Steroid-induced glaucoma treated with trabecular ablation in a matched comparison with primary open-angle glaucoma

Historical and Contemporary Debates in Schlemm's Canal-Based MIGS

Glaucoma is one of the primary causes of blindness worldwide. Canal opening surgery, a type of minimally invasive glaucoma surgery (MIGS) applied in cases of mild to moderate glaucoma, has gained increasing popularity in recent years due to its efficacy in reducing the intraocular pressure, its safety profile, the simplicity of its technique, and the reduced likelihood of compromised vision. Nevertheless, the existing body of histopathological studies remains insufficient for a comprehensive understanding of post-surgical wound healing. Consequently, debates persist among researchers regarding the mechanism through which Schlemm's canal opening surgery reduces the intraocular pressure, as well as the surgical techniques that may impact the outcomes and the factors influencing surgical success. As the history of MIGS is relatively short and lacks sufficient systemic reviews or meta-analyses evaluating the influence of individual factors, this review was conducted to illuminate the disparities in researchers' opinions at the current stage of research.

Characteristics of Eyes Requiring Trabeculotomy for Glaucoma With Steroid Treatment: Atopic Dermatitis and Factors Affecting Surgical Outcomes

PURPOSE

The aim is to analyze the surgical outcomes of glaucomatous patients with steroid treatment and investigate the factors, including atopic dermatitis, associated with the surgical success rate.

MATERIALS AND METHODS

We retrospectively enrolled participants who required first trabeculotomy for glaucoma with steroid treatment between May 2005 and February 2018 and then compared the postoperative outcomes according to the history of atopic dermatitis or surgical procedures. Surgical success was defined as postoperative IOP ≤ 21 mmHg, ≥20% reduction from baseline, and absence of reoperation. The factors influencing the surgical success rates were investigated using mixed-effects Cox regression.

RESULTS

The study included 70 eyes of 46 patients (18 eyes of 12 patients with atopic dermatitis). Postoperative intraocular pressure was not significantly different between eyes with and without atopic dermatitis (12 months after the surgery: patients without atopic dermatitis, 15.4 ± 3.6 mmHg; patients with atopic dermatitis, 16.1 ± 3.9 mmHg; P = 0.65). Twelve months after the surgery, the number of postoperative medications was higher in patients with atopic dermatitis than in those without (2.8 ± 1.3 vs. 2.0 ± 1.7; P = 0.060). However, no significant differences were noted in surgical success rates between patients with atopic dermatitis and those without (P = 0.54). Mixed-effects Cox regression of surgical success rate indicated that only the number of preoperative medications significantly influenced surgical success (P = 0.03).

CONCLUSIONS

Regardless of the presence of atopic dermatitis, patients taking many preoperative glaucomatous medications might require reoperation.

Gonioscopy-Assisted Transluminal Trabeculotomy and Goniotomy, With or Without Concomitant Cataract Extraction, in Steroid-Induced and Uveitic Glaucoma: 24-Month Outcomes

PRCIS

Gonioscopy-assisted transluminal trabeculotomy (GATT) and goniotomy with Kahook Dual Blade both achieved sustained reductions in intraocular pressure (IOP) and medication burden in eyes with steroid-induced or uveitic glaucoma at 24 months. Both procedures had favorable safety profiles.

PURPOSE

To characterize the 24-month surgical outcomes of GATT and excisional goniotomy in eyes with steroid-induced or uveitic glaucoma.

PATIENTS AND METHODS

A retrospective chart review was performed of eyes with steroid-induced or uveitic glaucoma that underwent GATT or excisional goniotomy, either standalone or combined with phacoemulsification cataract surgery, by a single surgeon at the Cole Eye Institute. IOP, number of glaucoma medications, and steroid exposure were recorded preoperatively and at multiple postoperative timepoints up to 24 months. Surgical success was defined as at least 20% IOP reduction or IOP <12, 15, or 18 mm Hg (Criterion A, B, or C). Surgical failure was defined as need for additional glaucoma surgery or loss of light perception vision. Intraoperative and postoperative complications were reported.

RESULTS

Forty eyes of 33 patients underwent GATT, and 24 eyes of 22 patients underwent goniotomy, of which 88% and 75%, respectively, had 24-months' follow-up. Concomitant phacoemulsification cataract surgery was performed in 38% (15/40) GATT eyes and 17% (4/24) goniotomy eyes. IOP and number of glaucoma medications were reduced at all postoperative timepoints in both groups. At 24 months, GATT eyes had mean IOP 12.9±3.5 mm Hg on 0.9±1.2 medications, and goniotomy eyes had mean IOP 14.3±4.1 mm Hg on 1.8±1.3 medications. Surgical failure was 8% for GATT and 14% for goniotomy at 24 months. Transient hyphema and transient IOP elevation were the most common complications, and 10% GATT eyes required surgical evacuation of hyphema.

CONCLUSIONS

Both GATT and goniotomy demonstrate favorable efficacy and safety in steroid-induced and uveitic glaucoma eyes. Both procedures achieved sustained reductions in IOP and glaucoma medication burden at 24 months.

Circumferential (360°) trabeculotomy for steroid-induced glaucoma in adults

PURPOSE

To evaluate the safety and efficacy of 360° circumferential trabeculotomy (TO) for steroid induced glaucoma (SIG) of short duration.

METHODS

Retrospective analysis of surgical results of 46 eyes of 35 patients undergoing microcatheter-assisted TO. All eyes had high intraocular pressure for at most about 3 years due to steroid use. Follow-up was between 2.63 and 47.9 months (mean 23.9, median 25.6).

RESULTS

Intraocular pressure (IOP) before surgery was 30.8 ± 8.3 mm Hg, with 3.8 ± 1.0 pressure-lowering medications. After 1 to 2 years, mean IOP was 11.2 ± 2.6 mm Hg (n = 28); mean number of IOP-lowering medications was 0.9 ± 1.3. At their last follow-up, 45 eyes had an IOP < 21 mm Hg, and 39 eyes had an IOP < 18 mm Hg with or without medication. After 2 years, the estimated probability of having an IOP below 18 mm Hg (with or without medication) was 85 ± 6%, and the estimated probability of not using medication was 56 ± 7%. Steroid response was no longer present in all eyes receiving steroids after surgery. Minor complications consisted of hyphema, transient hypotony, or hypertony. One eye proceeded to receiving a glaucoma drainage implant.

CONCLUSION

TO is particularly effective in SIG with relative short duration. This concurs with the pathophysiology of the outflow system. This procedure seems particularly suited for eyes for which target pressures in the mid-teens are acceptable, particularly when chronic use of steroids is necessary .

Coarsened Exact Matching of Excisional to Plasma-ablative Ab Interno Trabeculectomy

Aim

To compare ab interno trabeculectomy by trabecular meshwork (TM) excision to plasma-mediated ablation in primary open-angle glaucoma (POAG) patients.

Methods

Retrospectively collected data of TrabEx+ (TEx) (n = 56) and Trabectome (T) (n = 99) patients were compared by coarsened exact matching to reduce confounding and matched based on baseline intraocular pressure (IOP) and age. The primary outcomes were IOP and the number of glaucoma medications. Complications and the need for additional glaucoma surgery were assessed. Patients were followed for up to 1 year.

Results

A total of 53 TEx could be matched to T. Baseline IOP was 16.5 ± 4.6 mm Hg in both; age was 73.7 ± 8.8 and 71.5 ± 9.9 years in TEx and T, respectively. TEx was taking more medications than T (p < 0.001). IOP was reduced to 14.8 ± 4.3 in TEx and to 13.4 ± 3.4 in T at 6 months, and to 14.9 ± 6.0 (p = 0.13) in TEx and to 14.1 ± 3.8 mm Hg (all p < 0.05) in T at 12 months. Medications were reduced at both 6 and 12 months (p < 0.05). No differences were seen between TEx and T at 6 and 12 months. In TEx, only one serious complication occurred, and two patients required further glaucoma surgery.

Conclusion

Although both groups had a baseline IOP considered low for ab interno trabeculectomy, IOP and medications were reduced further at 6 and 12 months. IOP reduction did not reach significance in TEx at 12 months. The intergroup comparison did not reveal any significant differences. Both had a low complication rate.

Clinical significance

This study investigated subtle differences between a plasma-ablative device, the T, and an excisional device, the TEx, by applying coarsened exact matching. IOP and medications were reduced in both groups at 6 and 12 months, although IOP reduction did not reach significance in TEx at 12 months. The intergroup comparison did not reveal any significant differences, with both devices having a low complication rate.

How to cite this article

Dakroub M, Verma-Fuehring R, Strzalkowska A, et al. Coarsened Exact Matching of Excisional to Plasma-ablative Ab Interno Trabeculectomy. J Curr Glaucoma Pract 2023;17(1):9-14.

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.

Selective laser trabeculoplasty in steroid-induced and uveitic glaucoma

OBJECTIVE

To compare primary selective laser trabeculoplasty (SLT) response in uveitic, steroid-induced, primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEX).

DESIGN

Single-centre retrospective case-control study.

PARTICIPANTS

Patients with uveitic glaucoma, steroid-induced glaucoma, POAG, or PEX who had their first SLT.

METHODS

Eyes with POAG or PEX were in control groups. Eyes with steroid-induced or uveitic glaucoma were in experimental groups. Change in intraocular pressure from baseline, treatment failure, complication rates, and medication use were compared using rank-sum and log-rank tests.

RESULTS

Six-hundred and eight eyes of 433 patients were enrolled. Steroid-induced glaucoma eyes had higher mean baseline pressure and a decrease in pressure at 3-8 weeks (27.6-17.4 mm Hg) than those with PEX (21.7-16.5 mm Hg; p < 0.001) or POAG (18.6-14.9 mm Hg; p ≤ 0.025). Failure rates after 2 years were lower in steroid-induced glaucoma (54%) than in PEX (84%; p = 0.01) or POAG (84%; p = 0.005). This survival benefit persisted when excluding patients with changes to their steroid dosing (p ≤ 0.03) but showed mixed results when compared with patients with a baseline pressure of 25mm Hg or greater (p = 0.020 vs PEX; p = 0.67 vs POAG). At 18 months, the steroid-induced group decreased ocular hypotensive medication use (3.5-1.9; p = 0.005); the uveitic group increased medication use (2.7-3.5; p = 0.02).

CONCLUSIONS

SLT is an effective treatment for steroid-induced glaucoma, with greater response and a lower failure rate than in PEX and primary POAG, although high baseline intraocular pressure may be a confounder. Judicious use of SLT can be considered in uveitic glaucoma.

Incidence of steroid response in microinvasive glaucoma surgery with trabecular microbypass stent and ab interno trabeculectomy

OBJECTIVE

To determine the incidence and risk factors for steroid response in patients undergoing combined phacoemulsification cataract extraction (PCE) and microinvasive glaucoma surgery with either trabecular microbypass stent implantation (iStent) or ab interno trabeculectomy (Trabectome).

DESIGN

Retrospective, noncomparative, single-institutional observational chart review.

PARTICIPANTS

Consecutive patients with open-angle glaucoma who underwent PCE with iStent or Trabectome with 3 months of follow-up.

METHODS

Data were collected from patient charts, including pre- and postoperative intraocular pressure (IOP) following application of topical corticosteroid on postoperative visits for at least 3 months. A steroid response was defined as an IOP rise of greater than 5 mm Hg beginning at least 3 days after surgery with no other obvious explanation and with IOP < 20 mm Hg following rapid tapering or withdrawal of the steroid.

RESULTS

A total of 118 eyes from 89 patients, average age of 71.4 ±12.1 years, were included. Overall, a steroid response was seen in 12.7% of eyes (n = 15), and no difference was noted between Trabectome (11.8%) and iStent (13.6%, p = 0.782) eyes. Axial length (AL; p = 0.01), younger age (p = 0.009), traumatic glaucoma (p = 0.004), and normal-tension glaucoma (NTG; p = 0.0048) were significant predictors of steroid response in a multivariate analysis. In eyes with AL ≥ 25 mm, the steroid response rate was 40%, in contrast to eyes with AL < 25 mm, where it was 10.2%.

CONCLUSION

A steroid response develops in approximately 1 in 8 patients undergoing PCE with Trabectome or iStent. Young age, AL > 25 mm, traumatic glaucoma, and NTG were found to be significant predictors of steroid response.

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.

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.

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.

Clinical results of ab interno trabeculotomy using the trabectome in patients with uveitic glaucoma

IMPORTANCE

To evaluate the safety and efficacy of ab interno trabeculotomy (AIT) (trabecular ablation) with the trabectome in patients with uveitic glaucoma.

BACKGROUND

Traditional glaucoma filtration surgeries in the uveitic patient population come with a higher risk of complications such as failure and hypotony.

DESIGN

Retrospective observational cohort study.

PARTICIPANTS

All patients diagnosed with uveitic glaucoma were included in this study. Patients were excluded if they have less than 12 months of follow-up.

METHODS

All patients who received AIT alone or combined with phacoemulsification.

MAIN OUTCOME MEASURES

Major outcomes include intraocular pressure (IOP), number of glaucoma medications and secondary glaucoma surgery, if any. Kaplan-Meier method was used for survival analysis and success was defined as IOP ≤21 mmHg, at least 20% IOP reduction from baseline for any two consecutive visits after 3 months, no additional glaucoma medications, and no secondary glaucoma surgery.

RESULTS

A total of 45 eyes, 45 patients, with an average age of 52 years were included in the study. The majority were Japanese (40%) and underwent AIT alone (71%). IOP was reduced from 29.2 ± 8.0 to 16.7 ± 4.6 mmHg at 12 months (P < .01*), while the number of glaucoma medications was reduced from 4.0 ± 1.0 to 2.5 ± 1.6 (P < .01*). Survival rate at 12 months was 91%. Six cases required secondary glaucoma surgery and no other serious complication were reported.

CONCLUSIONS AND RELEVANCE

The trabectome AIT procedure appears to be effective in reducing IOP in uveitic glaucoma patients. Although no statistically significant difference was found in the number of glaucoma medications, a decreasing trend was found.

Gonioscopy-assisted Transluminal Trabeculotomy in a Pediatric Patient With Steroid-induced Glaucoma

PURPOSE

To report a case of successful intraocular pressure (IOP) reduction after a 360-degree gonioscopy-assisted transluminal trabeculotomy (GATT) using the iTrack catheter in a patient with steroid-induced glaucoma as a result of treatment of vernal keratoconjunctivitis (VKC).

MATERIALS AND METHODS

Case report.

RESULTS

An 8-year-old male individual with a long-standing history of VKC, treated with topical steroids, developed elevated IOP and glaucoma in the right eye despite maximum topical glaucoma therapy. Reducing the steroid was not a viable option given the severity of VKC. A 360-degree GATT was successfully performed and IOP has been maintained off all glaucoma drops.

CONCLUSIONS

GATT is a viable option for steroid-induced glaucoma in the pediatric population. This obviates the need for riskier, more invasive conjunctival-based procedures.

Impact of pigment dispersion on trabecular meshwork cells

PURPOSE

Dysfunction of the trabecular meshwork (TM) in pigmentary glaucoma contributes to increased aqueous humor outflow resistance and intraocular pressure. In this study, we investigated the effect of pigment dispersion on trabecular meshwork cells.

METHODS

Porcine TM cells from ab interno trabeculectomy specimens were exposed to pigment dispersion, then, analyzed for changes in morphology, immunostaining, and ultrastructure. Their abilities to phagocytose migrate, and contraction was quantified. An expression microarray, using 23,937 probes, and a pathway analysis were performed.

RESULTS

Stress fiber formation was increased in the pigment dispersion group (P) (60.1 ± 0.3%, n = 10) compared to control (C) (38.4 ± 2.5%, n = 11, p < 0.001). Phagocytosis declined (number of cells with microspheres in P = 37.0 ± 1.1% and in C = 68.7 ± 1.3%, n = 3, p < 0.001) and migration was reduced after 6 h (cells within the visual field over 6 h in P = 28.0.1 ± 2.3 (n = 12) and in C = 40.6 ± 3.3 (n = 13), p < 0.01). Pigment induced contraction at 24 h onwards (p < 0.01). Microarray analysis revealed that Rho signaling was central to these responses.

CONCLUSION

Exposure of TM cells to pigment dispersion resulted in reduced phagocytosis and migration, as well as increased stress fiber formation and cell contraction. The Rho signaling pathway played a central and early role, suggesting that its inhibitors could be used as a specific intervention in treatment of pigmentary glaucoma.

RKI-1447, a Rho kinase inhibitor, causes ocular hypotension, actin stress fiber disruption, and increased phagocytosis

PURPOSE

This study investigated the hypotensive effect of RKI-1447, a Rho kinase inhibitor, in a porcine ex vivo pigmentary glaucoma model.

METHODS

Twenty-eight porcine anterior chambers were perfused with medium supplemented with 1.67 × 10⁷ pigment particles/ml for 48 h before treatment with RKI-1447 (n = 16) or vehicle control (n = 12). Intraocular pressure (IOP) was recorded and outflow facility was calculated. Primary trabecular meshwork cells were exposed to RKI-1447 or vehicle control; effects on the cytoskeleton, motility, and phagocytosis were evaluated.

RESULT

Compared to baseline, the perfusion of pigment caused a significant increase in IOP in the RKI-1447 group (P = 0.003) at 48 h. Subsequent treatment with RKI-1447 significantly reduced IOP from 20.14 ± 2.59 to 13.38 ± 0.91 mmHg (P = 0.02). Pigment perfusion reduced the outflow facility from 0.27 ± 0.03 at baseline to 0.18 ± 0.02 at 48 h (P < 0.001). This was partially reversed with RKI-1447. RKI-1447 caused no apparent histological changes in the micro- or macroscopic TM appearance. RKI-1447-treated primary TM cells showed significant disruption of the actin cytoskeleton both in the presence and absence of pigment (P < 0.001) but no effect on TM migration was observed. Pigment-treated TM cells exhibited a reduction in TM phagocytosis, which RKI-1447 reversed.

CONCLUSION

RKI-1447 significantly reduces IOP by disrupting TM stress fibers and increasing TM phagocytosis. These features may make it useful for the treatment of secondary glaucomas with an increased phagocytic load.

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.

Two-year outcomes of ab interno trabeculectomy with the Trabectome for Chinese primary open angle glaucoma: a retrospective multicenter study

AIM

To evaluate the 2-year efficacy and safety of ab interno trabeculectomy with the Trabectome in Chinese primary open angle glaucoma (POAG) patients.

METHODS

This was a multicenter, retrospective, observational study and included POAG patients with or without visually-significant cataracts. The Chinese patients were enrolled from three glaucoma centers and a group of comparable Japanese POAG patients was analyzed from our international Trabectome database. The patients received Trabectome or a combined surgery with phacoemulsification and intraocular lens implantation. The primary outcome was intraocular pressure (IOP) reduction. Secondary outcomes included reduction of glaucoma medications, surgical complications, and success at 2y. Success was defined as: 1) IOP≤21 mm Hg and at least 20% IOP reduction from baseline after 3mo at any two consecutive visits; 2) no additional glaucoma surgery required.

RESULTS

A total of 42 Chinese POAG patients from three glaucoma centers were enrolled. Twelve patients underwent Trabectome surgery combined with phacoemulsification and intraocular lens implantation while the remainder underwent Trabectome surgery alone. Thirteen patients had a history of failed glaucoma surgery and were considered as complicated cases. In China data, the mean preoperative IOP was 21.4±1.23 mm Hg. The Trabectome lowered IOP to 17.9±1.8 mm Hg at 2y (P=0.05). The number of glaucoma medications also decreased significantly from a baseline of 2.0±0.9 to 1.1±0.8 at 2y post-surgery (P=0.04). The overall 2-year success rate was 78%, with patients undergoing combined surgery having a higher success rate compared with those undergoing Trabectome surgery alone (100% vs 76%). In Japan data, the mean preoperative IOP was 20.8±7.7 mm Hg. The Trabectome lowered IOP to 12.20±2.0 mm Hg at 2y. The number of glaucoma medications also decreased significantly from a baseline of 2.1±0.9 to 3.4±0.6 at 2y post-surgery. In all patients, no major complications were seen.

CONCLUSION

Surgery with the Trabectome appears to be an efficient and safe procedure in Chinese POAG patients in the long-term.

Outcome of Primary Nonpenetrating Deep Sclerectomy in Patients with Steroid-Induced Glaucoma

Purpose

To evaluate the outcome of primary nonpenetrating deep sclerectomy (NPDS) in patients with steroid-induced glaucoma.

Methods

This was a retrospective interventional clinical study that included 60 eyes of 60 steroid-induced glaucoma patients that had undergone NPDS. Patients were followed up for 4 years. Data from the records was retrieved as regards corrected distance visual acuity (CDVA), intraocular pressure (IOP), visual field mean defect (dB), and number of antiglaucoma medications needed if any. Complete success of the surgical outcome was considered an IOP ≤ 21 mmHg with no antiglaucoma medications. Qualified success was considered an IOP ≤ 21 mmHg using antiglaucoma medications.

Results

The mean age was 21.2 ± 8.5 years (ranged from 12 to 35 years). At 48 months, mean IOP was 13.6 ± 2.8 mmHg (range 11-23 mmHg). This represented 60% reduction of mean IOP from preoperative levels. One case had YAG laser goniopuncture. Three cases required needling followed by ab interno revision. Using ANOVA test, there was a statistically significant difference between preoperative and postoperative mean IOP values (P = 0.032). Twelve, 16, and 20 patients required topical antiglaucoma medications at 24, 26, and 48 months postoperative, respectively.

Conclusion

Primary nonpenetrating deep sclerectomy is a safe and an effective method of treating eyes with steroid-induced glaucoma. No major complications were encountered. After 4 years of follow-up, complete success rate was 56.7% and qualified success rate was 70%.

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.

A porcine ex vivo model of pigmentary glaucoma

Pigment dispersion can lead to pigmentary glaucoma, a poorly understood condition of younger myopic eyes with fluctuating high intraocular pressure. It has been difficult to investigate its pathogenesis without a model similar to human eyes in size and behavior. Here we present a porcine ex vivo model that recreates several features of pigmentary glaucoma, including intraocular hypertension, accumulation of pigment in the trabecular meshwork, and declining phagocytosis. We found that trabecular meshwork cells regulate outflow, form actin stress fibers, and have a decreased phagocytic activity. Gene expression microarrays and a pathway analysis of TM monolayers as well as ex vivo anterior segment perfusion cultures indicated that RhoA plays a central role in regulating the cytoskeleton, motility, and phagocytosis in the trabecular meshwork, providing new insights and targets to investigate in pigmentary glaucoma.

Impact of same-session trabectome surgery on Ahmed glaucoma valve outcomes

PURPOSE

To evaluate the efficacy and survival rates of same session ab interno trabeculectomy with the trabectome and Ahmed glaucoma valve implant (AT) in comparison to the Ahmed glaucoma valve alone (A).

METHOD

A total of 107 eyes undergoing primary glaucoma surgery were enrolled in this retrospective comparative case series, including 48 eyes which underwent AT and 59 eyes which received A alone. Participants were identified using the procedural terminology codes, and their medical records were reviewed. The primary outcome measure was success defined as IOP > 5 mmHg, ≤ 21 mmHg and ≥ 20% reduction of IOP from baseline at two consecutive visits after 3 months, and no need for glaucoma reoperation. Secondary outcome measures were IOP, the number of glaucoma medications, incidence of a hypertensive phase, and best corrected visual acuity (BCVA).

RESULTS

The cumulative probability of success at 1 year was 70% in AT, and 65% in A (p = 0.85). IOP decreased significantly from 26.6 ± 10.1 mmHg at baseline to 14.7 ± 3.3 mmHg at the final follow-up in AT (p = 0.001). The corresponding numbers for A were 27.8 ± 10.2 and 16.7 ± 4.9, respectively (p = 0.001). The final IOP was significantly lower in AT (p = 0.022). The number of medications at baseline was comparable in both groups (2.6 ± 1.2 in AT and 2.5 ± 1.3 in A, p = 0.851). Corresponding number at 1 year visit was 1.2 ± 2 in AT and 2.8 ± 1.8 in A (p = 0.001). The incidence of a hypertensive phase was 18.7% in AT and 35.5% in A (p = 0.05). HP resolved in only 30% of eyes. The criteria for HP resolution were fulfilled in 9 eyes (30%). There was no difference in the rate of resolution of the hypertensive phase between AT and A (33.3 and 28.5%, respectively, p = 0.67).

CONCLUSION

Ahmed glaucoma valve implant with same session trabectome surgery significantly decreased the rate of the hypertensive phase and postoperative IOP as well as the number of glaucoma medications.

Safety and Efficiency of Trabectome-mediated Trabecular Meshwork Ablation for Chinese Glaucoma Patients: A Two-year, Retrospective, Multicentre Study

BACKGROUND

The aim of the study was to evaluate the long-term safety and efficacy of the Trabectome for Chinese glaucoma patients.

METHODS

This was a multicenter, retrospective, observational study. Glaucoma patients, except those with neovascular glaucoma, with/without a visually significant cataract were enrolled. The patients received Trabectome or a combined surgery with phacoemulsification and intraocular lens implantation. The primary outcome evaluation was a reduction in intraocular pressure (IOP), and the secondary outcomes were a reduction in glaucoma medication, the 2-year success percentages, and complications. Success was defined as an IOP <21 mmHg and at least a 20% IOP reduction from baseline after 3 months for any two consecutive visits, without additional glaucoma surgery. The data were processed using the R Stats Package version 3.0.0. The Wilcoxon test was used to compare the postoperative IOP and the number of glaucoma medications with baselines. The Kaplan-Meier test was used to calculate the 2-year success percentage. The risk factors related to Trabectome failure were determined by logistic regression.

RESULTS

A total of 120 glaucoma patients were enrolled. The Trabectome efficiently reduced the IOP from a baseline of 22.8 ± 1.34 mmHg to 17.6 ± 0.96 mmHg, and the use of glaucoma medications from 2.2 ± 0.17 mmHg to 1.4 ± 0.21 in a 2-year follow-up (both, P < 0.01). The overall success percentage was 80%. No risk factor related to Trabectome failure was identified. No vision-threatening complication was observed. Ten patients, who required secondary glaucoma surgery, all reached the target IOP.

CONCLUSIONS

In a 2-year follow-up, Trabectome was an efficient and safe procedure for Chinese glaucoma patients.

Canaloplasty in Corticosteroid-Induced Glaucoma. Preliminary Results

PURPOSE

to present the mid-term results of canaloplasty in a small cohort of corticosteroid glaucoma patients.

MATERIAL AND METHODS

Nine eyes from seven patients with various types of corticosteroid glaucoma in maximum medical therapy underwent canaloplasty. Patients underwent complete ophthalmic examination every six months. Success was defined as: post-operative intraocular pressure (IOP) ≤ 21 mmHg and ≤ 16 mmHg without ("complete success"), and with/without medical treatment ("qualified success"). The IOP reduction had to be ≥ 20. The number of medications before and after surgery was considered. The follow-up mean period was 32.7 ± 20.8 months (range 14-72 months).

RESULTS

The pre-operative mean IOP was 30.7 ± 7.2 mmHg (range: 24-45). The mean IOP at 6 and 12-month follow-up was 13.1 ± 2.6 mmHg, and 13.7 ± 1.9 mmHg, respectively. Qualified and complete success at 6 and 12 months was 100% for both of the two definitions. The number of medications used preoperatively and at the 12-month follow-up was 4.3 ± 0.7, and 0.2 ± 1.0, respectively. No serious complication was observed.

CONCLUSIONS

The mid-term results of canaloplasty in patients with corticosteroid-induced glaucoma appear to be very promising. Canaloplasty should be considered as a possible alternative to filtering surgery in this form of glaucoma, when medical therapy is not sufficient to maintain the IOP within reasonable limits.

Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy

Background: To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP) on the success rate of trabeculectomy.

Methods: In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS). Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC).

Results: The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911). IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively.) The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971) with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91%) and a specificity of 87.5% (95% CI: 53 to 98%).

Conclusions: IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy.  An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.

Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy

Background: To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP) on the success rate of trabeculectomy. Methods: In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS). Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC). Results: The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911). IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively.) The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971) with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91%) and a specificity of 87.5% (95% CI: 53 to 98%). Conclusions: IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy.  An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.

Trabeculotomy ab interno with Trabectome as surgical management for systemic fluoroquinolone-induced pigmentary glaucoma: A case report

RATIONALE

Bilateral acute iris transillumination (BAIT) is a poorly-understood ocular syndrome in which patients present with acute iridocyclitis and pigmentary dispersion with or without ocular hypertension. The etiology of the disease remains unknown, though recent reports suggest an antecedent upper respiratory tract infection or systemic antibiotic administration may trigger the clinical syndrome.

PATIENT CONCERNS

A 55-year-old female was referred for a second opinion regarding her bilateral ocular pain, photophobia, and ocular hypertension. Her medical history was notable for a diagnosis of pneumonia managed with oral moxifloxacin several weeks prior to her initial presentation.

DIAGNOSES

Visual acuity was 20/40 with an intraocular pressure (IOP) of 30 mmHg in the affected eye despite maximal tolerated medical therapy. The patient had severe bilateral iris transillumination defects with posterior synechiae formation and 3+ pigment with rare cell in the anterior chamber. This constellation of findings was consistent with a diagnosis of BAIT.

INTERVENTIONS

A peripheral iridotomy was placed, which mildly relieved the iris bowing, but did not affect the IOP or inflammatory reaction. The patient then underwent cataract extraction with posterior synechiolysis and ab interno trabeculotomy of the left eye with the Trabectome.

OUTCOMES

The patient's IOP on the first post-operative day was 13 mmHg, and anterior chamber inflammation was noted to be significantly reduced at post-operative week 2. The patient was recently seen at a 1-year post-operative visit and her IOP remains in the low teens on a low-dose combination topical agent.

LESSONS

Ophthalmologists should remain aware of the association between systemic fluoroquinolones and acute pigmentary dispersion that can progress to glaucoma. The Trabectome remains a viable option for management of pigmentary and uveitic glaucoma resistant to medical treatment.

Freeze-thaw decellularization of the trabecular meshwork in an ex vivo eye perfusion model

Objective

The trabecular meshwork (TM) is the primary substrate of outflow resistance in glaucomatous eyes. Repopulating diseased TM with fresh, functional TM cells might be a viable therapeutic approach. Decellularized TM scaffolds have previously been produced by ablating cells with suicide gene therapy or saponin, which risks incomplete cell removal or dissolution of the extracellular matrix, respectively. We hypothesized that improved trabecular meshwork cell ablation would result from freeze-thaw cycles compared to chemical treatment.

Materials and Methods

We obtained 24 porcine eyes from a local abattoir, dissected and mounted them in an anterior segment perfusion within two hours of sacrifice. Intraocular pressure (IOP) was recorded continuously by a pressure transducer system. After 72 h of IOP stabilization, eight eyes were assigned to freeze-thaw (F) ablation (−80 °C × 2), to 0.02% saponin (S) treatment, or the control group (C), respectively. The TM was transduced with an eGFP expressing feline immunodeficiency viral (FIV) vector and tracked via fluorescent microscopy to confirm ablation. Following treatment, the eyes were perfused with standard tissue culture media for 180 h. TM histology was assessed by hematoxylin and eosin staining. TM viability was evaluated by a calcein AM/propidium iodide (PI) assay. The TM extracellular matrix was stained with Picro Sirius Red. We measured IOP and modeled it with a linear mixed effects model using a B-spline function of time with five degrees of freedom.

Results

F and S experienced a similar IOP reduction of 30% from baseline (P = 0.64). IOP reduction of about 30% occurred in F within 24 h and in S within 48 h. Live visualization of eGFP demonstrated that F conferred a complete ablation of all TM cells and only a partial ablation in S. Histological analysis and Picro Sirius staining confirmed that no TM cells survived in F while the extracellular matrix remained. The viability assay showed very low PI and no calcein staining in F in contrast to many PI-labeled, dead TM cells and calcein-labeled viable TM cells in S.

Conclusion

We developed a rapid TM ablation method that uses cyclic freezing that is free of biological or chemical agents and able to produce a decellularized TM scaffold with preserved TM extracellular matrix in an organotypic perfusion culture.

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.

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.