Outcomes of ab interno trabeculectomy with the trabectome after failed trabeculectomy

Outcomes of Gonioscopy-Assisted Transluminal Trabeculotomy in Eyes With Prior Failed Glaucoma Surgery

PRCIS

This study concludes that GATT can be an effective and safe surgical alternative for managing IOP in eyes with prior failed glaucoma surgeries, associated with minimal complications.

PURPOSE

To report outcomes of gonioscopy-assisted transluminal trabeculotomy (GATT) in eyes with prior failed glaucoma surgery.

PATIENTS AND METHODS

A retrospective study involving 30 eyes of 30 patients, all of whom had open angles on gonioscopy, experienced prior glaucoma surgery failures, and subsequently underwent GATT. The primary outcome measure was success defined as complete when the intraocular pressure (IOP) was >5 and ≤21/16 mm Hg without glaucoma medications and qualified with medications.

RESULTS

The mean age was 51.8±16.1 years. Twenty-one eyes underwent GATT and 9 eyes underwent phaco-GATT. Twenty-seven eyes had failed trabeculectomy and 3 eyes had failed glaucoma drainage device. Post-GATT, the IOP decreased from 27.1±7 to 16.9±6 mm Hg (P<0.001) at the end of 15 months, with a mean drop in AGM from 4.9±1.0 to 2±1.6. At postoperative 1 year, the probability of complete success was 20% (95% CI: 9-43) for an IOP criterion of both 21 and 16 mm Hg. The qualified success probability at 1 year was 82% (67-100) for an IOP criterion of 21 mm Hg and 57% (38-84) for an IOP criterion of 16 mm Hg. Risk factor for failure was older age [hazard ratio (HR): 1.03, 95% CI: 1.01-1.06]. The complications noted were hyphema in 14 eyes (46%), majority resolved within 1 week and all by 2 weeks. None needed any intervention.

CONCLUSIONS

This study concludes that GATT can be an effective and safe surgical alternative for managing IOP in eyes with prior failed glaucoma surgeries, associated with minimal complications.

VEGF-A-induced changes in distal outflow tract structure and function

PURPOSE

To investigate changes in distal outflow tract vessels caused by VEGF-A and their impact on outflow.

METHODS

We compared VEGF-A perfused porcine anterior segments with and without trabecular meshwork (TM) to control eyes. In the first experiment (n=48), we analyzed live changes of the outflow tract with spectral-domain optical coherence tomography (SD-OCT) over 3 h and reconstructed them in 3D. In a second experiment (n=32), we measured the intraocular pressure (IOP) variation in response to VEGF-A over 48 h and computed the outflow facility.

RESULTS

VEGF-A increased the vessel volume of the distal outflow tract by 16.8±10.6% while control eyes remained unchanged (0.5±6.8%). Volume changes occurred within the first 100 min before plateauing at 140 min. VEGF-A enhanced the outflow facility in eyes without TM by 38.6±25.5% at 24 h as compared to controls (p<0.05).

CONCLUSION

VEGF-A dilated vessels of the distal outflow tract and increased the outflow facility even after TM removal, pointing to a regulatory mechanism independent of proximal structures.

Efficacy of Endotrabeculectomy (Trabecula Ablation Ab Interno with the Forceps) for Open-angle Glaucoma

Aim

To investigate the efficacy of endotrabeculectomy (ETE) performed either alone or combined with phacoemulsification (phaco) in patients with primary open-angle glaucoma (POAG).

Materials and methods

Investigations were done in two groups. The first group (38 patients, 38 eyes) with POAG underwent ETE, and the second group of 126 patients (126 eyes) with POAG and cataracts underwent ETE and phaco. The hypotensive effect of the surgery was evaluated.

Results

In the ETE group, the mean intraocular pressure (IOP) was reduced from 20.25 ± 3.30 to 14.94 ± 1.95 mm Hg (26.2% reduction, p < 0.001) at 12 months. The number of medications was reduced from 2.8 ± 1.0 to 1.5 ± 1.0 (p < 0.001) at 12 months after the surgery. In the phaco-ETE group, the mean IOP was reduced from 18.24 ± 3.20 to 14.83 ± 1.71 mm Hg (18.7% reduction, p < 0.001) at 12 months. The mean number of medications was reduced from 2.2 ± 1.1 to 1.0 ± 1.0 (p < 0.001) at 12 months after the surgery. The success rate defined as a final IOP of <16 mm Hg using the Kaplan-Meier curve at 12 months was 73.8%. There were no complications that led to a constant visual decrease.

Clinical significance

Our study shows that ETE is technically simple, gives the ability to remove trabecula in any quadrant, and effectively reduces IOP in patients with POAG.

Conclusion

Endotrabeculectomy (ETE) is a safe and relatively simple procedure that significantly reduces IOP. The minimally invasive nature of the ETE allows expanding indications for combined treatment of glaucoma and cataract.

How to cite this article

Novytskyy IY, Novytskyy MI. Efficacy of Endotrabeculectomy (Trabecula Ablation Ab Interno with the Forceps) for Open-angle Glaucoma. J Curr Glaucoma Pract 2023;17(1):15-21.

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.

Valve-Like Outflow System Behavior With Motion Slowing in Glaucoma Eyes: Findings Using a Minimally Invasive Glaucoma Surgery–MIGS-Like Platform and Optical Coherence Tomography Imaging

Purpose

This study aimed to investigate anatomic relationships and biomechanics of pressure-dependent trabecular meshwork and distal valve-like structure deformation in normal and glaucoma eyes using high-resolution optical coherence tomography (HR-OCT).

Methods

We controlled Schlemm’s canal (SC) pressure during imaging with HR-OCT in segments of three normal (NL) and five glaucomatous (GL) ex vivo eyes. The dissected limbal wedges were studied from 15 locations (5 NL and 10 GL). A minimally invasive glaucoma surgery (MIGS)-like cannula was inserted into the SC lumen, whereas the other end was attached to a switch between two reservoirs, one at 0, the other at 30 mm Hg. A steady-state pressure of 30 mm Hg was maintained to dilate SC and collector channels (CC) during 3D volume imaging. The resulting 3D lumen surface relationships were correlated with internal structural features using an image mask that excluded tissues surrounding SC and CC. While imaging with HR-OCT, real-time motion responses in SC and CC areas were captured by switching pressure from 0 to 30 or 30 to 0 mm Hg. NL vs. GL motion differences were compared.

Results

Lumen surface and internal relationships were successfully imaged. We identified SC inlet and outlet valve-like structures. In NL and GL, the mean SC areas measured at the steady-state of 0 and 30 mm Hg were each significantly different (p &lt; 0.0001). Synchronous changes in SC and CC lumen areas occurred in &lt;200 ms. Measured SC area differences at the steady-state 0 and 30 mmHg, respectively, were larger in NL than GL eyes (p &lt; 0.0001). The SC motion curves rose significantly more slowly in GL than NL (p &lt; 0.001). Pressure waves traveled from the cannula end along the SC lumen to CC and deep intrascleral channels.

Conclusion

HR-OCT provided simultaneous measurements of outflow pathway lumen surfaces, internal structures, and biomechanics of real-time pressure-dependent dimension changes. We identified SC inlet and outlet valve-like structures. GL tissues underwent less motion and responded more slowly than NL, consistent with increased tissue stiffness. A MIGS-like shunt to SC permitted pulse waves to travel distally along SC lumen and into CC.

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.

Microinvasive Glaucoma Surgery: An Evidence-Based Review

PURPOSE

Interest in micro-invasive glaucoma surgery (MIGS) has exploded over the last 8 years with an increase in MIGS procedures of at least 400% in the United States, according to Medicare data. MIGS is an umbrella term that can cover many different types of surgeries. This review focuses on peer-reviewed evidence for Trabectome^®, iStent inject^®, Kahook Dual Blade^®, XEN^® Gel Stent, and Hydrus^®.

METHODS

We present key recent studies evaluating the efficacy and safety of MIGS in various types of glaucoma patients with different stages of disease.

CONCLUSION

We conclude that MIGS is generally safe and efficacious, although only some MIGS have been studied through randomized clinical trials. When comparing and contrasting the different MIGS procedures, large prospective studies are not yet the norm. High-quality large prospective studies involving MIGS will be an important next step as ophthalmologists decide how to incorporate MIGS into their surgical armamentarium.

Exact matching of trabectome-mediated ab interno trabeculectomy to conventional trabeculectomy with mitomycin C followed for 2 years

PURPOSE

We used exact matching for a highly balanced comparison of ab interno trabeculectomy (AIT) with the trabectome to trabeculectomy with mitomycin C (TRAB).

METHODS

A total of 5485 patients who underwent AIT were exact-matched to 196 TRAB patients by baseline intraocular pressure (IOP), number of glaucoma medications, and glaucoma type. Nearest-neighbor-matching was applied to age. Success was defined as a final IOP of less than 21 mmHg, IOP reduction of at least 20% reduction from baseline, and no secondary surgical interventions. Outcomes were measured at 1, 3, 6, 12, 18, and 24 months.

RESULTS

A total of 165 AIT could be matched to 165 TRAB. The mean baseline IOP was 22.3 ± 5.6 mmHg, and the baseline number of glaucoma medications was 2.7 ± 1.1 in both groups. At 24 months, IOP was reduced to 15.8 ± 5.2 mmHg in AIT and 12.4 ± 4.7 mmHg in TRAB. IOP was lower than baseline at all visits (p < 0.01) and lower in TRAB than AIT (p < 0.01). Glaucoma medications were reduced to 2.1 ± 1.3 in AIT and 0.2 ± 0.8 in TRAB. Compared to baseline, patients used fewer drops postoperatively (p < 0.01) and more infrequently in TRAB than in AIT (p > 0.01). Secondary surgical interventions had the highest impact on success and became necessary in 15 AIT and 59 TRAB patients. Thirty-two challenging events occurred in TRAB and none in AIT.

CONCLUSION

Both AIT and TRAB reduced IOP and medications. This reduction was more significant in TRAB but at the expense of four times as many secondary interventions.

Combining Baerveldt Implant with Trabectome Negates Tube Fenestration: A Coarsened-matched Comparison

Purpose

To assess the efficacy and survival rate of the Trabectome-mediated ab interno trabeculectomy combined with non-fenestrated Baerveldt glaucoma implant compared with the Baerveldt glaucoma implant alone.

Methods

In this retrospective comparative case series, 175 eyes undergoing primary glaucoma surgery (Baerveldt–Trabectome [BT] group: 60 eyes and Baerveldt [B] group: 115 eyes) were included. Participants were identified using the procedural terminology codes. Groups were then matched by Coarsened Exact Matching that resulted in the inclusion of 51 eyes in each group. The primary outcome measure was surgical success defined as 5 mmHg < intraocular pressure (IOP) ≤ 21 mmHg, and IOP reduction ≥ 20% from baseline, and no need to reoperation for glaucoma. Secondary outcome measures were IOP, number of glaucoma medications, and best-corrected visual acuity (BCVA).

Results

The cumulative probability of success at one year was 61% in the BT group and 50% in the B group. IOP decreased from 23.5 ± 2.4 mmHg at baseline to 14.1 ± 2.7 mmHg at the final follow-up in the BT group (P = 0.001). The corresponding values for the B group were 23.2 ± 2.0 mmHg and 13.9 ± 1.6 mmHg, respectively (P = 0.001). There was no significant difference between the groups in terms of IOP at the final follow-up (P = 0.56). The number of medications at baseline was 2.3 ± 0.3 in both groups. However, the BT group needed fewer drops at all postoperative time intervals and used 1.1 ± 0.3 versus 2.0 ± 0.4 eye drops (group B) at the final follow-up visit (P = 0.004). Eyes in B with phacoemulsification had a significantly higher IOP on day 1 compared to B (23.2 ± 14.3 versus 17.9 ± 11.4, P = 0.041). During the one-year follow-up, 7 (13.7%) patients in BT group and 18 (35.2%) in B group experienced hypotony (P = 0.04). No dangerous hypotony or hypertension occurred in BT group. The mean BCVA at baseline was 0.64 ± 0.85 logMAR and changed to 0.55 ± 0.75 logMAR in BT and B groups, respectively (P = 0.663). The corresponding numbers for the final follow-up visit was 0.72 ± 1.07 and 0.63 ± 0.97 logMAR, respectively (P = 0.668).

Conclusion

We observed similar rates of success and IOP reduction using BT and B techniques. BT group needed fewer glaucoma medications. Tube fenestration was unnecessary in BT group resulting in less postoperative ocular hypotony and hypertension. The results of our study indicate that additional trabectome procedure makes Baerveldt glaucoma implant safer, easier to handle, and more predictable in the most vulnerable patients with advanced glaucoma.

Comparison of a second-generation trabecular bypass (iStent inject) to ab interno trabeculectomy (Trabectome) by exact matching

Purpose

To achieve a highly balanced comparison of trabecular bypass stenting (IS2, iStent inject) with ab interno trabeculectomy (T, Trabectome) by exact matching.

Methods

Fifty-three IS2 eyes were matched to 3446 T eyes. Patients were matched using exact matching by baseline intraocular pressure (IOP), the number of glaucoma medications, and glaucoma type, and using nearest neighbor matching by age. Individuals without a close match were excluded. All surgeries were combined with phacoemulsification.

Results

A total of 78 eyes (39 in each group) could be matched as exact pairs with a baseline IOP of 18.3 ± 5.1 mmHg and glaucoma medications of 2.7 ± 1.2 in each. IOP in IS2 was reduced to 14.6 ± 4.2 mmHg at 3 months and in T to a minimum of 13.1 ± 3.2 mmHg at 1 month. In IS2, IOP began to rise again at 6 months, eventually exceeding baseline. At 24 months, IOP in IS2 was 18.8 ± 9.0 mmHg and in T 14.2 ± 3.5 mmHg. IS2 had a higher average IOP than T at all postoperative visits (p < 0.05 at 1, 12, 18 months). Glaucoma medications decreased to 2.0 ± 1.5 in IS2 and to 1.5 ± 1.4 in T.

Conclusion

T resulted in a larger and sustained IOP reduction compared with IS2 where a rebound occurred after 6 months to slightly above preoperative values.

Two-year data comparison of ab interno trabeculectomy and trabecular bypass stenting using exact matching

PURPOSE

To create a balanced comparison of ab interno trabeculectomy (AIT) (Trabectome) and trabecular bypass stenting (TBS) (iStent).

SETTING

Eye and Ear Institute, Pittsburgh, Pennsylvania, Ross Eye Institute, Buffalo, New York, and Glaucoma Associates of Texas, Dallas, USA.

DESIGN

Retrospective case series.

METHODS

The primary outcome measure was an unmedicated intraocular pressure (IOP) of 21 mm Hg or less and the secondary measure was an unmedicated IOP reduction of 20% or more at 2 years. Patients were matched by baseline IOP, number of glaucoma medications, and glaucoma type using exact matching and by age using nearest neighbor matching. Individuals without a close match were excluded. All surgeries were combined with phacoemulsification.

RESULTS

One hundred fifty-four AIT eyes and 110 TBS eyes were analyzed. Forty-eight AIT patients were exactly matched with 48 TBS patients. Both groups had a mean baseline IOP of 15.3 mm Hg ± 3.1 (SD). At 24 months, the mean IOP was 13.9 ± 3.3 mm Hg in AIT patients and 16.8 ± 2.8 mm Hg in TBS patients and the mean number of medications was 0.7 ± 1.0 and 1.7 ± 1.2, respectively (both P = .04). At 24 months, the IOP was 21 mm Hg or less without medications in 53% of AIT patients and 16.6% of TBS patients (P < .05). At that time, 17.6% of patients in the AIT group but no patient in the TBS group had an IOP reduction of 20% or more without medication.

CONCLUSION

An exact matching comparison of AIT and TBS showed greater IOP reduction with fewer medications after AIT.

Comparing the trabecular outflow by the response to topical pilocarpine in patients with and without glaucoma filtering surgery

PURPOSE

To compare the trabecular outflow by the response to topical pilocarpine administration in patients with and without prior glaucoma filtering surgery.

STUDY DESIGN

Prospective, cross-sectional, randomized, double-blinded study.

METHODS

Open-angle glaucoma (OAG) patients without any prior glaucoma surgery, and those with prior trabeculectomy or tube shunt surgery aged 18-90 years were included. Both groups were randomized into pilocarpine or artificial tears (ATs). Intraocular pressure (IOP) was measured before and 90 min after the instillation of eye drops.

RESULTS

A total of 189 eyes of 189 patients were included: 92 eyes in the pilocarpine and 97 eyes in the ATs group. There was a mean ± standard deviation of - 0.81 ± 3.08 mmHg decrease in IOP with pilocarpine in those without prior surgery, significantly higher than the ATs group (0.55 ± 2.31 mmHg; p = 0.02). No significant change in IOP with pilocarpine was noted in the surgical group compared to the ATs group (p = 0.90). In the surgery group, greater IOP reduction was observed with pilocarpine in those who had undergone surgery within the last three years than those who had surgery three or more years prior (- 1.56 ± 2.64 versus 1.41 ± 2.77 mmHg; p = 0.001).

CONCLUSION

Less IOP reduction was observed with pilocarpine in patients who had filtering surgery more than three years previously compared to those with more recent surgery.

3D-Reconstruction of the human conventional outflow system by ribbon scanning confocal microscopy

PURPOSE

The risk for glaucoma is driven by the microanatomy and function of the anterior segment. We performed a computation-intense, high-resolution, full-thickness ribbon-scanning confocal microscopy (RSCM) of the outflow tract of two human eyes. We hypothesized this would reveal important species differences when compared to existing data of porcine eyes, an animal that does not spontaneously develop glaucoma.

METHODS

After perfusing two human octogenarian eyes with lectin-fluorophore conjugate and optical clearance with benzyl alcohol benzyl benzoate (BABB), anterior segments were scanned by RSCM and reconstructed in 3D for whole-specimen rendering. Morphometric analyses of the outflow tract were performed for the trabecular meshwork (TM), limbal, and perilimbal outflow structures and compared to existing porcine data.

RESULTS

RSCM provided high-resolution data for IMARIS-based surface reconstruction of outflow tract structures in 3D. Different from porcine eyes with an abundance of highly interconnected, narrow, and short collector channels (CCs), human eyes demonstrated fewer CCs which had a 1.5x greater cross-sectional area (CSA) and 2.6x greater length. Proximal CC openings at the level of Schlemm's canal (SC) had a 1.3x larger CSA than distal openings into the scleral vascular plexus (SVP). CCs were 10.2x smaller in volume than the receiving SVP vessels. Axenfeld loops, projections of the long ciliary nerve, were also visualized.

CONCLUSION

In this high-resolution, volumetric RSCM analysis, human eyes had far fewer outflow tract vessels than porcine eyes. Human CCs spanned several clock-hours and were larger than in porcine eyes. These species differences may point to factors downstream of the TM that increase our vulnerability to glaucoma.

Dose-dependent effects of netarsudil, a Rho-kinase inhibitor, on the distal outflow tract

PURPOSE

To characterize the effects of netarsudil on the aqueous humor outflow tract distal to the trabecular meshwork (TM). We hypothesized that netarsudil increases outflow facility in eyes with and without circumferential ab interno trabeculectomy (AIT) that removes the TM.

METHODS

Sixty-four porcine anterior segment cultures were randomly assigned to groups with (n = 32) and without circumferential AIT (n = 32). Cultures were exposed to 0.1, 1, and 10 μM netarsudil (N = 8 eyes per concentration). For each concentration, IOP and vessel diameters were compared with their respective pretreatment baselines. Outflow tract vessel diameters were assessed by spectral-domain optical coherence tomography (SDOCT) and rendered in 4D (XYZ time series).

RESULTS

Netarsudil at 1 μM reduced IOP both in eyes with TM (- 0.60 ± 0.24 mmHg, p = 0.01) and in eyes without TM (- 1.79 ± 0.42 mmHg, p < 0.01). At this concentration, vessels of the distal outflow tract dilated by 72%. However, at 0.1 μM netarsudil elevated IOP in eyes with TM (1.59 ± 0.36 mmHg, p < 0.001) as well as in eyes without TM (0.23 ± 0.32 mmHg, p < 0.001). Vessels of the distal outflow tract constricted by 31%. Similarly, netarsudil at a concentration of 10 μM elevated IOP both in eyes with TM (1.91 ± 0.193, p < 0.001) and in eyes without TM (3.65 ± 0.86 mmHg, p < 0.001). At this concentration, outflow tract vessels constricted by 27%.

CONCLUSION

In the porcine anterior segment culture, the dose-dependent IOP changes caused by netarsudil matched the diameter changes of distal outflow tract vessels. Hyper- and hypotensive properties of netarsudil persisted after TM removal.

Intraocular pressure reduction in a pigmentary glaucoma model by Goniotome Ab interno trabeculectomy

PURPOSE

To investigate whether microsurgical excision of trabecular meshwork (TM) in an ex vivo pigmentary glaucoma model can normalize the hypertensive phenotype.

METHODS

Eight eyes of a porcine pigmentary glaucoma model underwent 90° of microsurgical TM excision with an aspirating dual-blade (Goniotome (G)). 24 hours later, additional 90° of TM were removed. Anterior segments with sham surgeries served as the control (C). Outflow facility and intraocular pressure (IOP) were analyzed. Histology with hematoxylin and eosin (H&E) was obtained.

RESULTS

After the first 90° TM excision, IOP was significantly lower in G (10.2±2.4 mmHg, n = 7) than C (20.0±2.0mmHg, n = 8, P<0.01). Outflow facility in G (0.38±0.07 μl/min/mmHg) was higher than C (0.16±0.02 μl/min/mmHg, P<0.01). After the second 90° TM excision, IOP in G (6.46±0.81 mmHg, n = 7) was significantly lower than C (20.3±1.7 mmHg, n = 8, P<0.001), while the outflow facility in G (0.50±0.05 μl/min/mmHg, n = 7) was higher than C (0.16±0.01 μl/min/mmHg, n = 8, P<0.001). Compared to the first excision, excision of an additional 90° did not change of IOP (P = 0.20) or outflow facility (P = 0.17) further.

CONCLUSIONS

Excision of 90° of TM in a pigmentary glaucoma model using an aspirating dual-blade decreased IOP and increased outflow facility.

Microsurgical scleral drainage and trabeculectomy-scleral flap adjustable suture combination technique in the treatment of primary glaucoma

Objective:

To investigate the clinical effect of microsurgical scleral drainage and trabeculectomy combined with scleral flap adjustable suture technique in the treatment of primary glaucoma.

Methods:

One hundred primary glaucoma patients (120 eyes) in Xinyu People’s Hospital of Jiangxi province were selected from July 2014 to June 2016. The patients were randomly divided into control group and study group. The control group was treated with compound trabeculectomy, while the study group was treated with microsurgical scleral drainage and trabeculectomy combined with scleral flap adjustable suture technique. In both groups of patients, intraocular pressure, functional filtering bleb formation, and complications before and after surgery were monitored for three days, one week, one month, three months, six months and one year, while anterior chamber depth was determined one week after operation. The extent of success of operation was compared between the two groups.

Results:

At three days, one week, one month, three months, six months and one year after surgery, intraocular pressure of study group was significantly lower than that of the control group (P<0.05). There was 93.33% formation of functional filtering blebs in the study group, which was significantly higher than that in the control group (60.00%, P<0.001). Moreover, normal anterior chamber formation was significantly higher in the study group (91.67%) than in the control group (71.67%, P<0.01). There was 95.00% operation success in the study group, relative to 68.33% success in the control group (P<0.001).

Conclusion:

Microsurgical scleral drainage and trabeculectomy combined with scleral flap adjustable suture technique has better curative effect on primary glaucoma than compound trabeculectomy. Moreover, it does not exacerbate complications. Therefore, the combination treatment technique merits clinical application.

The Influence of Trabectome Surgery on Corneal Endothelial Cells

PURPOSE

The purpose of this study was to evaluate the influence of trabectome surgery on corneal endothelial cells by site.

METHODS

Retrospective observational study. Trabectome surgeries were performed on 159 eyes of 132 adult Japanese patients. Corneal endothelial cells were measured at the center (C), inferior (I), nasal inferior (NI), nasal superior (NS), superior (S), temporal superior (TS), and temporal inferior (TI) sectors at <1 month preoperatively and 3, 6, 12, 24, and 36 months postoperatively, for changes in corneal endothelial cell density (ECD), coefficient of variation (CV), and incidence of hexagonal cells (6A).

RESULTS

Mean preoperative ECD in all groups were 2401±451 (SD)  cells/mm (C), 2366±450 cells/mm (I), 2397±479 cells/mm (NI), 2476±554 cells/mm (NS), 2493±596 cells/mm (S), 2464±558 cells/mm (TS), and 2329±510 cells/mm (TI). The 12-month postoperative mean ECDs were 2344±480 cells/mm (C), 2312±469 cells/mm (I), 2325±536 cells/mm (NI), 2473±517 cells/mm (NS), 2438±607 cells/mm (S), 2227±578 cells/mm (TS), and 2193±523 cells/mm (TI). There was no change in ECD in all sectors before and after surgery. ECD decreased at the TS and TI in combination with cataract surgery (2620±430 and 2445±384 cells/mm) preoperatively to 2264±501 and 2216±477 cells/mm at 12 months postoperatively. CV and 6A did not change at all sites in all surgical procedures before and after surgery.

CONCLUSIONS

Trabectome surgery involves minimal effects to corneal endothelial cells, although long-term prospective studies with greater sample sizes are necessary to confirm this conclusion.

Prospective Studies of Minimally Invasive Glaucoma Surgeries: Systematic Review and Quality Assessment

Glaucoma is a common blinding disease; while there is no cure, effective treatments include medications, laser, and incisional surgery. There is significant interest from patients and doctors to develop safer surgical options throughout the spectrum of disease, to minimize treatment burden in mild glaucoma patients and to minimize risk of complications in patients needing more aggressive treatment. Surgical procedures called Minimally or Micro-Invasive Glaucoma Surgery (MIGS) are growing in popularity. Eighty-seven prospective studies on MIGS were identified and assessed for quality. Most (74%) did not have a control group. Twelve of the highest quality were reviewed. MIGS procedures appeared to have fewer complications, and lowered intraocular pressure, and reduced medication use. Studies were limited by small sample size, narrow spectrum of glaucomatous disease, and/or conflicts of interest. There is a need for high quality, independently funded and performed, comparative studies on the MIGS to help make treatment decisions.

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.

Structure-Function Changes of the Porcine Distal Outflow Tract in Response to Nitric Oxide

Purpose

To correlate outflow function and outflow tract vessel diameter changes induced by nitric oxide (NO).

Methods

In a porcine anterior segment perfusion model, the effects of a nitric oxide donor (100 μM DETA-NO) on outflow facility were compared with controls (n = 8 per group) with trabecular meshwork (TM) and after circumferential ab interno trabeculectomy (AIT). Outflow structures were assessed with spectral-domain optical coherence tomography (SD-OCT) before and after NO, or an NO synthase inhibitor (100 μM L-NAME) and the vasoconstrictor, endothelin-1 (100 pg/mL ET-1). Scans were processed with a custom macroscript and aligned for automated reslicing and quantification of cross-sectional outflow tract areas (CSA).

Results

The facility increased after DETA-NO (Δ of 0.189 ± 0.081 μL/min·mm Hg, P = 0.034) and AIT (Δ of 0.251 ± 0.094 μL/min·mm Hg, P = 0.009), respectively. Even after AIT, DETA-NO increased the facility by 61.5% (Δ of 0.190 ± 0.074 μL/min·mm Hg, P = 0.023) and CSA by 13.9% (P < 0.001). L-NAME + ET-1 decreased CSA by -8.6% (P < 0.001). NO increased the diameter of focal constrictions 5.0 ± 3.8-fold.

Conclusions

NO can dilate vessels of the distal outflow tract and increase outflow facility in a TM-independent fashion. There are short, focally constricting vessel sections that display large diameter changes and may have a substantial impact on outflow.

High-Resolution, Three-Dimensional Reconstruction of the Outflow Tract Demonstrates Segmental Differences in Cleared Eyes

Purpose

The rate of conventional aqueous humor outflow is the highest nasally. We hypothesized that this is reflected in regionally different outflow structures and analyzed the entire limbus by high-resolution, full-thickness ribbon-scanning confocal microscopy (RSCM).

Methods

We perfused pig eyes by anterior chamber cannulation with eight lectin-fluorophore conjugates, followed by optical clearance with benzyl alcohol benzyl benzoate (BABB). RSCM and advanced analysis software (Imaris) were used to reconstruct a three-dimensional (3D), whole-specimen rendering of the perilimbal outflow structures. We performed morphometric analyses of the outflow tract from the level of the trabecular meshwork (TM) to the scleral vascular plexus (SVP).

Results

Except for pigmented structures, BABB cleared the entire eye. Rhodamine-conjugated Glycine max agglutinin (soybean [SBA]) labeled the outflow tract evenly and retained fluorescence for months. RSCM produced terabyte-sized files allowing for in silico dissection of outflow tract vessels at a high resolution and in 3D. Networks of interconnected lumens were traced from the TM to downstream drainage structures. The collector channel (CC) volumes were 10 times smaller than the receiving SVP vessels, the largest of which were in the inferior limbus. Proximal CC diameters were up to four times the size of distal diameters and more elliptical at their proximal ends. The largest CCs were found in the superonasal and inferonasal quadrants where the highest outflow occurs.

Conclusion

RSCM of cleared eyes enabled high-resolution, volumetric analysis of the outflow tract. The proximal structures had greater diameters nasally, whereas the SVP was larger in the inferior limbus.

Five-year clinical outcomes of combined phacoemulsification and trabectome surgery at a single glaucoma center

PURPOSE

To analyze the 5-year results of trabectome ab interno trabeculectomy of a single glaucoma center.

METHOD

In this retrospective interventional single-center case series, data of 93 patients undergoing ab interno trabeculotomy between September 2010, and December 2012 were included. Kaplan-Meier analysis was performed using success criteria defined as postoperative intraocular pressure (IOP) ≤ 21 mmHg, and > 20% reduction from preoperative IOP, and no need for further glaucoma surgery. Risk factors for failure were identified using Cox proportional hazards ratio (HR).

RESULTS

The retention rate for 5-year follow-up was 66%. The cumulative probability of success at 1, 2, 3, 4, and 5 years was 82.6%, 76.7%, 73.9%, 72.3%, and 67.5%. Risk factors for failure were lower baseline IOP (HR = 0.27, P = 0.001), younger age (HR = 0.25, P = 0.02), and higher central corneal thickness (HR = 0.18, P = 0.01). Exfoliative glaucoma was associated with a higher success rate (HR = 0.39, P = 0.02). IOP was decreased significantly from 20.0 ± 5.6 mmHg at baseline to 15.6 ± 4.6 mmHg at 5-year follow-up (P = 0.001). The baseline number of glaucoma medications was 1.8 ± 1.2, which decreased to 1.0 ± 1.2 medications at 5 years.

CONCLUSION

Trabectome surgery was associated with a good long-term efficacy and safety profile in this single-center case series with a high retention rate.

Extended pharmacological miosis is superfluous after glaucoma angle surgery: A retrospective study

Background: Pilocarpine is commonly used after angle surgery for glaucoma despite a host of side effects and risks. We hypothesized that a pharmacological miosis during the first two months does not improve short- and long-term results of trabectome-mediated ab interno trabeculectomy.

Methods: In this retrospective comparative 1-year case series, we compared 187 trabectome surgery eyes with (P+) or without (P-) 1% pilocarpine for two months. Primary outcome measures were the surgical success defined as intraocular pressure (IOP) ≤ 21 mmHg and decreased ≥ 20%, and no secondary glaucoma surgery. Secondary outcome measures were the number of glaucoma medications, complications, and IOP.

Results: We categorized 86 (46%) eyes as P- and 101 (54%) eyes as P+. The mean age was 69.8±10.1 in P- and 70.5±9.4 in P+ (P=0.617) with equal gender distribution (P=0.38). The cumulative probability of qualified success at 12 months was 78.1% in the P- and 81% in the P+ (P=0.35). The IOP was decreased significantly from 20.2±6.8 mmHg at baseline to 15.0±4.8 mmHg at 12 months follow-up in P- (P=0.001) and 18.8±5.3 and 14.7±4.0, respectively (P=0.001). The medications decreased significantly from 1.4±1.2 in P- and 1.4±1.2 in P+ at baseline to 1.0±1.2 and 0.7±1.0, respectively (P=0.183). P- and P+ did not differ in IOP or medications (all P>0.05). In Multivariate Cox Regression models, the baseline IOP and central corneal thickness were associated with failure.

Conclusions:Use of postoperative pilocarpine does not improve the efficacy of trabectome surgery.

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.

iStent inject as a reasonable alternative procedure following failed trabeculectomy?

PURPOSE:

The aim of this study is to assess the intraocular pressure lowering effect and the performance of the glaucoma therapy of the iStent inject in glaucoma patients with uncontrolled intraocular pressure after failed trabeculectomy.

METHODS:

In this retrospective study, iStent inject implantation (Glaukos Corporation, Laguna Hills, CA, USA) was performed in 22 eyes of 21 subjects suffering from glaucoma (n = 18 primary open angle glaucoma, n = 3 pseudoexfoliation glaucoma, and n = 1 for secondary glaucoma) with an intraocular pressure above target pressure after failed trabeculectomy (mean = 9.6 ± 8.1 years; range: 1-35 years). The intraocular pressure and the number of antiglaucomatous medication were assessed preoperatively, 1 day, 6 weeks, 3 months, 6 months, and 1 year after surgery and compared to preoperative findings (SPSS v23.0; Shapiro-Wilk test, Wilcoxon test, Friedman test).

RESULTS:

The results showed a significant intraocular pressure decrease from 22.5 ± 4.6 to 15.5 ± 3.4 mmHg after 1 year follow-up (p = 0.012). The glaucoma therapy was 2.6 ± 1.2 preoperatively and reduced to 2.25 ± 1.5 number of medications after 1 year (p > 0.05). There was no significant difference in the number of medication during the whole follow-up period (1 year, p = 0.012). No significant intra- or postoperative complications were reported.

CONCLUSION:

Minimal invasive glaucoma surgery (iStent inject) can offer an effective intraocular pressure reduction in advanced adult primary and secondary open angle glaucoma after failed trabeculectomy in a follow-up period of 1 year. Glaucoma therapy, however, needs to be maintained to achieve an individual target pressure and to prevent glaucoma progression. In addition, a failure rate of 27.3% makes it necessary to select carefully patients for this treatment option.

Ab Interno Trabeculectomy With the Trabectome as a Valuable Therapeutic Option for Failed Filtering Blebs

PURPOSE

Uncontrolled intraocular pressure (IOP) after glaucoma filtration surgery is a challenging problem in the management of glaucoma patients. The Trabectome is a device for selective electroablation of the trabecular meshwork through a clear cornea incision without affecting the conjunctiva. Minimally invasive glaucoma surgery using the Trabectome is safe and effective as primary glaucoma surgery. Here we investigate the results of ab interno trabeculectomy with the Trabectome for IOP control in patients with a failed filtering bleb.

METHODS

A total of 60 eyes of 60 consecutive patients with primary open-angle glaucoma (POAG) or pseudoexfoliative glaucoma (PXG) were enrolled in this single center observational study. Trabectome surgery was performed alone or in combination with phacoemulsification by 2 experienced surgeons. IOP readings and number of IOP lowering medication as primary outcome parameters were taken by an independent examiner. Intraoperative and postoperative medication were recorded systematically.

RESULTS

Mean IOP before surgery was 24.5±3.5 mm Hg and decreased to 15.7±3.4 (-36%) after mean follow-up of 415 days. The number of necessary IOP lowering medication dropped from 2.1±1.3 to 1.8±1.2 (14% reduction from baseline). A total of 25% (n=15) of cases reported here needed additional surgery after 517 days (range: 6 to 1563 d). No major complications were observed. After mean follow-up, we found a qualified success rate for PXG of 87% and 50% for POAG as revealed by the Kaplan-Meier analysis according to the definitions for success in advanced glaucoma cases according to the World Glaucoma Association (40% reduction from baseline IOP and maximum IOP of 15 mm Hg).

DISCUSSION

Trabectome surgery for uncontrolled IOP after trabeculectomy is safe and effective especially in PXG patients. Given the demanding subgroup of patients studied here, it is not surprising that success rates are lower compared with previous studies investigating the Trabectome for primary glaucoma surgery. The number of necessary IOP lowering medication drops at first, but seems to reach preoperative values after 20 months of follow-up. Trabectome surgery should be considered as a valuable escape procedure for patients with failed filtering blebs and uncontrolled IOP.

Longer-term Baerveldt to Trabectome glaucoma surgery comparison using propensity score matching

PURPOSE

To apply propensity score matching to compare Baerveldt glaucoma drainage implant (BGI) to Trabectome-mediated ab interno trabeculectomy (AIT). Recent data suggests that AIT can produce results similar to BGI which is traditionally reserved for more severe glaucoma.

METHODS

BGI and AIT patients with at least 1 year of follow-up were included. The primary outcome measures were intraocular pressure (IOP), number of 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, gender, type of glaucoma, concurrent phacoemulsification, baseline number of medications, and baseline IOP. Patients with neovascular glaucoma, with prior glaucoma surgery, or without a close match were excluded.

RESULTS

Of 353 patients, 30 AIT patients were matched to 29 BGI patients. Baseline characteristics including, IOP, the number of glaucoma medications, type of glaucoma, the degree of VF loss and GI were not significantly different between AIT and BGI. BGI had a preoperative IOP of 21.6 ± 6.3 mmHg compared to 21.5 ± 7.4 for AIT on 2.8 ± 1.1 medications and 2.5 ± 2.3 respectively. At 30 months, the mean IOP was 15.0 ± 3.9 mmHg for AIT versus 15.0 ± 5.7 mmHg for BGI (p > 0.05), while the number of drops was 1.5 ± 1.3 for AIT (change: p = 0.001) versus 2.4 ± 1.2 for BGI (change: p = 0.17; AIT vs BGI: 0.007). Success, defined as IOP < 21 mmHg, < 20% reduction and no reoperation, was achieved at 1 year in 56% of AIT versus 55% of BGI (p > 0.05) and 50% versus 52% at 2.5 years.

CONCLUSIONS

A propensity score matched comparison of AIT and BGI demonstrated a similar IOP reduction through 1 year. AIT required fewer medications.

Quantification of Focal Outflow Enhancement Using Differential Canalograms

Purpose

To quantify regional changes of conventional outflow caused by ab interno trabeculectomy (AIT).

Methods

Gonioscopic, plasma-mediated AIT was established in enucleated pig eyes. We developed a program to automatically quantify outflow changes (R, package eye-canalogram, github.com) using a fluorescent tracer reperfusion technique. Trabecular meshwork (TM) ablation was demonstrated with fluorescent spheres in six eyes before formal outflow quantification with two-dye reperfusion canalograms in six additional eyes. Eyes were perfused with a central, intracameral needle at 15 mm Hg. Canalograms and histology were correlated for each eye.

Results

The pig eye provided a model with high similarity to AIT in human patients. Histology indicated ablation of TM and unroofing of most Schlemm's canal segments. Spheres highlighted additional circumferential and radial outflow beyond the immediate area of ablation. Differential canalograms showed that AIT caused an increase of outflow of 17 ± 5-fold inferonasally, 14 ± 3-fold superonasally, and also an increase in the opposite quadrants with a 2 ± 1-fold increase superotemporally, and 3 ± 3 inferotemporally. Perilimbal specific flow image analysis showed an accelerated nasal filling with an additional perilimbal flow direction into adjacent quadrants.

Conclusions

A quantitative, differential canalography technique was developed that allows us to quantify supraphysiological outflow enhancement by AIT.

Trabectome success factors

Our objective is to investigate which factors and patient characteristics are associated with success in Trabectome surgery.A total of 658 phakic cases with at least of 12 months follow-up were included in the analysis. Baseline demographics and medical data were collected. The main outcome measure was intraocular pressure (IOP), glaucoma medication (Rx), and secondary glaucoma surgery if any. Success was defined as IOP reduction of 20% or more from preoperative IOP and IOP < 21 mm Hg with no secondary surgery throughout the follow-up period. Risk factors for failure were determined by using univariate and multivariate cox regression.At baseline, the average IOP was 23.6 ± 7.8 mm Hg and the average number of medications was 2.6 ± 1.3 for all cases. At 12 months, the average IOP was 16.0 ± 3.6 mm Hg (P < .01) and the average number of medications was 1.8 ± 1.3 (P < .01). Based on the result of multivariate cox regression model, we found that the Trabectome + Phaco (TP) and Trabectome alone (TA) group had a 94% and 79% survival rate at 12 months, respectively. TP cases had 78% lower risk of failure than TA (95% confidence interval [CI]: 54-89), diagnosis of pseudoexfoliation glaucoma had a 54% lower risk of failure than primary open angle glaucoma patients (95% CI: 1-78). Hispanics had an estimated hazard ratio that is 60% lower than Caucasians (95% CI: 18-80); 20% of TA cases and 3% of TP cases were required to undergo additional secondary surgery (P < .01).Trabectome surgery, whether in combination with phacoemulsification cataract removal or stand alone, is associated with a significant reduction of IOP and glaucoma medication. Patients having a higher baseline IOP are expected to have a higher IOP reduction after Trabectome. Pseudoexfoliation glaucoma, combination with phacoemulsification cataract surgery and Hispanic race are factors associated with enhanced Trabectome survival.

Rapid learning curve assessment in an ex vivo training system for microincisional glaucoma surgery

Increasing prevalence and cost of glaucoma have increased the demand for surgeons well trained in newer, microincisional surgery. These procedures occur in a highly confined space, making them difficult to learn by observation or assistance alone as is currently done. We hypothesized that our ex vivo outflow model is sensitive enough to allow computing individual learning curves to quantify progress and refine techniques. Seven trainees performed nine trabectome-mediated ab interno trabeculectomies in pig eyes (n = 63). An expert surgeon rated the procedure using an Operating Room Score (ORS). The extent of outflow beds accessed was measured with canalograms. Data was fitted using mixed effect models. ORS reached a half-maximum on an asymptote after only 2.5 eyes. Surgical time decreased by 1.4 minutes per eye in a linear fashion. The ablation arc followed an asymptotic function with a half-maximum inflection point after 5.3 eyes. Canalograms revealed that this progress did not correlate well with improvement in outflow, suggesting instead that about 30 eyes are needed for true mastery. This inexpensive pig eye model provides a safe and effective microsurgical training model and allows objective quantification of outcomes for the first time.

Safety and Efficacy of Microinvasive Glaucoma Surgery

Microinvasive glaucoma surgery (MIGS) is emerging as a new therapeutic option for glaucoma patients who wish to reduce their medication burden and avoid the postoperative complications of conventional glaucoma filtration surgery. These devices differ in terms of their efficacy and safety profile. Schlemm's canal devices have the most favorable safety profile at the compromise of modest efficacy, while subconjunctival and suprachoroidal devices are potentially more effective at lowering the intraocular pressure at the expense of a higher rate of complications. This review consolidates the latest evidence on the efficacy and safety of the MIGS devices in clinical use and provides an overview on upcoming devices which would likely also become viable treatment options in the near future. These clinical data would assist a glaucoma surgeon in selecting the most appropriate MIGS device for each patient based on the glaucoma severity and patient expectations.

Stratification of phaco-trabectome surgery results using a glaucoma severity index in a retrospective analysis

Background

To stratify the outcomes of phacoemulsification combined with trabectome surgery using a new glaucoma severity index.

Methods

This is a retrospective, observational cohort study that included open angle glaucoma patients with visually significant cataract that had phacoemulsification combined with trabectome surgery. Exclusion criteria were follow-up less than 12 months, any other surgeries or diagnosis of neovascular or active uveitic glaucoma. Patients were stratified into four groups according to the Glaucoma Index (GI) that incorporated preoperative intraocular pressure (IOP), number of medications and visual field status. The primary outcome measures were IOP reduction and the success rate at 12 months. We examined the relationship between GI group and IOP and medications at one year with a linear regression analysis and survival with log-rank testing.

Results

Of 1374 patients, a total of 498 cases with 12 month follow-up were included in the study after applying the exclusion criteria. At one year, IOP of GI groups 1 through 4 was reduced by 2.9 ± 4.4, 3.6 ± 5.0, 3.9 ± 5.3, and 9.2 ± 7.6 mmHg for. Individuals in the next higher GI group had a 1.69 ± 0.2 mmHg larger IOP decrease. The success rate was 98%, 93%, 96% and 88% at one year for GI groups 1 to 4 (p < 0.05).

Conclusions

A substantial IOP reduction was seen in subjects with more advanced glaucoma suggesting that the trabecular meshwork is the primary impediment to outflow and its ablation benefits those eyes relatively more than in mild glaucoma. A larger IOP reduction can be expected in individuals with a higher GI group that indicates a clinically more challenging glaucoma.

Training strategies and outcomes of ab interno trabeculectomy with the trabectome

Plasma-mediated ab interno trabeculectomy with the trabectome was first approved by the US Food and Drug Administration in 2004 for use in adult and pediatric glaucomas. Since then, increased clinical experience and updated outcome data have led to its expanded use, including a range of glaucomas and angle presentations, previously deemed to be relatively contraindicated. The main benefits are a high degree of safety, ease, and speed compared to traditional filtering surgery and tube shunts. The increasing burden of glaucoma and expanding life expectancy has resulted in demand for well-trained surgeons. In this article, we discuss the results of trabectome surgery in standard and nonstandard indications. We present training strategies of the surgical technique that include a pig eye model, and visualization exercises that can be performed before and at the conclusion of standard cataract surgery in patients who do not have glaucoma. We detail the mechanism of enhancing the conventional outflow pathway and describe methods of visualization and function testing.

Training strategies and outcomes of ab interno trabeculectomy with the trabectome

Plasma-mediated ab interno trabeculectomy with the trabectome was first approved by the US Food and Drug Administration in 2004 for use in adult and pediatric glaucomas. Since then, increased clinical experience and updated outcome data have led to its expanded use, including a range of glaucomas and angle presentations, previously deemed to be relatively contraindicated. The main benefits are a high degree of safety, ease, and speed compared to traditional filtering surgery and tube shunts. The increasing burden of glaucoma and expanding life expectancy has resulted in demand for well-trained surgeons. In this article, we discuss the results of trabectome surgery in standard and nonstandard indications. We present training strategies of the surgical technique that include a pig eye model, and visualization exercises that can be performed before and at the conclusion of standard cataract surgery in patients who do not have glaucoma. We detail the mechanism of enhancing the conventional outflow pathway and describe methods of visualization and function testing.

Long-term Effectiveness of Trabectome (Ab-interno Trabeculectomy) Surgery

Aim

To evaluate the long-term safety and efficacy of ab-interno trabeculectomy with trabectome for the treatment of glaucoma.

Materials and methods

Data collected for 339 eyes which included demographics, intraocular pressure (IOP) measurements using Goldmann applanation tonometry, best-corrected visual acuity (BCVA), visual field results, optic nerve status, gonioscopic findings, prior glaucoma procedures, number of glaucoma medications and pain level. The main data points of interest were preoperative IOP vs. postoperative IOP and BCVA, medication use, pain status, and complications.

Results

Of the 339 eyes that underwent trabectome, we found a statistically significant reduction in IOP (p < 0.01) at final follow-up (average = 18.35 months) of nearly 23%, with a complication rate of 5.86%. Furthermore, this reduction was maintained up to 8 years post procedure. LogMAR visual acuity was significantly improved in 69% of eyes at the final visit (p < 0.05), while only 1.77% of cases saw a significant reduction. Based on these findings, we determined a success rate of around 80% to 100 months following trabectome.

Conclusion

Trabectome is a safe and effective long term for most forms and severities of glaucoma.

How to cite this article

Bendel RE, Patterson MT. Long-term Effectiveness of Trabectome (Ab-interno Trabeculectomy) Surgery. J Curr Glaucoma Pract 2018;12(3):119-124.

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.

[Surgical options before and after trabectome surgery : Impact of previous surgeries, possibilities of revision surgery and complication management]

BACKGROUND

Trabectome surgery is a new method to lower intraocular pressure through ablation of the trabecular meshwork. Technically, it is an ab interno trabeculotomy. The goal of this review is to investigate the options after failed trabectome surgery and evaluate the possibilities of trabectome surgery after failed previous glaucoma surgery.

OBJECTIVES

A literature review was performed to answer the following questions: (1) Is trabectome surgery an option after failed glaucoma surgery? (2) Is trabeculectomy an option after failed trabectome surgery? (3) Which postoperative constellations require early revision surgery after trabectome surgery?

RESULTS

Trabectome surgery is an option after failed trabeculectomy or failed tube surgery. Performing a trabeculectomy after failed trabectome surgery did not show disadvantages. Hypotony or hyphema is rare and self-limiting and, therefore, does not require further surgery.

CONCLUSIONS

Due to a lack of randomized studies, recommendations should be taken with caution.

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.

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.

Combined analysis of trabectome and phaco-trabectome outcomes by glaucoma severity

Prior glaucoma severity staging systems were mostly concerned with visual field function and retinal nerve fiber layer, but did not include intraocular pressure or medications to capture resistance to treatment. We recently introduced a simple index that combines pressure, medications, and visual field damage and applied it to stratify outcomes of trabectome surgery. In the analysis presented here, we combined data of trabectome alone and trabectome with same session cataract surgery to increase testing power and chances of effect discovery. This microincisional glaucoma surgery removes the primary resistance to outflow in glaucoma, the trabecular meshwork, and has been mostly used in mild glaucoma. Traditional glaucoma surgeries have a relatively high complication rate and have been reserved for more advanced disease stages. In the analysis presented here we include our data of trabectome combined with cataract surgery. This is a common practice pattern as both occur in the same age group with increasing frequency. For patients in higher glaucoma index (GI) groups, the intraocular pressure (IOP) reduction was 2.34+/-0.19 mmHg more than those in a GI group one level lower while holding everything else constant. Those who had undergone trabectome combined with phacoemulsification had an IOP reduction that was 1.29+/-0.39 mmHg less compared to those with trabectome alone. No statistically significant difference was found between genders and age groups while holding everything else constant. Hispanics had a 3.81+/-1.08 mmHg greater IOP reduction. Pseudoexfoliation and steroid glaucoma patients had an IOP reduction that was greater by 2.91+/-0.56 and 3.86+/-0.81 mmHg, respectively, than those with primary open angle glaucoma. These results suggest a role for trabectome-mediated ab interno trabeculectomy beyond mild forms of glaucoma. Additionally, the multifactorial glaucoma index demonstrates a role in staging patients when comparing glaucoma surgical modalities.