-months, and 15.7 ± 5.5 mmHg at 36-months, and 16.0 ± 3.4 mmHg at 12 months and 15.2 ± 3.8 mmHg at 36 months in the TLO group. Postoperatively, success rates at 36-months were significantly higher in the TLO group in some criteria; IOP reductions at 1- and 2- years were significantly higher in the TLO group; these differences were not significant after adjustment with other potential prognostic factors. The number of glaucoma medications were significantly higher in the TAT group, at 2-years (P < 0.001) but not at 3-years (P = 0.22).

CONCLUSION

Surgical successes following TLO and TAT are not significantly different 3 years postoperatively after adjustment of potential prognostic factors.

Inadvertent Cyclodialysis Cleft and Hypotony Following Ab-Interno Trabeculotomy Using the Trabectome Device Requiring Surgical Repair

PURPOSE

To report the first case of inadvertent cyclodialysis cleft and hypotony requiring surgical repair following ab-interno trabeculotomy (AIT) using the Trabectome device, and the postoperative clinical results following direct suture cyclopexy.

METHODS

A 55-year-old man with hypotonous maculopathy secondary to cyclodialysis cleft inadvertently created 3 years earlier during AIT using the Trabectome device was referred for repair. Direct suture cyclopexy was performed and topical homatropine and dexamethasone drops were prescribed postoperatively.

RESULTS

Gonioscopic examination revealed complete cleft closure on postoperative day 1 confirmed by anterior segment optical coherence tomography. At 11 weeks postoperatively, visual acuity had improved from 20/400 to 20/40, with resolution of preoperative macular folds on fundoscopic examination. At 9 months postoperatively, visual acuity had further improved to 20/20 with intraocular pressure stable at 9 mm Hg maintained on travoprost and brimonidine.

CONCLUSIONS

Inadvertent cyclodialysis cleft from a malpositioned AIT and resultant hypotony is rare and in this case was successfully treated by direct suture cyclopexy.

Co-management of cataract and glaucoma in the era of minimally invasive glaucoma surgery

PURPOSE OF REVIEW

This review discusses the options available to be used in conjunction with phacoemulsification cataract surgery to control intraocular pressure. We present a strategy for planning which surgery should be performed based on goals of care.

RECENT FINDINGS

New clinical evidence for using the CyPass, Kahook and Xen45 devices has been published recently and is summarized.

SUMMARY

Cataract and glaucoma frequently exist together. Because the field of glaucoma surgical care is expanding and cataract surgery is becoming progressively safer, it is important to frequently re-evaluate our treatment paradigms. We review and evaluate current studies and treatment options.

Microinvasive Glaucoma Surgery: An Evidence-Based Assessment

Introduction

The advent of Microinvasive Glaucoma Surgery (MIGS) offers a novel approach in the treatment of glaucoma with the number of procedures developing at an exciting pace.

Areas Covered

MIGS procedures aim to lower intraocular pressure (IOP) via four mechanisms: (1) increasing trabecular outflow, (2) increasing outflow via suprachoroidal shunts, (3) reducing aqueous production, and (4) subconjunctival filtration. A comprehensive search for published studies for each Microinvasive Glaucoma Surgery (MIGS) device or procedure was undertaken using the electronic database PubMed. Search terms included 'minimally invasive glaucoma surgery', 'microincisional glaucoma surgery', and 'microinvasive glaucoma surgery'. A manual search for each device or procedure was also performed. After review, randomized control trials and prospective studies were preferentially included.

Expert Opinion

These procedures offer several benefits: an improved safety profile allowing for intervention in earlier stages of glaucoma, combination with cataract surgery, and decreased dependence on patient compliance with topical agents. Established MIGS procedures have proven efficacy and more recent devices and procedures show promising results. Despite this, further study is needed to assess the long term IOP-lowering effectiveness of these procedures. Particularly, rigorous study with more randomized control trials and head-to-head comparisons would allow for better informed clinical and surgical decision-making. MIGS offers new solutions for glaucoma treatment.

Efficacy, Safety, and Risk Factors for Failure of Standalone Ab Interno Gelatin Microstent Implantation versus Standalone Trabeculectomy

PURPOSE

To compare the efficacy, safety, and risk factors for failure of standalone ab interno gelatin microstent implantation with mitomycin C (MMC) versus trabeculectomy with MMC.

DESIGN

International, multicenter, retrospective interventional cohort study.

PARTICIPANTS

Three hundred fifty-four eyes of 293 patients (185 microstent and 169 trabeculectomy) with no prior incisional surgery.

METHODS

Consecutive eyes with uncontrolled glaucoma underwent microstent or trabeculectomy surgery from January 1, 2011 through July 31, 2015 at 4 academic ophthalmology centers: Toronto, Canada; Frankfurt, Germany; Salzburg, Austria; and Leuven, Belgium.

MAIN OUTCOME MEASURES

Primary outcome measure was hazard ratio (HR) of failure, with failure defined as 2 consecutive intraocular pressure (IOP) readings of <6 mmHg with vision loss or >17 mmHg without glaucoma medications (complete success) at least 1 month after surgery despite in-clinic interventions (including needling). Secondary outcome measures included IOP thresholds of 6 to 14 mmHg and 6 to 21 mmHg and same thresholds allowing for medications (qualified success), interventions, complications, and reoperations.

RESULTS

Baseline characteristics were similar, except more men (56% vs. 43%), younger patients (average, by 3 years), better preoperative visual acuity (22% vs. 32% with 0.4 logarithm of the minimum angle of resolution vision or worse), and more trabeculoplasty (52% vs. 30%) among microstent eyes. The adjusted HR of failure of the microstent relative to trabeculectomy was 1.2 (95% confidence interval [CI], 0.7-2.0) for complete success and 1.3 (95% CI, 0.6-2.8) for qualified success, and similar for other outcomes. Time to 25% failure was 11.2 months (95% CI, 6.9-16.1 months) and 10.6 months (95% CI, 6.8-16.2 months) for complete success and 30.3 months (95% CI, 19.0-∞ months) and 33.3 months (95% CI, 25.7-46.2 months) for qualified success. Overall, white ethnicity was associated with decreased risk of failure (adjusted HR, 0.49; 95% CI, 0.25-0.96), and diabetes was associated with increased risk of failure (adjusted HR, 4.21; 95% CI, 2.10-8.45). There were 117 and 165 distinct interventions: 43% and 31% underwent needling, respectively, and 50% of trabeculectomy eyes underwent laser suture lysis. There were 22 and 30 distinct complications, although most were transient. Ten percent and 5% underwent reoperation (P = 0.11).

CONCLUSIONS

There was no detectable difference in risk of failure and safety profiles between standalone ab interno microstent with MMC and trabeculectomy with MMC.

Outcome of primary trabeculotomy ab interno (Trabectome) surgery in patients with steroid-induced glaucoma

To determine the efficacy and safety of Trabectome surgery on patients with steroid response, ranging from ocular hypertension refractory to maximal medical therapy to the development of steroid-induced glaucoma.A nonrandomized, nonblinded, retrospective study of 20 subjects with steroid response was conducted. All 20 eyes underwent Trabectome surgery alone. Nine subjects had steroid response with unremarkable visual field, 3 had mild steroid-induced glaucoma, and 8 had advanced steroid-induced glaucoma. Outcome measures included intraocular pressure (IOP), number of glaucoma medications, need for secondary glaucoma surgery, and steroid regimen. Mann-Whitney U test was used to compare postoperative IOP and number of medications to preoperative IOP and number of medications. Kaplan-Meier was used for survival analysis, and success was defined as: IOP reduced by 20% or more on any 2 consecutive visits after 3 months; IOP ≤21 mm Hg on any 2 consecutive visits after 3 months; and no secondary glaucoma surgery.The average preoperative IOP was 33.8 ± 6.9 mm Hg and average preoperative glaucoma medication usage was 3.85 ± 0.75 medications. At 12 months, the IOP was reduced to 15.00 ± 3.46 mm Hg (P = 0.03) and glaucoma medication was reduced to 2.3 ± 1.4 (P < 0.01). The survival rate at 12 months was 93%. At 12 months, 10 patients were continued on their preoperative steroid treatments, 5 were on tapered steroid treatments, and 5 had ceased steroid treatments entirely. One patient required secondary glaucoma surgery (glaucoma drainage device). No other complications were noted.The Trabectome procedure is safe and highly effective for steroid-response glaucoma, even in the context of continued steroid treatment.

Modified goniotomy as an alternative to trabectome in primary open angle glaucoma and pseudoexfoliation glaucoma: 1 year results

OBJECTIVE

To assess the outcome of modified goniotomy and trabeculotomy ab interno (Trabectome) surgery in adult primary open-angle glaucoma (POAG) and pseudoexfoliation (PEX) glaucoma.

DESIGN

Retrospective cohort outcome study.

PARTICIPANTS

Two hundred and thirty-six eyes of 236 patients.

METHODS

This cohort outcome study included 68 POAG (mean age: 65.7 ± 16.0 years) and 22 PEX glaucoma patients (mean age: 78.3 ± 7.9 years) in the modified goniotomy cohort and 119 POAG (mean age: 73.9 ± 9.6 years) and 27 PEX glaucoma patients (mean age: 75.2 ± 8.0 years) in the Trabectome cohort. Modified goniotomy is defined as combined ab interno cyclodialysis and goniotomy. The patients were followed up for 12 months, and we analysed the data using SPSS v19.0.

RESULTS

In POAG, the intraocular pressure (IOP) was significantly reduced by 4.6 mm Hg in the Trabectome cohort (p < 0.001) and by 5.8 mm Hg (p < 0.001) in the goniotomy group at 1-year follow-up. In PEX glaucoma, the mean IOP was reduced by 9.7 mm Hg (p = 0.002) in the Trabectome surgery and by 6.7 mm Hg (p = 0.004) in the goniotomy cohort 1 year later. Comparing both surgery techniques in POAG, no significant correlation was found in terms of IOP at any of the follow-up visits (IOP at 1 year, p = 0.553). In PEX glaucoma, the IOP, visual acuity, and number of glaucoma medications did not differ significantly between the 2 surgery techniques 1 year later (IOP: p = 0.300; VA: p = 0.391; therapy: p = 0.908).

CONCLUSION

Modified goniotomy and Trabectome surgery are reliable and effective tools for the management of moderate POAG and PEX glaucoma. There was no significant difference in IOP between the 2 procedures over a follow-up period of 1 year.

Is there a change in the quality of life comparing the micro-invasive glaucoma surgery (MIGS) and the filtration technique trabeculectomy in glaucoma patients?

PURPOSE

This study was conducted to assess the impact on the Quality of Life (QOL) of micro-invasive glaucoma surgery (MIGS: iStent, Trabectome) and a penetrating technique such as Trabeculectomy (TE).

METHODS

This study evaluated 88 eyes of 88 open angle glaucoma patients undergoing glaucoma surgery: 43 (mean age 72.8 ± 8.8y, female 59.5 %, male 40.5 %) Trabectome (NeoMedix, Inc., Tustin, CA, USA), 20 (mean age 68.6 ± 16.4y, female 60 %, male 40 %) iStent (Glaucos Corporation, Laguna Hills, CA, USA), and 25 TE patients (mean age 74.2 ± 9.1y female 58.3 %, male 41.7 %). The National Eye Institute-Visual Functioning Questionnaire (VFQ-25) survey was used to assess the QOL at 6 months post surgery. The following 12 QOL parameters were evaluated: general health, ocular pain, general vision, near and distance activities, mental health, social functioning, role difficulties, dependency, driving, color vision, and peripheral vision. Intraocular pressure (IOP), number of topical medications, and visual acuity (VA) were examined preoperatively, 1 day, 6 weeks, 3 months, and 6 months post surgery. Statistical data were calculated using SPSS (v20.0, SPSS, Inc.).

RESULTS

There was no significant difference between TE and MIGS in the quality of life 6 months postoperatively. IOP was significantly lower in TE compared to MIGS at 6 weeks and 3 months postoperatively (p = 0.046 and p = 0.046). Number of medications was significantly decreased in TE compared to MIGS (p < 0.001). A significant difference in VA between TE and MIGS could be assessed at day 1 post-op (p = 0.011).

CONCLUSION

In this study cohort, the QOL can be maintained by all three surgical techniques. Patients, however, need lower numbers of topical medication in TE, which would impact QOL even though it is not included in the NEI-VFQ-25. The decision of the most appropriate surgical technique should be made by including single QOL categories, IOP and glaucoma medication outcome.

Differential Canalograms Detect Outflow Changes from Trabecular Micro-Bypass Stents and Ab Interno Trabeculectomy

Recently introduced microincisional glaucoma surgeries that enhance conventional outflow offer a favorable risk profile over traditional surgeries, but can be unpredictable. Two paramount challenges are the lack of an adequate training model for angle surgeries and the absence of an intraoperative quantification of surgical success. To address both, we developed an ex vivo training system and a differential, quantitative canalography method that uses slope-adjusted fluorescence intensities of two different chromophores to avoid quenching. We assessed outflow enhancement by trabecular micro-bypass (TMB) implantation or by ab interno trabeculectomy (AIT). In this porcine model, TMB resulted in an insignificant (p > 0.05) outflow increase of 13 ± 5%, 14 ± 8%, 9 ± 3%, and 24 ± 9% in the inferonasal, superonasal, superotemporal, and inferotemporal quadrant, respectively. AIT caused a 100 ± 50% (p = 0.002), 75 ± 28% (p = 0.002), 19 ± 8%, and 40 ± 21% increase in those quadrants. The direct gonioscopy and tactile feedback provided a surgical experience that was very similar to that in human patients. Despite the more narrow and discontinuous circumferential drainage elements in the pig with potential for underperformance or partial stent obstruction, unequivocal patterns of focal outflow enhancement by TMB were seen in this training model. AIT achieved extensive access to outflow pathways beyond the surgical site itself.

Ab interno trabeculectomy: patient selection and perspectives

Ab interno trabeculectomy is one among several recently introduced minimally invasive glaucoma surgeries that avoid a conjunctival incision and full-thickness sclerostomy involved in traditional glaucoma surgery. Ablation of the trabecular meshwork and inner wall of Schlemm's canal is performed in an arcuate fashion via a clear corneal incision, alone or in combination with phacoemulsification cataract surgery. Intraocular pressure reduction following ab interno trabeculectomy is limited by resistance in distal outflow pathways and generally stabilizes in the mid-to-high teens. Relief of medication burden has been demonstrated by some studies. A very low rate of complications, most commonly transient hyphema and intraocular pressure elevations in the immediate postoperative period, have been reported. However, available data are derived from small retrospective and prospective case series. Randomized, controlled trials are needed to better elucidate the potential merits of ab interno trabeculectomy in the combined setting versus phacoemulsification cataract surgery alone and to compare it with other minimally invasive glaucoma surgeries.

Intraocular pressure 3 to 4 hours and 20 hours after cataract surgery with and without ab interno trabeculectomy

PURPOSE

To evaluate intraocular pressure (IOP) immediately after cataract surgery with or without ab interno trabeculectomy (Trabectome) and whether trabeculectomy-related hyphema increases the risk for IOP spikes.

SETTINGS

Private glaucoma practice.

DESIGN

Retrospective interventional nonrandomized comparative chart review.

METHODS

Intraocular pressure was measured 3 to 4 hours and 20 hours postoperatively.

RESULTS

The combined group comprised 73 eyes of 73 patients and the cataract-only group, 75 eyes of 75 patients. The mean preoperative IOP was 15.8 mm Hg ± 3.6 (SD) and 14.9 ± 3.0 mm Hg, respectively (P = .09). In the combined group, the IOP decrease was significant at 3 to 4 hours (P = .0003) and 20 hours (P = .0007). In the cataract-only group, the IOP increased significantly (P < .0001 and P = .0035, respectively). The mean IOP was significantly lower in the combined group than in the cataract-only group at 3 to 4 hours (12.8 ± 5.9 mm Hg versus 19.7 ± 7.5 mm Hg) and 20 hours (12.7 ± 7.0 mm Hg versus 17.2 ± 5.9 mm Hg) (both P < .0001). Significantly fewer eyes in the combined group than in the cataract-only group had IOP spikes (overall, P = .0077; 3 to 4 hours, P = .001). Hyphema occurred in 35 eyes (47.9%) in the combined group; however, the IOP was similar with or without hyphema. Only 1 eye with an IOP spike in the combined group had hyphema.

CONCLUSION

Combining ab interno trabeculectomy and cataract surgery reduced short-term postoperative IOP and the incidence of IOP spikes despite the common hyphema.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Combined phacoemulsification and trabectome for treatment of glaucoma

Ab interno trabeculectomy with the trabectome is a microincisional glaucoma surgery modality with an electrosurgical device to ablate the trabecular meshwork and inner wall of Schlemm canal to restore conventional outflow along its physiological route, thereby decreasing intraocular pressure. The device was approved by the FDA in 2004 and has since gained widespread use. Trabectome can be performed on its own or combined with cataract surgery for the treatment of ocular hypertension or advanced glaucoma with similar intraocular pressure reduction. It can be used after failed classical glaucoma surgeries and in narrow angles. Postoperative average intraocular pressure is independent of preoperative pressure and can be expected to be near 15 mm Hg with a theoretical minimum close to episcleral venous pressure. In combination with tube shunts, low intraocular pressures can be achieved during the hypertensive phase and long term. Although early postoperative hyphema is common, complications are rare and similar to those seen in cataract surgery, resulting in a safety profile that is favorable compared to older glaucoma surgeries. Aqueous angiography that is under development will allow anatomically targeted ablation.