Six-Month Outcomes of Goniotomy Performed with the Kahook Dual Blade as a Stand-Alone Glaucoma Procedure

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.

Trabeculotomy Using the Kahook Dual Blade for Exfoliation Glaucoma and Primary Open Angle Glaucoma: Comparison of Outcomes According to Incision Range

PRCIS

Large amount of trabeculotomy with Kahook Dual Blade (KDB) confers better intraocular pressure (IOP) lowering.

PURPOSE

We compared the postoperative outcomes of trabeculotomy using the KDB in patients with exfoliation glaucoma (EXG) and primary open angle glaucoma between the 120-degree incision and the 210- to 240-degree incision groups.

PATIENTS AND METHODS

We retrospectively analyzed the postoperative outcomes of trabeculotomy performed using the KDB in 101 eyes with EXG and primary open angle glaucoma, who received 120- and 210- to 240-degree incisions at Kumamoto University Hospital between April 25, 2018, and August 11, 2021. Kaplan-Meyer survival curves were used to assess the outcomes. Surgical failure was defined as IOP ≥21 mm Hg (criterion A) and ≥19 mm Hg (criterion B), or an IOP ≤4 mm Hg in either criterion and the need for additional glaucoma surgery.

RESULTS

In total, 64 and 37 eyes were included in the 120 and 210- to 240-degree groups, respectively. The 210- to 240-degree group had a higher 1-year success rate compared with the 120-degree group, both when considering all eyes and when considering only those with EXG (P<0.05).

CONCLUSIONS

In trabeculotomy with KDB, a 210- to 240-degree incision was more effective than a 120-degree incision in lowering IOP in EXG cases.

Twelve-month outcomes of Kahook dual blade goniotomy combined with cataract surgery in Latino patients

PURPOSE

To evaluate 12 month surgical outcome of Kahook Dual Blade (KDB) goniotomy in combination with cataract surgery in Latino patients with open angle glaucoma (OAG) and ocular hypertension (OHT).

METHODS

This retrospective study included 45 eyes of 40 patients who underwent KDB goniotomy combined with cataract extraction from January 2016 to September 2020 at two centers in South America. Primary outcome was surgical success defined as ≥ 20% intraocular pressure (IOP) reduction or ≥ 1 medication reduction from preoperative without additional IOP-lowering procedures and an IOP ≥ 5 mmHg or ≤ 21 mmHg. Additionally, we used 2 cutoffs values for success of IOP ≤ 18 and ≤ 15 mmHg. Secondary outcomes included: IOP, medication use, best corrected visual acuity, complications and failure-associated factors.

RESULTS

Success rates at 12 months with cutoff limits of 21, 18 and 15 mmHg were 84.3%, 75.6% and 58.7%, respectively. At 12 months, mean preoperative IOP significantly decreased from 19.23 ± 0.65 mmHg on 2.3 ± 1.0 medications to 14.33 ± 0.66 mmHg on 0.6 ± 0.9 medications (p < 0.001) , with 62% of eyes free of hypotensive medication. Eyes that developed postoperative IOP spikes showed a higher risk for failure using the cutoff limit of IOP ≤ 18 mmHg with a hazard ratio of 3.6 (95% confidence interval [CI], 1.80-7.13; p < 0.001). There were no serious ocular adverse events.

CONCLUSIONS

KDB combined with cataract extraction showed safety and efficacy for decreasing IOP in OAG and OHT Latino patients. Additionally, dependence on medications was reduced significantly after surgery.

Which is More Effective and Safer? Comparison of Propensity Score-Matched Microhook Ab Interno Trabeculotomy and iStent Inject

INTRODUCTION

The purpose of this study was to compare the surgical outcomes between ab interno trabeculotomy (LOT) and iStent inject W implantation (iStent) both combined with cataract surgery, matching the background factors including age, intraocular pressure (IOP), medication score, central corneal thickness (CCT), and axial length.

METHODS

A total of 100 eyes from 75/79 patients with primary open-angle glaucoma were included in the LOT/iStent groups. The background factors were matched between the two groups using the propensity score.

RESULTS

There were no significant differences in age, IOP, medication score, CCT, and axial length, preoperatively. The postoperative medication scores were 1.3 ± 1.2 and 1.2 ± 1.2 in the LOT and iStent groups. The postoperative IOPs were 12.8 ± 2.8 and 13.1 ± 2.4 mmHg in the LOT and iStent groups, respectively. The changes in the medication score were  - 0.64 ± 1.4 and  - 0.44 ± 1.6 in the LOT and iStent groups, respectively. The changes in the IOP were  - 2.1 ± 3.3 and  - 1.5 ± 3.0 mmHg in the LOT and iStent groups, respectively. These values were not significantly different between the two groups. The postoperative IOP and changes in the IOP were significantly associated with preoperative IOP and CCT. There was no significant difference in the occurrence of postoperative complications (hyphema, 11.0% and 6.0%, and transient ocular hypertension, 8.0% and 5.0%, in the LOT and iStent groups, respectively).

CONCLUSION

LOT and iStent have similar surgical outcomes with sufficient safety. Postoperative IOP was significantly associated with preoperative IOP and CCT in both groups.

Postoperative Management of Kahook Dual Blade Goniotomy with Phacoemulsification Cataract Extraction

Aim

To review the efficacy and safety of two common postoperative regimens following Kahook Dual Blade goniotomy with phacoemulsification cataract extraction (KDB-CE).

Materials and methods

This is a retrospective review of eyes undergoing KDB-CE from May 2016 to 2018 by a single surgeon. Almost 12-month follow-up data were assessed for two common postop regimens-treatment with (1) topical prednisolone acetate 1% with pilocarpine 1% (pred-pilo) or (2) difluprednate 0.05% postoperatively. Postoperative results were compared to each respective baseline intraocular pressure (IOP) levels.

Results

There were 53 eyes in the difluprednate group and 25 eyes in the pred-pilo group. In the difluprednate group, the IOP decreased at postoperative day 1 (POD1) [16 ± 5 baseline vs 15 ± 5 POD1, mean ± standard deviation (SD) in mm Hg, and p = 0.321], but increased at postoperative week 1 (POW1) due to a 15% rate of IOP-spikes (19 ± 9, p = 0.099). The number of IOP-lowering drops decreased from baseline (2 ± 1 drops) to 1 ± 1 drops at POD1 (p < 0.0001), and remained at 1 ± 1 drops through postoperative month 12 (POM12) (p < 0.0001). In the pred-pilo group, there was a statistically significant decrease in mean IOP at POW1 (16 ± 4 POW1 vs 18 ± 6 baseline, p = 0.044), which persisted through POM6. The number of IOP-lowering drops was not statistically significantly lower from baseline at POM3 (2 ± 1 at POM3, p = 0.188). Spikes in IOP, corneal edema, and hyphema were the most common complications.

Conclusion

Both postoperative regimens were effective following KDB-CE at reducing IOP at 12 months. The difluprednate group was likely to experience an IOP-spike at POW1 but used fewer IOP-lowering drops 12 months after KDB goniotomy. In the pred-pilo group, the number of IOP-lowering drops was equivalent to baseline levels at POM3. Aside from IOP spikes, there were similar complication rates observed between the two postoperative regimens. Due to demographic differences, it was not possible to compare relative IOP-lowering efficacy between the two postoperative regimens.

Clinical significance

It is efficacious and safe to use either postoperative regimen following KBD-CE. Postoperative trajectories may differ with respect to the postoperative regimen, but further randomized controlled trials are needed to compare various topical steroid medications for postoperative regimens following KDB-CE.

How to cite this article

Birnbaum F, Wakil S, Vu DM, et al. Postoperative Management of Kahook Dual Blade Goniotomy with Phacoemulsification Cataract Extraction. J Curr Glaucoma Pract 2023;17(4):169-174.

Minimally Invasive Glaucoma Surgery: A Review of the Literature

Minimally invasive glaucoma surgery (MIGS) has emerged as a novel approach in the glaucoma treatment spectrum, offering a range of diverse procedures and devices aimed at reducing intraocular pressure (IOP). MIGS can be broadly classified into several categories: those that enhance trabecular outflow (Trabectome, iStent, Hydrus Microstent, Kahook Dual Blade, high frequency deep sclerotomy, and gonioscopy-assisted transluminal trabeculotomy), those that augment suprachoroidal outflow (CyPass Microstent and iStent Supra), those that target Schlemm's canal (TRAB360 and the OMNI Surgical System, Streamline, and Ab Interno Canaloplasty), and conjunctival bleb-forming procedures (EX-PRESS Glaucoma Filtration Device, Xen Gel Stent and PreserFlo MicroShunt). MIGS is considered to have a shorter surgical time and fewer severe complications when compared to traditional glaucoma surgeries such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves). This literature review comprehensively examines the distinct MIGS devices and procedures, their underlying mechanisms, and clinical outcomes, emphasizing the importance of evaluating the efficacy and complications of each approach individually. As the field of MIGS continues to evolve, it is crucial to prioritize high-quality, long-term studies to better understand the safety and effectiveness of these innovative interventions in glaucoma management.

[Ab interno trabeculotomy without/with cataract operation-An alternative treatment before or instead of trabeculectomy in patients with high intraocular pressure?]

BACKGROUND

Trabeculotomy with the Kahook knife is a new ab interno minimally invasive glaucoma surgery (MIGS) procedure. The MIGS are usually performed in early to intermediate glaucoma eyes. In this retrospective study we analyzed the intraocular pressure (IOP) and topical glaucoma eye drop therapy (Meds) reduction achieved by the Kahook trabeculotomy (TO) without (n = 19) or with (n = 18) combined cataract operation (Cat-TO) as initial treatment before or to avoid filtering surgery.

MATERIAL AND METHODS

A total of 37 eyes of 37 patients were examined when IOP was > 21 mm Hg in at least 2 examinations despite the maximum tolerable Meds applied. Cat-TO was performed in 18 phakic eyes (primary open-angle glaucoma, POAG = 11, pseudoexfoliation glaucoma, PEX = 5, ocular hypertension, OHT = 2). In 19 pseudophakic eyes (POAG = 12, PEX = 6, OHT = 1) an isolated TO was executed. Complete success (no Meds) and relative success (irrespective of Meds) for IOP ≤ 21 mm Hg, ≤ 18 mm Hg, ≤ 16 mm Hg were evaluated 2, 6 and 12 months postoperatively.

RESULTS

The IOP was significantly reduced from preoperatively to 2 months after Cat-TO as well as after TO (Cat-TO: 26.8 ± 5.9 mm Hg to 16.0 ± 2.9 mm Hg, p < 0.001; TO: IOD 28.2 ± 5.6 mm Hg to 16.3 ± 3.5 mm Hg, p < 0.001). Meds reduction after Cat-TO as well as after TO was not significant (Cat-TO: 2.1 ± 1.3 to 1.3 ± 1.3, p = 0.11; TO: Meds 2.7 ± 1.1 to 2.2 ± 1.3, p = 0.23); however, Meds reduction after 6 and 12 months was significantly greater in the Cat-TO group compared to the TO group (p = 0.02). The IOP and Meds did not change significantly from 2 to 6 months. After Cat-TO, qualified success after 12 months for IOP ≤ 18 mm Hg was 61% (11/18) and for IOP ≤ 16 mm Hg 28% (5/18). After TO, qualified success after 12 months for TO was 47% (9/19) for IOP ≤ 18 mm Hg and 26% (5/19) for IOP ≤ 16 mm Hg. The intervention was not sufficient for 7 patients after TO and 2 patients after Cat-TO (IOP two times > 21 mm Hg).

CONCLUSION

The first year results show that TO as well as Cat-TO are effective minimally invasive interventions to delay or even avoid a filtrating operation. In case of Meds intolerance and target IOP ≤ 16 mm Hg Cat-TO is not sufficient.

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.

The case for standalone micro-invasive glaucoma surgery: rethinking the role of surgery in the glaucoma treatment paradigm

PURPOSE OF REVIEW

To highlight progress in glaucoma therapy challenging the traditional medication-first approach and present evidence supporting early standalone surgery in the era of micro-invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Medical therapy is limited by well documented poor adherence that compromises the quality of intraocular pressure reduction. Results from modern clinical trials demonstrate advantages of selective laser trabeculoplasty and MIGS procedures in terms of both IOP control and progression risk.

SUMMARY

The MIGS options for pseudophakic or precataractous patients are limited by regulatory rules that require the performance of some procedures only at the time of cataract surgery. These include the iStent/iStent Inject and the Hydrus implants. Nonbleb-forming procedures currently available for standalone use in eyes with mild-moderate primary open-angle glaucoma include gonioscopy-assisted transluminal trabeculotomy (which lowers IOP by 28-61% and medication use by 38-73% in various studies), trabecular ablation with the Trabectome (23-39% and 21-43%, respectively), excisional goniotomy with the Kahook Dual Blade (15-36% and 15-40%, respectively), ab interno canaloplasty (35% and 57%, respectively), and combined canaloplasty and trabeculotomy using the OMNI system (39-40% and 64-73%, respectively). For patients who would benefit from early standalone surgery, these procedures offer meaningful reductions in both IOP and medication burden.

Combined Microinvasive Glaucoma Surgery - A Review of the Literature and Future Directions

The use of microinvasive invasive glaucoma surgery (MIGS) in the treatment of glaucoma has increased exponentially over the last 10 years. However, practice patterns vary widely given the relative newness of these technologies. Some surgeons perform two or more MIGS simultaneously, such as those that target aqueous production and those that target aqueous outflow. These combined MIGS (cMIGS) may result in lower intraocular pressure (IOP) and reduced medication burden as compared to single MIGS (sMIGS). Current evidence suggests some cMIGS are more effective in reducing medication burden for at least 12 months versus sMIGS. This review focuses on the current evidence related to the efficacy of cMIGS as well as novel combinations of standalone MIGS, limitations of the current literature, and future directions for research.

Outcomes and risk factors for ab interno trabeculotomy with a Kahook Dual Blade

PURPOSE

To verify the surgical results and risk factors for ab interno trabeculotomy using a Kahook Dual Blade (KDB-LOT) in patients with various glaucoma types.

METHODS

This study was a retrospective case series of 205 eyes that underwent KDB-LOT. For Kaplan-Meier survival analysis, criterion A was defined as a ≤ 20% reduction in intraocular pressure (IOP) from baseline. Criteria B, C, and D were IOPs of ≤ 21, 18, and 15 mmHg, respectively. The Cox proportional hazard (CPH) model investigated prognostic factors.

RESULTS

The mean (SD) IOP decreased from 24.7 (7.98) to 17.6 (4.80) mmHg in all cases, from 21.3 (6.88) to 17.8 (3.52) mmHg in primary open-angle glaucoma (POAG), from 25.4 (7.32) to 17.1 (4.65) mmHg in exfoliation glaucoma, from 30.6 (8.88) to 17.8 (8.29) mmHg in uveitic glaucoma, and from 30.8 (7.29) to 17.3 (0.83) mmHg in steroid-induced glaucoma at 1 year after KDB-LOT. The Kaplan-Meier survival analysis showed that patients with POAG had the best prognosis under criteria B and C, and the 1-year survival rate in patients under criterion D was less than 35% for any disease type. CPH analysis revealed that age and KDB-LOT with phacoemulsification were good prognostic factors. Risk factors for surgical failure were previous cataract surgery, selective laser trabeculoplasty, and postoperative peripheral anterior synechiae.

CONCLUSION

KDB-LOT was effective in treating patients with several glaucoma types but showed difficulty in pushing IOP below 15 mmHg. Prognostic factors should be considered when making decisions regarding surgical indications.

Risk factors of surgical failure in combined phacoemulsification and excisional goniotomy for angle-closure glaucoma

PURPOSE

To evaluate the therapeutic success, and risk factors for combined phacoemulsification and Kahook Dual Blade excisional goniotomy (Phaco/KDB) in primary angle-closure glaucoma (PACG).

METHODS

A retrospective review was conducted on glaucoma patients who underwent Phaco/KDB between September 2019 and August 2021 at 2 ophthalmology centers. Complete success was defined as unmedicated intraocular pressure (IOP) ≤ 18 mmHg with no further glaucoma surgery, while the medicated IOP ≤ 18 mmHg was defined as qualified success with lesser medications than at baseline.

RESULTS

Seventy-two eyes (64 patients) with a mean age of 67.1 ± 8.1 years were included in this study, and 70.2% were female. The mean medicated baseline IOP decreased from 23.4 ± 8.1 to 16.6 ± 3.9 mmHg at an average of 11.6 ± 3.7 months of follow-up (- 29.1%; P < 0.00). Medications decreased from 2.6 ± 1.3 to 0.4 ± 0.9 (- 82.6%; P < 0.001). Complete success and qualified success were achieved in 65.3% and 79.2% of eyes, respectively. Male gender [hazard ratio (HR): 6.00 (1.57-22.9); P = 0.009] was observed a risk factor for surgical failure, whereas higher axial length (HR:0.37 (0.16-0.86); P = 0.021), and a combined circumferential goniosynechialysis procedure (HR: 0.13 (0.02-0.74); P = 0.022) lowered the risk of surgical failure. Hyphema, postoperative shallowing anterior chamber, and IOP spike were the most common complications. The cumulative survival proportion for qualified success at 12 months was 82.5% ± 0.05 (95% CI, 0.70-0.90).

CONCLUSION

Phaco/KDB provided acceptable therapeutic success rate and may, therefore, be recommended in patients with coexisting cataract and PACG. Identifying patients with risk factors preoperatively may help clinicians predict surgical success.

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.

Kahook Dual-Blade Goniotomy with and without Phacoemulsification in Medically Uncontrolled Glaucoma

Purpose

To evaluate the 2-year efficacy and safety of Kahook dual-blade (KDB) goniotomy in patients with medically uncontrolled glaucoma.

Methods

This was a retrospective case-series study of 90 consecutive patients with primary open-angle glaucoma (POAG) or pseudoexfoliation glaucoma (PEXG) that underwent KDB goniotomy alone (KDB-alone group) or KDB goniotomy in combination with phacoemulsification (KDB-phaco group) during 2019-2020. All patients were uncontrolled on three or more medications. Surgical success was defined as an IOP reduction ≥20% and/or a reduction of one or more medications at 24 months. We also report IOP levels and number of medications from baseline to 24 months, as well as the need for further glaucoma interventions.

Results

At 24 months, mean IOP had reduced from 24.8±8.3 to 15.0±5.3 mmHg in the KDB-alone group (P<0.001) and from 22.3±5.8 to 13.9±3.0 mmHg in the KDB-phaco group (P<0.001). Medications had reduced from 3.5±0.6 to 3.1±0.9 in the KDB-alone group (P=0.047) and from 3.3±0.5 to 2.3±1.1 in the KDB-phaco group (P<0.001). An IOP reduction ≥20% and/or a reduction with one or more medications was achieved by 47% of eyes in the KDB-alone group and by 76% of eyes in the KDB-phaco group. Eyes with PEXG and POAG responded equally well to the success criteria. During the 24-month follow-up, additional glaucoma surgery or transscleral photocoagulation was performed in 28% of eyes in the KDB-alone group and in 12% of eyes in the KDB-phaco group.

Conclusion

In patients with medically uncontrolled glaucoma, KDB had a significant IOP-lowering effect after 24 months, but success rates were higher when KDB was performed in combination with cataract surgery compared to stand-alone treatment.

Minimally Invasive Glaucoma Surgery: Safety of Individual Devices

Primary open-angle glaucoma progression in those already on maximal medical therapy has traditionally been treated with trabeculectomy, a surgical procedure that carries a high degree of morbidity. In the last few decades, significant advances have been made in the field of minimally invasive glaucoma surgery (MIGS) devices, which aim to defer or prevent trabeculectomy via less arduous surgical techniques in certain types of glaucoma. Although reviews have been published examining the efficacy of various MIGS techniques, no article synthesises the comparative safety of all available devices. We performed a literature review examining the safety of MIGS devices. Fifteen devices were included, variously attempting to increase aqueous outflow through the trabecular meshwork or the suprachoroidal space, shunting into the subconjunctival space, or reducing aqueous production through ciliary body ablation. Notably, the earliest product attempting to increase outflow to the suprachoroidal space, Alcon's CyPass Micro-Stent, was withdrawn from the market due to concerns regarding increased corneal endothelial cell loss at five years post-implantation. All other devices were described as well-tolerated, with the most common adverse effects including hyphaema, intraocular pressure spikes, and device migration or obstruction. MIGS devices are purported to be uniformly safe, and many studies report no statistically significant increased complications beyond those associated with cataract surgery alone. It is important to note, however, the generally poor quality of current studies, with a dearth of randomised, or even prospective, data, and a large proportion of studies funded by device producers.

Stand-Alone Xen Gel Microstent Implantation Compared With Kahook Dual Blade Goniotomy

PRCIS

Both Xen gel Microstent implantation and Kahook Dual Blade (KDB) goniotomy are safe and effective as stand-alone procedures, but the Xen Gel Microstent was associated with more postoperative interventions and achieved higher success at a lower intraocular pressure threshold.

PURPOSE

To evaluate outcomes of stand-alone Xen Gel Microstent implantation compared with stand-alone KDB goniotomy for moderate to severe glaucoma.

METHODS

A retrospective, single-center, case-series analysis comparing outcomes of Xen Gel Microstent implantation and KDB goniotomy stand-alone cases in 75 eyes. Primary outcomes included intraocular pressure (IOP) reduction, glaucoma medication reduction, surgical success, and complications. Surgical success was defined using IOP<21 mm Hg and IOP<18 mm Hg thresholds, with or without glaucoma medications, and without further glaucoma surgery. Subjects were followed for at least 24 months after surgery.

RESULTS

Mean baseline IOP was comparable between the Xen Gel Microstent and KDB goniotomy groups (23.7±8.4 and 25.9±7.9 mm Hg, respectively, P =0.32). At 24 months after surgery, the mean IOP after Xen Gel Microstent was 14.7±3.2 mm Hg (32.7% reduction from baseline, P =0.018) and KDB goniotomy was 16.7±3.2 mm Hg (40.4% reduction from baseline, P =0.049). Although the mean IOP was significantly lower during the first month after Xen Gel Microstent implantation, no difference in mean IOP was observed between the 2 treatment groups at 24 months after surgery ( P =0.416). At 24 months after surgery, the percent reduction of IOP from baseline was not significantly different between the 2 groups. The mean reduction of glaucoma medications from baseline at 24 months was 1.69 drops after Xen Gel Microstent implantation ( P =.008) and 1.67 drops after KDB goniotomy ( P =0.038). Postoperative complications were nonvision-threatening and were not significantly different between the 2 groups ( P =0.550). Interventions not included with complications were needling performed in 21 (37%) of eyes in the Xen Gel Microstent group and Nd:YAG goniopuncture in 1 (5.6%) eye after KDB goniotomy. With an IOP threshold <21 mm Hg, surgical success was not significantly different between the 2 groups ( P =0.06). At a lower IOP threshold (<18 mm Hg), surgical success was higher after Xen Gel Microstent implantation compared with KDB goniotomy ( P =0.001).

CONCLUSIONS

Both stand-alone Xen Gel Microstent implantation and KDB goniotomy can effectively and safely reduce IOP for moderate to severe glaucoma. The Xen Gel Microstent was associated with a higher need for postoperative interventions and achieved greater success at a lower IOP threshold.

Ab Interno Goniotomy with the Kahook Dual Blade in a Monocular Patient with Mucous Membrane Pemphigoid and Refractory Open Angle Glaucoma: A Case Report

Purpose

To describe the case of a monocular patient with ocular mucous membrane pemphigoid (MMP) and open angle glaucoma refractory to medical treatment, who was successfully managed with ab interno goniotomy at the time of cataract surgery.

Methods

A 63-year-old woman with a history of severe MMP presented with exacerbation of the disease in both eyes. Vision was 20/80 in the right eye and light perception in the left eye. Symblepharon formation, trichiasis and forniceal foreshortening were present in the right eye, while the cornea of the left eye was completely conjunctivalized. Following aggressive systemic immunosuppressive therapy with corticosteroids and cyclophosphamide, the disease was brought under control. However, the patient developed a mature cataract and high intraocular pressure (IOP) of 28 mmHg on maximal medical therapy. Due to the high risk of ocular MMP exacerbation with glaucoma filtration surgery, the decision was made to proceed with cataract extraction combined with ab interno goniotomy with the Kahook Dual Blade.

Results

There were no intraoperative complications. The IOP has remained in the 12–14 mmHg range without any topical glaucoma medications over a total follow up of 3.5 years.

Conclusion

Ab interno goniotomy using the Kahook Dual Blade can significantly reduce IOP and medication burden in MMP cases, where any type of conjunctival incisional surgery could induce disease flare up. In this case, it represented a safe and effective surgical procedure for ocular MMP with concomitant refractory open angle glaucoma.

Six months' follow-up of combined phacoemulsification-kahook dual blade excisional goniotomy

PURPOSE

This study reports on the combination of excisional goniotomy and cataract extraction in the management of glaucoma in terms of intraocular pressure (IOP) and glaucoma medication reduction.

METHODS

This is a retrospective case series. Twenty-eight eyes of 22 patients with the diagnosis of cataract and ocular hypertension or glaucoma of any stage underwent combined phacoemulsification and Kahook Dual Blade (KDB) goniotomy, between March 2019 and September 2020. The parameters evaluated were postoperative best-corrected visual acuity, mean IOP reduction, number of IOP-lowering medications, and the surgical success rate defined as IOP reduction >20% and/or reduction in glaucoma medications >1.

RESULTS

The mean IOP reduction at 6 months was 4.5 mmHg (P = 0.0007), which translates to 24.9% reduction from preoperative IOP. The mean preoperative number of glaucoma medications was 2.9 ± 1.0 (median of 3). It was reduced to 1.1 ± 1.1 (median of 1.5), 1.46 ± 1.17 (median of 2), 1.44 ± 1.28 (median of 2), and 1.56 ± 1.28 (median of 2) at 1 week, 1 month, 3 months, and 6 months, respectively. Twenty-nine percent (8/28) of the patients were off glaucoma medications at 6 months and 46% (13/28) had a reduction of more than 50% of their glaucoma medications.

CONCLUSION

Combined phacoemulsification-KDB excisional goniotomy may be an effective and safe alternative to more invasive filtering surgery in glaucoma patients of any stage.

Selective Laser Trabeculoplasty and Outcomes of Subsequent Phacoemulsification Combined with Kahook Dual Blade Goniotomy

Introduction

To investigate the relationship between intraocular pressure (IOP)-lowering success of selective laser trabeculoplasty (SLT) and combined phacoemulsification/Kahook Dual Blade (phaco/KDB) goniotomy in eyes with mild to severe open angle glaucoma (OAG).

Methods

Eyes undergoing combined phaco/KDB goniotomy and that had previously undergone SLT were analyzed. Data collected included demographics, glaucoma type and severity, IOP, and topical IOP-lowering medications before and after both procedures. Eyes were divided into two groups based on success of SLT, defined as IOP reduction of at least 20% maintained on at least two consecutive follow-up visits without any subsequent medication additions or interventions. Phaco/KDB goniotomy success was defined as IOP reduction of at least 20% and/or reduction in the number of IOP-lowering medications of at least one up to 12 months of follow-up.

Results

Overall, SLT was successful in 20 of 43 eyes (46.5%), of which 63.6% (7/11) had successful phaco/KDB goniotomy at 12 months follow-up. Among eyes with unsuccessful SLT, 60.0% (9/15) had successful phaco/KDB at 12 months follow-up. Phaco/KDB success rate was similar in patients regardless of their previous response to SLT at all postoperative time points up to 12 months follow-up (p = 0.87).

Conclusions

The presence or lack of IOP-lowering response to SLT did not influence the success rate of subsequent phaco/KDB goniotomy in eyes with mild to severe OAG. Patients who did not respond to SLT still benefited from phaco/KDB goniotomy at a later date.

Efficacy of Combined Phacoemulsification and Goniosynechialysis in Primary Angle Closure Disease With Different Degrees of Peripheral Anterior Synechiae

PRCIS

Phacoemulsification and goniosynechialysis (Phaco-GSL) was equally effective in the treatment of primary angle-closure disease (PACD) with preoperative peripheral anterior synechiae (PAS) <180 degrees and larger than 180 degrees. Patients with a larger preoperative PAS range required more range of mechanical separation intraoperatively and displayed more recurrence of PAS (re-PAS) range postoperatively.

PURPOSE

To evaluate the long-term efficacy of combined phaco-GSL in PACD with different extent of PAS.

PATIENTS AND METHODS

A retrospective study was conducted on 67 patients (79 eyes) who received phaco-GSL. The patients were divided into 2 groups according to the extent of PAS (group A: PAS ≤180 degrees; group B: PAS >180 degrees). Changes in intraocular pressure (IOP), the number of anti-glaucoma drugs, intraoperative mechanical separation of PAS and range of re-PAS during the last follow-up ≥12 months were analyzed.

RESULTS

At baseline, eyes in group B presented with higher IOP and more anti-glaucoma drugs usage ( P =0.008 and 0.004). The PAS range, IOP, number of anti-glaucoma medication were reduced both in 2 groups at the final visit. The range of mechanical separation intraoperatively and re-PAS postoperatively were both larger in group B ( P =0.002 and <0.001). The postoperative re-PAS range was positively correlated with the range of mechanical separation ( R2 =0.17). The complete success rates at 12, 24, 36, and 48 months were 86.8%, 71.1%, 71.1%, and 71.1% in group A; and 80.5%, 74.6%, 69.9%, and 69.9% in group B. The qualified success rates were 100%, 96.6%, 92.0%, and 92.0% in group A; and 100%, 89.5%, 85.1%, and 85.1% in group B.

CONCLUSION

Phaco-GSL for the treatment of PACD showed equally effective IOP control regardless of the extent of preoperative PAS.

Intraocular Pressure and Medication Burden With Cataract Surgery Alone, or Cataract Surgery Combined With Trabecular Bypass or Goniotomy

PRCIS

When compared with cataract surgery in glaucoma patients, trabecular micro-bypass and goniotomy resulted in a large decrease in the incidence of intraocular pressure (IOP) spikes, a modest effect on IOP, and a minimal effect on medication burden.

PURPOSE

To compare changes in IOP and ocular hypotensive medications in 3 surgical cohorts: cataract surgery, cataract surgery with trabecular micro-bypass (cataract/trabecular), and cataract surgery with goniotomy (cataract/goniotomy).

MATERIALS AND METHODS

We included 138 eyes diagnosed with open-angle glaucoma: (1) 84 eyes with cataract surgery alone, (2) 25 eyes with cataract/trabecular surgery, and (3) 29 eyes with cataract/goniotomy surgery. We compared the groups for postoperative IOP and the number of ocular hypotensive medications. We adjusted for preoperative IOP, and preoperative and postoperative number of ocular hypotensive medications. We defined an IOP spike as IOP ≥21 mm Hg and 10 mm Hg higher than preoperative on postoperative day 1.

RESULTS

All 3 surgeries showed a decrease in IOP (P≤0.004) and medication burden (P≤0.001) at 3 and 6 months postoperatively when compared with their own preoperative baselines. When compared with cataract surgery alone, cataract/trabecular and cataract/goniotomy had similar IOP lowering at 1 month postoperatively, and variable results at 3 and 6 months. The change in ocular hypotensive medications was not statistically different between the surgical groups at any postoperative visit. Cataract/trabecular and cataract/goniotomy decreased IOP on postoperative day 1, and had relative risk reduction of ~70% for IOP spikes (P≤0.001 for both).

CONCLUSION

Trabecular micro-bypass and goniotomy when added to cataract surgery resulted in a large decrease in IOP spikes, a modest effect on IOP, and a minimal effect on medication burden when compared with cataract surgery alone in glaucoma patients.

Predictive Factors of Outcomes in Kahook Dual Blade Excisional Goniotomy Combined with Phacoemulsification

Aim

To identify factors that were significant predictors of Kahook Dual Blade (KDB) excisional goniotomy outcomes.

Materials and methods

One hundred and thirty-two eyes from 99 adult glaucoma patients who underwent combined KDB and phacoemulsification (KDB-phaco) with a minimum 6-month follow-up were assessed for baseline patient characteristics to determine correlation to the success of KDB-phaco at 6 and 12 months postoperatively. Success was defined as ≥20% intraocular pressure (IOP) reduction or ≥1 medication reduction as well as IOP ≤18 mm Hg without any additional IOP-lowering procedures after KDB-phaco.

Results

63.6% (84/132) and 46.1% (41/89) of cases were successful at the 6- and 12-month follow-ups, respectively. KDB-phaco reduced patient's preoperative IOP (in mm Hg) from 17.6 ± 4.6 to 14.9 ± 3.2 at 6 months (15.3%, p < 0.001) and 15.4 ± 4.7 at 12 months (12.5%, p = 0.001). KDB-phaco reduced patient's preoperative IOP-lowering medications from 2 ± 1.2 to 1.1 ± 1.2 at 6 months (45%, p < 0.001) and 1.32 ± 1.3 at 12 months (34%, p < 0.001). At 6 months, patients on >1 IOP lowering medication had a greater chance of meeting our success criteria (p = 0.037). Visually significant postoperative hyphema was not associated with the use of anticoagulation (p = 0.943) but was significantly associated with postoperative day 1 IOP ≤ 10 mm Hg (p = 0.011).

Conclusion

Patients who underwent KDB-phaco significantly reduced their IOP and medication burden at both 6 and 12 months compared with their baseline preoperative values. KDB-phaco outcome was associated with higher baseline IOP-lowering medications and increased rate of hyphema was associated with lower postoperative day 1 IOP, regardless of anticoagulation status. Age, ethnicity, prior laser trabeculoplasty, type and severity of glaucoma, and baseline preoperative IOP were not associated with surgical success.

Clinical significance

Patients with a higher number of baseline medications may experience a greater probability of success following KDB-phaco.

How to cite this article

Pratte EL, Cho J, Landreneau JR, et al. Predictive Factors of Outcomes in Kahook Dual Blade Excisional Goniotomy Combined with Phacoemulsification. J Curr Glaucoma Pract 2022;16(1):47-52.

Histological analysis of trabeculotomy - An investigation on the intraocular pressure lowering mechanism

The primary aim of trabeculotomy (TLO) and/or minimally invasive glaucoma surgery (MIGS) is to produce a direct communication between the anterior chamber (AC) and collector channels (CC), which is believed to be the process by which intraocular pressure (IOP) is normalized. However, we previously reported our finding of the large opening of the Schlemm's canal (SC) into the AC in eyes with failed TLO (Amari et al., 2015). If the routes from the AC to the CC by TLO/MIGS are direct, IOP should be stabilized at around aqueous vein pressure if the SC and CC are undamaged. However, in eyes in which TLO/MIGS is successful, IOP usually stays at around the middle or high teens post surgery. In this current study, we retrospectively investigated the specific reason for middle- or high-teens IOP following TLO/MIGS via the histological examination of trabeculectomy (TRAB) specimens that include the area of previous TLO/MIGS in eyes with failed TLO or insufficient IOP control following TLO by specifically focusing on the behavior of the SC endothelium (SCE). Patient background, maximum IOP prior to TLO/MIGS and TRAB, the number medications administered, and elapsed time between TLO/MIGS and TRAB were reviewed. In 42 TRAB specimens of 31 120-180° TLO eyes (Group A; 27 ab-externo and 4 ab-interno eyes) and 11 360° suture TLO eyes (Group B), SC length (SCL), the site of the incision in the trabecular meshwork (TM) [i.e., the center (CEN)/anterior-tip (TIP)], and TM opening into the AC [i.e., open (OPN)/closed (CLS)] were histologically investigated. The correlation between the clinical parameters of the maximum IOP of pre-TLO/MIGS, the maximum IOP of pre-TRAB, the percentage of IOP reduction (PIR), and the histological results were statistically evaluated. Our findings revealed a significant negative correlation between the maximum IOP of pre-TRAB and SCL (P = 0.0167), and a significantly higher PIR in the eyes with OPN than those with CLS in Group A (P = 0.0045). However, no significant difference in SCL was found between the OPN and CLS eyes in both groups. In comparison to Group A, a higher percentage of OPN (82%) yet a smaller SCL (P = 0.0024) was observed in Group B. No significant correlation between clinical and histological parameters was found in Group B. In both groups, the common finding was sealing of the SC openings by SC endothelium (SCE) and no direct communication between the AC and the CC. This fact indicates that the nature by which SCE seals off the opened SC lumen into the AC created by TLO may be very important for maintaining the blood-aqueous barrier. Based on these results, we concluded that accessibility for aqueous humor to the SC and preservation of the SC may be important for lowering IOP by TLO. However, the opening of the SC into the AC (OPN type) does not guarantee an adequate IOP lowering effect if the SC is widely collapsed. Thus, TLO may be improved only by eliminating the most resistant part of the TM with minimal SCE damage.

Early Results of Irrigating Goniectomy With TrabEx+: A Novel Device for the Treatment of Open-angle Glaucoma

PRCIS

Irrigating goniectomy with the TrabEx+ device can lower intraocular pressure (IOP) in patients with glaucoma, as a standalone procedure or combined with cataract surgery.

PURPOSE

The aim was to describe the efficacy and safety of irrigating goniectomy performed using the TrabEx+ device, either as a standalone procedure or combined with cataract surgery, in eyes with medically treated open-angle glaucoma.

METHODS

A retrospective case series of eyes treated by a single surgeon at a single UK teaching hospital. Data was collected at follow-up visits at 1 week, 3, 6, 12, 18, and 24 months postoperatively. Primary outcomes included IOP and glaucoma medication reduction after surgery. Proportion of eyes achieving >20% IOP reduction, IOP <21 mm Hg, and no reoperation were classified as surgical success.

RESULTS

Seventy-three consecutive eyes of 64 patients (mean age 68.4±13.7 y) were enrolled. 62% were treated as combined procedures with cataract surgery. Overall, mean IOP decreased from 31.3±7.3 to 20.9±10.4 mm Hg at the latest follow-up (34% reduction) (P<0.001) at the latest follow-up (16.1±10.3 mo) with mean preoperative medications decreased from 2.9±1.2 to 1.9±1.3 (P<0.001). 73% met the definition of success at latest follow-up. Postoperative complications were recorded including hyphaema (17%), uveitis (3%), hypotony (1%), and persistent vitreous hemorrhage (1%). Eighteen percent required reoperation because of treatment failure.

CONCLUSION

TrabEx+ appears to be effective in lowering IOP and medication with or without cataract surgery. However, long-term safety and efficacy will be better understood in a prospective study with longer follow-up.

Outcomes of combined single-use dual blade goniotomy and cataract surgery

Purpose

Single-use dual blade goniotomy (SBG) is a novel ab interno procedure that removes three to five clock hours of trabecular meshwork (TM). We analysed the reduction of intraocular pressure (IOP) and topical glaucoma medication (Meds) in eyes following combined cataract surgery and SBG (Cat-SBG).

Methods

IOP and Meds were evaluated retrospectively in 55 eyes of 38 patients. 44 eyes had high tension glaucoma (HTG) and eleven eyes had normal tension glaucoma (NTG). Complete success (no Meds) and qualified success (with Meds) for IOP levels ≤ 21, ≤ 18 , ≤ 16 mmHg or ≥ 20% IOP reduction at the two- and six-month follow-up were evaluated.

Results

IOP and Meds were significantly reduced from before to two months after Cat-SBG in HTG- and NTG-patients (HTG: IOP 19.4 ± 3.3 to 15.1 ± 3.3 mmHg; p < 0.001; Meds 2.1 ± 1.3 to 0.8 ± 1.3; p < 0.001; NTG: IOP 14.0 ± 2.3 to 11.5 ± 2.3 mmHg; p = 0.004; Meds 1.6 ± 0.7 to 0.3 ± 0.7; p < 0.001). IOP and Meds did not change significantly from two to six months after Cat-SBG.

In HTG, complete and qualified success rates were 43% (19/44) and 93% (41/44) for IOP ≤ 18 mmHg, 36% (16/44) and 64% (28/44) for IOP ≤ 16 mmHg and 30% (13/44) and 43% (19/44) for ≥ 20% IOP reduction six months after surgery. In NTG, complete and qualified success was 81% (9/11) and 100% (11/11) for IOP ≤ 18 and ≤ 16 mmHg, and 27% (3/11) for IOP reduction ≥ 20%.

IOP and Meds reduction were comparable between HTG and NTG eyes.

Only minor postoperative complications occurred.

Conclusion

Cat-SBG is an efficient method to significantly lower IOP in patients with HTG and NTG.

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

Purpose

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

Observations

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

Conclusions and importance

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

The effects of antithrombotic therapy in ab interno trabeculotomy with a spatula-shaped microhook

To evaluate the effects of the discontinuation of antithrombotic drugs on intraocular pressure (IOP) reduction and complications from ab interno trabeculotomy for patients with glaucoma. We performed a retrospective chart review on the data of patients treated with antithrombotic agents who have undergone ab interno trabeculotomy through Tanito microhook combined with cataract surgery at the Asahi General Hospital and the Tokyo University Hospital, with 6 months of follow-up. The patients were classified into two groups depending on whether they discontinued (AT-) or continued (AT+) antithrombotic therapy during the perioperative phase. The demographics, pre- and postoperative IOP, medication score, best-corrected visual acuity (BCVA), and postoperative complications were analyzed preoperatively and postoperatively at 1 week and 1–6 months. The series included 44 eyes from 44 Japanese patients. The AT- and AT+ groups included 21 eyes from 21 patients and 23 eyes from 23 patients, respectively. The decrease in IOP from the baseline at 1 week postoperative was significantly different between the two groups (p = 0.009), but there were no significant differences observed in the other visits. Hyphema and IOP spikes exceeding 30 mmHg occurred in 10% and 10% of AT- participants, and in 43% and 26% of AT+ participants, respectively. Hyphema and spikes with hyphema occurred more frequently in the AT+ than in the AT- group (p = 0.02 and p = 0.05). The number of patients who had spikes was not significantly different (p = 0.27). In trabeculotomy using the Tanito microhook®, discontinuing antithrombotic therapy had better IOP-lowering effects and less postoperative complications.

A Review of Excisional Goniotomy Performed with the Kahook Dual Blade for Glaucoma Management

Aim

To review the published literature describing clinical outcomes of excisional goniotomy using the Kahook Dual Blade (KDB) for the management of glaucoma.

Background

A family of less invasive glaucoma procedures-including excisional goniotomy with the KDB-has been developed to provide moderate reductions in intraocular pressure and/or medication burden in eyes with therapeutic needs that may not warrant the risks associated with more traditional procedures such as trabeculectomy and tube-shunt implantation. This review's goal is to synthesize the existing literature into a compendium of excisional goniotomy's indications, technique, efficacy and safety outcomes, and optimal place in glaucoma management.

Review results

Excisional goniotomy with the KDB effectively lowers IOP and reduces the medication burden in eyes with POAG and other forms of glaucoma across the spectrum of both baseline IOP and disease severity. The procedure exhibits a safety profile that is on par with other angle-based surgical interventions and enhanced safety compared to filtration procedures. It can be performed by comprehensive ophthalmologists as well as glaucoma specialists. This procedure as a standalone operation delivers IOP reductions consistent with filtration surgery, and in combination with cataract surgery delivers both IOP and medication reductions at least as great as other minimally invasive procedures.

Conclusion

Given the broad base of evidence supporting its use in a wide variety of clinical scenarios, excisional goniotomy with the KDB can play a meaningful role in the achievement of patient-specific glaucoma therapy goals.

Clinical significance

These aggregate findings support the efficacy and safety of excisional goniotomy with the KDB and clarify the patient profiles best suited for this procedure.

How to cite this article

Dorairaj S, Radcliffe NM, Grover DS, et al. A Review of Excisional Goniotomy Performed with the Kahook Dual Blade for Glaucoma Management. J Curr Glaucoma Pract 2022;16(1):59-64.

Gonioscopy-assisted transluminal trabeculotomy versus goniotomy with Kahook dual blade in patients with uncontrolled juvenile open-angle glaucoma: a retrospective study

Background

To compare the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) and Kahook Dual Blade (KDB) excisional goniotomy in patients with uncontrolled juvenile open-angle glaucoma (JOAG).

Methods

Thirty-three patients (46 eyes) were included in this single-center, retrospective, comparative study and treated with GATT (36 eyes) or KDB goniotomy (13 eyes). Intraocular pressure (IOP), number of glaucoma medications, adverse events, and additional anti-glaucoma procedures were collected during pre- and postoperative visits. Surgical success was defined as 6 mmHg ≤ IOP ≤ 18 mmHg and ≥ 20% IOP reduction from baseline with (partial success) or without (complete success) IOP-lowering medications.

Results

The mean ± SD preoperative IOP was 30.48 ± 12.9 mmHg and 26.08 ± 13.1 mmHg (P = 0.164) on 3.71 ± 0.46 and 3.08 ± 0.86 (P = 0.023) glaucoma medications in GATT and KDB group, respectively. At 3 months, the mean ± SD IOP was 15.48 ± 5.93 mmHg and 20.0 ± 10.8 mmHg after GATT and KDB, respectively (P = 0.072). The percentage of IOP lowering from baseline was 44.4 in the GATT group and 14.1 in the KDB group (P = 0.011). The mean reduction in medications was 2.6 ± 1.7 and 0.8 ± 1.2 three months after GATT and KDB, respectively (P < 0.001). Cumulative proportion of partial and complete success were 65.6 and 44.7% in the GATT group, 30.8 and 15.4% in the KDB group at 6 months. Additional procedures were required in 13.9% of cases after GATT and in 61.5% after KDB (P = 0.001). Patients in the GATT group with prior anti-glaucoma procedures and postoperative IOP spikes were more likely to fail, while those with complete trabeculotomy had a better prognosis.

Conclusions

Reduction of IOP and medications were greater after GATT in uncontrolled JOAG eyes. Whereas, more additional IOP-lowering procedures were required after KDB goniotomy.

Trial registration

This study was registered under the Chinese Clinical Trial Registry (ChiCTR2000034172, 27/06/2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02159-z.

Trends and Usage Patterns of Minimally Invasive Glaucoma Surgery in the United States: IRIS® Registry Analysis 2013-2018

PURPOSE

Understanding trends and patterns in the use of minimally invasive glaucoma surgery (MIGS) and patient profiles undergoing each procedure is important given their relative expense and unknown long-term safety and effectiveness.

DESIGN

Retrospective analysis.

PARTICIPANTS

Minimally invasive glaucoma surgeries and standard glaucoma surgeries recorded in the American Academy of Ophthalmology Intelligent Research in Sight (IRIS®) Registry.

METHODS

We used the data from IRIS Registry between 2013 and 2018 (inclusive) to measure the annual number of MIGS and standard surgical techniques (trabeculectomy or glaucoma drainage device [GDD] placement) performed in the United States, stratified by demographic characteristics. Secondary analyses of concurrent surgeries and of subsequent surgeries for MIGS and standard surgical technique also were conducted.

MAIN OUTCOME MEASURES

Trends and sociodemographic characteristics of MIGS use in the United States.

RESULTS

Two hundred three thousand three hundred thirty-two eyes and 232 537 unique procedures had associated, documented International Statistical Classification of Diseases and Related Health Problems (ICD), Ninth or Tenth Revision, codes for glaucoma and were included in final analyses. Among eyes with documented glaucoma diagnoses, a substantial increase in annual MIGS procedures occurred over the study period (from 7586 in 2013 to 39 677) and a smaller decrease in standard glaucoma procedures (from 16 215 to 13 701). The proportion of iStent procedures almost tripled during the study period (from 14% to 40%), and by 2017 accounted for almost half (43.7%) of all glaucoma surgeries in the United States. Twenty-one thousand twenty-five of all eyes (10.3%) underwent multiple procedures: 7638 (36.3%) on the same day and 13 387 (63.7%) on subsequent days. Endocyclophotocoagulation and iStent placement were the most common concurrent procedures (55.4% of all concurrent procedures). Trabeculectomy and GDD placement were most commonly followed by another standard glaucoma surgery, but when followed by sequential MIGS, endocyclophotocoagulation and goniotomy were the most common procedures performed (33.0% and 21.9%, respectively).

CONCLUSIONS

A significant increase in MIGS use occurred over the recent 6-year period, despite limited evidence of their long-term safety or effectiveness, highlighting the need for trials comparing safety and outcomes of novel MIGS versus traditional surgical treatments for glaucoma.

Comparison of effectiveness and complications in trabeculotomy with phacoemulsification between ab externo and ab interno using a spatula-shaped microhook

To compare the short-term surgical effectiveness and safety profile of trabeculotomy ab externo and ab interno with microhook in terms of the recovery of visual acuity. A retrospective chart review was performed on patients who underwent trabeculotomy combined with phacoemulsification and lens implantation at Asahi General Hospital, with 6 months of follow-up. The patients treated by trabeculotomy were classified into two groups depending on the surgical procedures: ab interno with Tanito microhook (TMH) and ab externo with rigid probe trabeculotome (LOT). The demographics, preoperative and postoperative intraocular pressure (IOP), number of medications (Med), best-corrected visual acuity (BCVA), surgical-induced astigmatism (SIA), and postoperative complications were analyzed at pre-operation, and 1 week and 1–6 months post-operation. Fifty-two eyes of 38 Japanese patients underwent TMH and 42 eyes of 32 patients underwent LOT. The decreases in IOP and Med from the baseline were significant at all time points in both groups (p < 0.001), but there were no significant differences between the two groups. BCVA improved significantly in TMH and LOT after the operation (p < 0.001). BCVA and SIA significantly improved, mostly at 1 week in TMH, compared with LOT (p = 0.02 and 0.003). Hyphema and IOP spike exceeding 30 mmHg (spike) occurred in 11% and 6% of participants in TMH, and 33% and 26% of participants in LOT, respectively. Hyphema and IOP spike occurred more frequently in the LOT than in the TMH group (p = 0.01 and 0.005). Ab interno trabeculotomy showed similar IOP-lowering effects as ab externo, but had less postoperative complications.

Initial experience with phacoemulsification and goniotomy using the Kahook dual blade in advanced open-angle glaucoma: Six-month outcomes in Indian eyes

Purpose:

The aim of this study was to report our initial experience on the outcomes of phacoemulsification in combination with goniotomy using the Kahook Dual Blade (KDB) in eyes with advanced open-angle glaucoma (OAG).

Methods:

The outcomes of phaco-goniotomy with KDB in advanced OAG in Indian eyes were retrospectively analyzed. Based on the Hodapp-Anderson-Parrish criteria of visual field defects, severe glaucoma (mean deviation on standard automated perimetry worse than 12 dB) was considered as advance glaucoma. Preoperative, intraoperative, and postoperative data were collected through 6 months of follow-up. Outcome measures included antiglaucoma medications (AGM), the proportion of eyes achieving >1AGM reduction, intraocular pressure (IOP), and visual acuity.

Results:

Median (interquartile range) number of AGM in eyes that underwent phaco-KDB goniotomy reduced from 2 (2,3) at baseline to 1 (0,1) at 6 months (P = 0.002). Median IOP reduced from 20 (20,26) mmHg at baseline to 14 (12,15) mmHg at 6 months (P = 0.02). The proportion of eyes achieving >1 medication reduction was 88% eyes (8/9). Adverse events noted were IOP spike (22 mmHg) in 2 eyes and intra-op hyphema in 1 eye on postoperative day-1, both resolved in a week with conservative management. Except one eye with central corneal scar due to prior pterygium surgery, 8 eyes had 20/20 vision at 1 week which was maintained till last follow-up.

Conclusion:

Phacoemulsification with KDB Goniotomy significantly lowered the need for AGM with moderate IOP reduction in advanced OAG eyes. There were no serious complications and the visual recovery was good and early.

Management of hypotony-related maculopathy after combined phacoemulsification and trabeculectomy: January consultation #1

A 59-year-old man with mild to moderate pigmentary glaucoma was referred for management of hypotony-related maculopathy 3 years after combined phacoemulsification and trabeculectomy in his right eye. His ocular history is significant for retinal detachment in the right eye that was surgically treated with a pars plana vitrectomy and scleral buckle 5 years prior to the current presentation and 1 year prior to his combined phacoemulsification-trabeculectomy procedure. After trabeculectomy, he reportedly had a wound leak with hypotony and choroidal effusion. The patient was referred to a second surgeon who performed a bleb revision with a pericardial patch graft, but the patient had a severe intraocular pressure (IOP) spike in the immediate postoperative period requiring suture removal. This resulted in recurrent hypotony with maculopathy. A second bleb revision with pericardial patch graft was performed but was not successful in raising the IOP out of the single digits or in resolving the maculopathy. Accordingly, the patient was referred for further assessment. At presentation, the patient's corrected distance visual acuity was 20/100 in the right eye and 20/20 in the left eye. Applanation tonometry IOP was 4 mm Hg and 16 mm Hg for the right and left eyes, respectively. Central corneal thickness was 609 μm in the right eye and 574 μm in the left eye. The right pupil was noted to be slightly irregular with a relative afferent pupillary defect. Slitlamp examination of the right eye was notable for a moderately elevated, Seidel test-negative bleb, and deep anterior chamber. The left eye had a Krukenberg spindle and mild nuclear sclerotic cataract but was otherwise unremarkable. Fundus examination of the right eye was notable for significant macular folds with edematous nerve fiber layer (NFL) and optic nerve. The left optic nerve and fundus examination were unremarkable. Gonioscopy revealed open angles with dense trabecular meshwork pigment in both eyes. There was a nicely patent superior sclerostomy in the right eye. There was no cyclodialysis cleft. Optical coherence tomography (OCT) of the macula showed chorioretinal folds and NFL edema in the right eye and was normal in the left eye (Figure 1JOURNAL/jcrs/04.03/02158034-202101000-00022/figure1/v/2021-01-04T143903Z/r/image-tiff). The OCT of the optic nerve in the right eye was distorted secondary to the chorioretinal folds, whereas the left eye was notable for mild superior thinning of the NFL (Figure 2JOURNAL/jcrs/04.03/02158034-202101000-00022/figure2/v/2021-01-04T143903Z/r/image-tiff). Humphrey visual field revealed a superior nasal step in the right eye (Figure 3JOURNAL/jcrs/04.03/02158034-202101000-00022/figure3/v/2021-01-04T143903Z/r/image-tiff). Axial lengths were 25.33 mm and 26.53 mm in the right and left eye, respectively; it is notable that the right eye had a shorter axial length despite the scleral buckle, which demonstrates the degree of axial shortening from hypotony (Figure 4JOURNAL/jcrs/04.03/02158034-202101000-00022/figure4/v/2021-01-04T143903Z/r/image-tiff). What would be your approach for managing this patient's hypotony? Does the fact that the referring surgeon had performed 2 failed bleb revision procedures prior to referral influence your approach? Given that a previous attempt at revision resulted in an extreme IOP spike would you also recommend a glaucoma procedure? If so, what procedure would you perform? Would you do it coincident with the revision or in a staged procedure later on an as-needed basis?

Excisional goniotomy vs trabecular microbypass stent implantation: a prospective randomized clinical trial in eyes with mild to moderate open-angle glaucoma

PURPOSE

To compare reduction in intraocular pressure (IOP) and IOP-lowering medication in eyes undergoing excisional goniotomy with Kahook Dual Blade (KDB) vs iStent microbypass implantation, both combined with phacoemulsification, in eyes with mild to moderate open-angle glaucoma (OAG).

SETTING

Nine practices in the United States.

DESIGN

Prospective, randomized, active-controlled, parallel-group clinical trial.

METHODS

Eyes were randomized to KDB-Phaco or iStent-Phaco group. Demographics, corrected distance visual acuity, IOP, IOP-lowering medications, and adverse events were collected at baseline and at day 1, week 1, and months 1, 3, 6, and 12 postoperatively. The primary outcome measure was the proportion of eyes at 12 months with IOP reduction of 20% or greater or IOP medication reduction of 1 or more compared with baseline.

RESULTS

For this study, 164 eyes of 164 patients were analyzed (82 in each group). Mean IOP was reduced at 12 months compared with baseline from 18.5 (standard of error 0.4) to 15.4 (0.4) mm Hg in the KDB-Phaco group and from 18.5 (0.3) to 16.1 (0.4) mm Hg in the iStent-Phaco group (P = .24). Mean IOP-lowering medications were reduced from 1.3 (0.1) to 0.3 (0.1) in the KDB-Phaco group and from 1.4 (0.1) to 0.4 (0.1) in the iStent-Phaco group (P = .17). Among study completers, the primary outcome was attained in 74 (93.7%) of 79 patients of KDB-Phaco eyes and 65 (83.3%) of 78 patients of iStent-Phaco eyes (P = .04). Both procedures had similar safety profiles.

CONCLUSIONS

Both procedures lowered both IOP and the need for IOP-lowering medications effectively and safely in eyes with mild to moderate OAG and cataract. Significantly, more KDB-Phaco eyes than iStent-Phaco eyes met the primary outcome of 20% or greater IOP reduction or 1 or more medication reduction at 12 months.

Effects of Preoperative Intraocular Pressure Level on Surgical Results of Microhook Ab Interno Trabeculotomy

To assess the roles of preoperative intraocular pressure (IOP) level on the IOP reducing efficacy of microhook ab interno trabeculotomy (µLOT), 126 consecutive open-angle glaucomatous eyes (90 primary open angle glaucoma, 36 exfoliation glaucoma) of 126 Japanese subjects (60 men, 66 women; mean age ± standard deviation, 70.5 ± 11.4 years) who underwent µLOT alone (25 eyes, 20%) or combined µLOT and cataract surgery (101 eyes, 80%) were retrospectively included, and subdivided into four groups based on the quartile of preoperative IOP: Q1, ≤15 mmHg; Q2, 15–18 mmHg, Q3, 18–21 mmHg, and Q4, >21 mmHg. Preoperative and 12 months postoperative IOPs and numbers of antiglaucoma medications were compared among IOP groups. Factors associated with postoperative IOP were assessed using multivariate analysis, and the success of IOP control was assessed with various definitions. Postoperatively, IOP was significantly higher in Q3 (p < 0.0146) and Q4 (p = 0.0320) groups than Q1 group, while the number of medications was not significantly different among four IOP groups (p = 0.1966). Older age was associated with lower postoperative IOP, and higher preoperative IOP was associated with higher postoperative IOP, while sex, glaucoma type, surgical procedure, lens status, extent of trabeculotomy incision, and preoperative number of medications were not associated with postoperative IOP. The success rates for IOP ≤ 18 and ≤15 mmHg were higher in lower preoperative IOP groups (i.e., Q1 and Q2) than higher preoperative IOP groups (Q3 and Q4), while the success rate for ≥20% IOP reduction was higher in higher preoperative IOP groups than in lower preoperative IOP groups; the success rate for ≥0% IOP reduction was equivalent among groups. By reviewing the previous studies in ab interno trabeculotomy/goniotomy procedures, positive correlation between preoperative and postoperative IOPs was preserved throughout the studies and surgical procedures. After the µLOT, larger %IOP reduction was achieved in higher preoperative IOP groups than in lower preoperative IOP groups, while postoperative IOP was still lower than in lower preoperative IOP groups.

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.

Relationship between selective laser trabeculoplasty and excisional goniotomy outcomes in glaucomatous eyes

OBJECTIVE

To evaluate the relationship between intraocular pressure (IOP)-lowering success with selective laser trabeculoplasty (SLT) and Kahook Dual Blade (KDB) goniotomy in eyes with glaucoma.

DESIGN

Retrospective chart review.

PARTICIPANTS

30 eyes of 24 patients undergoing phacoemulsification combined with a KDB with 6 months follow-up and who had previously undergone SLT in the same eye.

METHODS

Data collected from electronic health records included demographic and glaucoma status, IOP and IOP-lowering medication after SLT and KDB. SLT and KDB success were defined as IOP reduction ≥20% or medication reduction ≥1 at 2 and 6 months, respectively.

MAIN OUTCOME

Association between SLT success and KDB success.

RESULTS

Overall, SLT was successful in 17 of 30 eyes (56.7%) at 2 months, and KDB was successful in 18 of 30 eyes (60%) at 6 months. Nine of 17 eyes (52.9%) with prior successful SLT had successful subsequent KDB, whereas 9 of 13 (69.2%) with prior unsuccessful SLT had successful KDB. There was no significant relationship between SLT and KDB outcome in these 30 eyes (p = 0.465 by Fisher's exact test).

CONCLUSION

No relationship between success of SLT and subsequent KDB was observed. However, patients with history of failed SLT still benefited from subsequent KDB.

Safety and efficacy of incisional goniotomy as an adjunct with phacoemulsification in primary angle-closure glaucoma

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of incisional goniotomy as an adjunct to phacoemulsification in primary angle-closure glaucoma (PACG) patients.

METHODS

Consecutive patients with PACG (high or borderline IOP) deemed fit for phacoemulsification were enrolled. After phacoemulsification, incisional goniotomy was performed with or without goniosynechialysis. Patient demographic profile, clinical data, and adverse events, if any, were analyzed during at least a 6-month follow-up period. Success was defined as IOP of 18 mm Hg or lesser with or without medications.

SETTING

Tertiary care Ophthalmic hospital.

DESIGN

Prospective interventional case series.

RESULTS

Of 46 eyes (38 patients) included, 69.6% eyes were classified as having advanced glaucoma. The mean treated IOP decreased by 7.3 ± 1.0 (SE) mm Hg (95% CI, 5.2-9.3) from 21.4 ± 6.6 to 14.2 ± 3.7 mm Hg at a mean duration of 11.7 ± 5.5 months (6-22 months) postoperatively (P < .001, paired t test). There was 66.6% reduction in median number of hypotensive medications (P < .001, Wilcoxon signed-rank test). Observed complications included hyphema (13 eyes [28%]), IOP spike (3 eyes [6.5%]), and cyclodialysis (1 eye [2.17%]). High treated IOP and number of medications were significantly associated with failure in univariate analysis (P < .05, Fisher exact test). The cumulative survival probability for qualified success at 22 months was 87.8% ± 0.07 (95% CI, 0.65-0.96).

CONCLUSIONS

Incisional goniotomy as an adjunct with phacoemulsification resulted in a significant and sustained reduction in IOP along with decrease in number of glaucoma medications in chronic PACG eyes, irrespective of the disease stage.

Safety profile of minimally invasive glaucoma surgery

PURPOSE OF REVIEW

This article reviews the safety profile of trabecular meshwork/Schlemm's canal-based, subconjunctival, and suprachoroidal minimally invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Prospective randomized clinical trials and metaanalyses published during the 2019-2020 review period provided important data regarding the safety profile of trabecular meshwork/Schlemm's canal-based MIGS. Transient hyphema and intraocular pressure spikes are among the most common complications associated with this category of MIGS, but more serious adverse events such as cyclodialysis cleft formation may also occur. Trabecular bypass microstents and the intracanalicular scaffold are further subject to device-related complications, including malposition and obstruction. Recent case reports and retrospective case series have further characterized the safety profile of the subconjunctival gel stent, with adverse events ranging from self-limited hypotony to visually devastating endophthalmitis and suprachoroidal hemorrhage. Five-year results of the COMPASS XT study demonstrated significantly greater endothelial cell loss in patients randomized to receive CyPass Micro-Stent (Alcon Laboratories, Fort Worth, TX, USA) in combination with cataract surgery versus those who underwent cataract surgery alone, and ultimately led to a Food and Drug Administration Class I recall of the device.

SUMMARY

Trabecular meshwork/Schlemm's canal-based procedures are generally among the safest MIGS, with mostly self-limited and nonvision-threatening complications. Subconjunctival gel stent insertion is associated with both bleb-related and stent-specific adverse events, which are similar to those observed with trabeculectomy and tube shunt surgery, respectively. Removal of the CyPass Micro-Stent from the market underscores the need for high-quality, long-term safety data regarding MIGS.

Midterm Results of Microhook ab Interno Trabeculotomy in Initial 560 Eyes with Glaucoma

All the 560 glaucomatous eyes of 375 Japanese subjects (181 men, 194 women; mean age ± standard deviation, 76.0 ± 13.2 years) who underwent microhook ab interno trabeculotomy (µLOT) alone (159 eyes, 28%) or combined µLOT and cataract surgery (401 eyes, 72%) performed by one surgeon at Matsue Red Cross Hospital between May 2015 and March 2018 to control intraocular pressure (IOP) were retrospectively assessed. Preoperative and postoperative IOPs, numbers of antiglaucoma medications, the logarithm of the minimum angle of resolution visual acuity (logMAR VA), anterior chamber (AC) flare, visual field mean deviation (MD), and corneal endothelial cell density (CECD) were compared up to 36 months. Surgical complications and required interventions were described. The duration of the follow-up was 405 ± 327 (range, 2–1326) days. The mean preoperative IOP (20.2 ± 7.0 mmHg) and number of antiglaucoma medications (2.8 ± 1.1) decreased to 13.9 ± 4.5 mmHg (31% reduction, p < 0.0001) and 2.5 ± 1.0 (11% reduction, p < 0.0001), respectively, at the final visit. After combined surgery, compared with preoperatively, the final VA improved 0.11 logMAR (p < 0.0001), AC flare increased 4.5 photon counts/msec (p = 0.0011), MD improved 0.6 decibel (p < 0.0001), and the CECD decreased 6% (p < 0.0001). Layered hyphema (172 eyes, 31%) and hyphema washout (26 eyes, 5%) were the most common postoperative complication and intervention, respectively. At the final visit, 379 (69%) eyes achieved successful IOP control of ≤18 mmHg and ≥20% IOP reduction, and 349 (64%) eyes achieved successful IOP control of ≤15 mmHg and ≥20% IOP reduction. Older age, steroid-induced glaucoma, developmental glaucoma, and the absence of postoperative complications were associated with lower final IOP; exfoliation glaucoma, other types of glaucoma, and higher preoperative IOP were associated with higher final IOP. µLOT has a significant IOP-lowering potential in patients with glaucoma, and improves visual function when combined with cataract surgery.

Twelve-month surgical outcome and prognostic factors of stand-alone ab interno trabeculotomy in Japanese patients with open-angle glaucoma

The purpose of the study was to evaluate the 12-month surgical outcome and prognostic factors of stand-alone ab interno trabeculotomy. The changes in the intraocular pressure (IOP) and medication score and the success rate of the surgery were analyzed. Thirty-four eyes of 29 patients with primary open-angle glaucoma (POAG; n = 16) or pseudoexfoliation glaucoma (PEG; n = 18) with a 12-month follow-up period were included in the study. The decreases in IOP and medication score from the baseline to the all-time-point were statistically significant (P < 0.001). The surgical success rates were 97.1%, 76.5%, and 44.0% at 3 months (90 days), 6 months (180 days), and 12 months (365 days), respectively. A mixed effect Cox model revealed that the type of glaucoma (POAG) was significantly associated with surgical failure (P = 0.044). Furthermore, the surgical success rate was significantly higher in eyes with PEG than it was in those with POAG (P = 0.019). Stand-alone ab interno trabeculotomy significantly lowered both the IOP and the medication score in patients with glaucoma, although almost one quarter of the cases needed additional glaucoma surgeries. The surgical success rate was significantly higher in eyes with PEG than it was in those with POAG.

Turn Back Elevation of Once Reduced IOP After Trabeculotomy Ab Externo and Kahook Dual Blade Surgeries Combined with Cataract Surgery

Purpose

To evaluate the surgical outcome of internal trabeculectomy by Kahook dual blade (KDB) with that of external trabeculotomy, each combined with phaco-lensectomy and intraocular lens implantation (Phaco).

Patients and Methods

This is a retrospective comparative study. The primary and secondary outcome measures are postsurgical intraocular pressure and postsurgical hyphema. One eye each of 76 primary open angle glaucoma (POAG), pseudoexfoliation glaucoma (PEG) and ocular hypertension (OH) patients underwent external phaco-trabeculotomy, and that of 40 POAG, PEG and OH patients underwent phaco-KDB surgery.

Results

Reduction of the intraocular pressure (IOP) by phaco-KDB at one and two years was 28.4 and 27.8%, respectively, and was not significantly different from that by external phaco-trabeculotomy of 32.7% (P=0.256) and 31.5% (P=0.468), respectively. Three months postsurgical IOP after phaco-KDB and external phaco-trabeculotomy was 16.1 and 15.9 mmHg, respectively. There was a significant turn back elevation of once reduced IOP to 17.1 (P=0.0207) and 17.0 mmHg (P=0.0096) at 24 months, respectively. There were no differences in success probability to achieve IOP below 17 mmHg (P=0.120), 21 mmHg (P=0.719) and >20% IOP reduction (P=0.309) with medication(s) at two years between the phaco-KDB and external phaco-trabeculotomy cohorts. Younger age was a significant (P<0.001) risk factor for failure; however, presurgical IOP (P=0.466), the type of surgery (P=0.219) and presence of postsurgical IOP spike (P=0.737) were not significant risk factors by the Cox proportional hazard model. Hyphema and spike of the IOP in phaco-KDB and external phaco-trabeculotomy cohorts were 40% and 88% (P<0.001), and 53% and 41% (P=0.238), respectively.

Conclusion

The IOP reduction by the phaco-KDB was equivalent to that by external phaco-trabeculotomy up to two years. In both cohorts, once reduced postsurgical IOP tend to increase up to 24 months.

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.

Comparison of 12-Month Outcomes of Kahook Dual Blade Excisional Goniotomy Performed by Attending versus Resident Surgeons

Objective Kahook Dual Blade goniotomy (KDB) has proven effective in lowering intraocular pressure (IOP) and reducing the medication burden in patients with glaucoma. This study compares outcomes up to 12 months postoperatively after KDB combined with phacoemulsification (phaco-KDB) between an ophthalmology attending and residents.

Methods A retrospective analysis was performed on 160 eyes of 113 patients who received a phaco-KDB performed by either an ophthalmology attending or a resident under direct guidance of the attending. Data for each patient was collected preoperatively and at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively. The primary outcome measure was surgical success, defined as 20% IOP reduction or at least 1 medication reduction at 12 months. The secondary outcome measures included mean IOP and medication reduction at each postoperative time point, adverse events, operating time, and survival time, defined as time to failure to meet the criteria for surgical success or requiring a secondary IOP-lowering procedure.

Results Preoperative mean IOP was comparable between the two groups (p = 0.585), while baseline medications were higher in the attending group (p = 0.040). Rate of successful outcomes was similar in both groups at 12 months (73.3% attending vs. 87.5% residents, p = 0.708). Mean IOP reduction (1.7 vs. 4.3%, p = 0.278) and medication reduction (0.7 vs. 0.6, p = 0.537) also did not differ at 12 months. Presence of adverse events was similar between the groups (21.6 vs. 27.3%, p = 0.938). The survival time was significantly longer in the attending group (356.3 ± 20.2 days vs. 247.1 ± 26.8 days, p = 0.003). Resident cases took ∼10 minutes longer compared with attending cases (p < 0.001).

Conclusion IOP lowering outcomes and rate of adverse events of KDB were similar whether the primary surgeon was an attending or a resident surgeon. The survival time was significantly longer in the attending group, but overall success rate was 77.5% for both groups. This suggests phaco-KDB is an effective procedure that can be safely performed by a trainee under direct supervision of an experienced surgeon.