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

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.

Comparison of tube shunt implantation and trabeculectomy for glaucoma: a systematic review and meta-analysis

OBJECTIVE

To compare the efficacy and safety of tube shunt implantation with trabeculectomy in the treatment of patients with glaucoma.

METHODS

A systematic literature search was performed for studies comparing tube with trabeculectomy in patients with glaucoma (final search date: 27 February 2022). Comparisons between tube and trabeculectomy were grouped by the type of tube (Ahmed, Baerveldt, Ex-PRESS and XEN). The primary endpoints included intraocular pressure (IOP), IOP reduction (IOPR), IOPR percentage (IOPR%), complete success rate (CSR), qualified success rate (QSR) and adverse events (AEs).

RESULTS

Forty-nine studies were included in this meta-analysis and presented data for 3795 eyes (Ahmed: 670, Baerveldt: 561, Ex-PRESS: 473, XEN: 199, trabeculectomy: 1892). Ahmed and Ex-PRESS were similar to trabeculectomy in terms of IOP outcomes and success rate (Ahmed vs trabeculectomy: IOPR%: mean difference (MD)=1.34 (-5.35, 8.02), p=0.69; Ex-PRESS vs trabeculectomy: IOPR%: MD=0.12 (-3.07, 3.31), p=0.94). The IOP outcomes for Baerveldt were worse than those for trabeculectomy (IOPR%: MD=-7.51 (-10.68, -4.35), p<0.00001), but the QSR was higher. No significant difference was shown for the CSR. XEN was worse than trabeculectomy in terms of IOP outcomes (IOPR%: MD=-7.87 (-13.55, -2.18), p=0.007), while the success rate was similar. Ahmed and Ex-PRESS had a lower incidence of AEs than trabeculectomy. Baerveldt had a lower incidence of bleb leakage/wound leakage, hyphaema and hypotonic maculopathy than trabeculectomy but a higher incidence of concurrent cataracts, diplopia/strabismus and tube erosion. The incidence of AEs was similar for the XEN and trabeculectomy procedures.

CONCLUSION

Compared with trabeculectomy, both Ahmed and Ex-PRESS appear to be associated with similar ocular hypotensive effects and lower incidences of AEs. However, Baerveldt and XEN cannot achieve sufficient reductions in IOP outcomes similar to those of trabeculectomy.

PROSPERO REGISTRATION NUMBER

CRD42021257852.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

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

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

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

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.

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.

Factors associated with lamina cribrosa displacement after trabeculectomy measured by optical coherence tomography in advanced primary open-angle glaucoma

PURPOSE

To investigate the relationship of lamina cribrosa displacement to corneal biomechanical properties and visual function after mitomycin C-augmented trabeculectomy.

METHOD

Eighty-one primary open-angle eyes were imaged before and after trabeculectomy using an enhanced depth spectral domain optical coherence tomography (SDOCT). Corneal biomechanical properties were measured with the ocular response analyzer before the surgery. The anterior lamina cribrosa (LC) was marked at several points in each of the six radial scans to evaluate LC displacement in response to intraocular pressure (IOP) reduction. A Humphrey visual field test (HVF) was performed before the surgery as well as 3 and 6 months, postoperatively.

RESULTS

Factors associated with a deeper baseline anterior lamina cribrosa depth (ALD) were cup-disc ratio (P = 0.04), baseline IOP (P = 0.01), corneal hysteresis (P = 0.001), and corneal resistance factor (P = 0.001). After the surgery, the position of LC became more anterior (negative), posterior (positive), or remained unchanged. The mean LC displacement was - 42 μm (P = 0.001) and was positively correlated with the magnitude of IOP reduction (regression coefficient = 0.251, P = 0.02) and negatively correlated with age (regression coefficient = - 0.224, P = 0.04) as well as baseline cup-disk ratio (Regression coefficient = - 0.212, P = 0.05). Eyes with a larger negative LC displacement were more likely to experience an HVF improvement of more than a 3 dB gain in mean deviation (P = 0.002).

CONCLUSION

A larger IOP reduction and younger age was correlated with a larger negative LC displacement and improving HVF. The correlation between lower SDOCT cup-disc ratio and postoperative negative LC displacement was borderline (P = 0.05). Corneal biomechanics did not predict LC displacement.