The effect of canaloplasty with suprachoroidal drainage combined with cataract surgery - 1-year results

Advances in Canaloplasty-Modified Techniques Yield Strong Pressure Reduction with Low Risk Profile

For decades, trabeculectomy (TE) was considered the gold standard for surgical treatment of open-angle glaucoma owing to its powerful intraocular pressure (IOP)-lowering potency. However, owing to the invasive nature and high-risk profile of TE, this standard is changing, and minimally invasive procedures are becoming more preferable. In particular, canaloplasty (CP) has been established as a much gentler alternative in everyday life and is under development as a full-fledged replacement. This technique involves probing Schlemm's canal with a microcatheter and inserting a pouch suture that places the trabecular meshwork under permanent tension. It aims to restore the natural outflow pathways of the aqueous humor and is independent of external wound healing. This physiological approach results in a significantly lower complication rate and allows considerably simplified perioperative management. There is now extensive evidence that canaloplasty achieves sufficient pressure reduction as well as a significant reduction in postoperative glaucoma medications. Unlike MIGS procedures, the indication is not only mild to moderate glaucoma; today, even advanced glaucoma benefits from the very low hypotony rate, which largely avoids a wipeout phenomenon. However, approximately half of patients are not completely medication-free after canaloplasty. As a consequence, a number of canaloplasty modifications have been developed with the goal of further enhancing the IOP-lowering effect while avoiding the risk of serious complications. By combining canaloplasty with the newly developed suprachoroidal drainage procedure, the individual improvements in trabecular facility and uveoscleral outflow facility appear to have an additive effect. Thus, for the first time, an IOP-lowering effect comparable to a successful trabeculectomy can be achieved. Other implant modifications also enhance the potential of canaloplasty or offer additional benefits such as the possibility of telemetric IOP self-measurement by the patient. This article reviews the modifications of canaloplasty, which has the potential to become a new gold standard in glaucoma surgery via stepwise refinement.

[Modifications of canaloplasty : Strong pressure-lowering effect with a low risk profile]

Trabeculectomy still achieves the strongest intraocular pressure (IOP) reduction of all glaucoma surgical techniques, but with the drawback of a significant risk profile. Against this background, canaloplasty has established itself as a much gentler alternative which achieves sufficient IOP reduction and enables a significant reduction in postoperative glaucoma medication. However, approximately half of patients are not completely medication free. In response, a number of modifications have been developed with the goal of further enhancing the IOP-lowering effect of canaloplasty, but without the risk of serious complications. By combining canaloplasty with the newly developed suprachoroidal drainage, a uveoscleral drainage is created in addition to the trabecular outflow improvement, which seems to have an additive effect. Thus, for the first time, an IOP-lowering effect comparable to successful trabeculectomy can be achieved. Numerous other modifications with implants also enhance the potential of canaloplasty or offer other additional benefits such as the possibility of telemetric IOP self-measurement by the patient. The additional creation of a subconjunctival drainage with or without use of cytostatic drugs also seems promising. Ab interno procedures, on the other hand, have limited pressure-lowering potential but may provide some additional benefit in mild glaucoma and in the setting of cataract surgery.

Modified suture-assisted canaloplasty in Asians with primary open-angle glaucoma: a prospective study with 12-month follow-up

BACKGROUND

To evaluate the efficacy and safety of modified suture-assisted canaloplasty in Asians with primary open-angle glaucoma (POAG).

METHODS

A prospective, consecutive cases study, evaluating a modified canaloplasty by twisted 6/0 suture was performed on Asian POAG patients. Three modifications of this canaloplasty included opening the Schlemm's canal by viscocanalostomy, circumferential probing by a twisted 6/0 suture and loose suture of the superficial scleral flap. The twisted 6/0 suture was selected as a prober based on characteristical analysis of size and contact measurement as well as chemical composition conducted among 5/0, twisted 6/0 polypropylene sutures and the microcatheter. Success criteria were defined as intraocular pressure (IOP) ≤ 21 mmHg, 18 mmHg, 15 mmHg, and ≥ 20% reduction without (complete success) or with medications (qualified success). Efficacy was assessed by the success rate of circumferential catheterization, IOP values, the success rate of the surgery, the number of IOP-lowering medications, best-corrected vision acuity (BCVA), cup-to-disc ratio (C/D), and mean deviation (MD). Safety was evaluated by adverse events.

RESULTS

Forty eyes from 40 consecutive patients were included with a mean follow-up of 14.8 ± 3.0 months. Circumferential catheterization was successfully conducted in 36 eyes (90%). Mean IOP decreased from 26.2 ± 6.9 mmHg to 14.5 ± 2.7 mmHg at 12 months postoperatively. While medication numbers were reduced from 3.2 ± 0.6 to 0.5 ± 0.8 at month 12 (both p < 0.001). Qualified success rate was 97.2% [95% confidence interval (CI) 0.92-1.03], 86.1% (95% CI 0.74-0.98) and 66.7% (95% CI 0.51-0.83) at 12 months with three criteria. BCVA, C/D and MD did not show progression at 1-year follow-up (p > 0.05). Age, baseline IOP, and spherical equivalent negatively influenced the success rate significantly (all p < 0.05). Adverse events included hyphema (30.6%), IOP spike > 25 mmHg (8.3%), and peripheral synechia to the trabecular-Descemet's membrane (2.7%).

CONCLUSION

Twisted 6/0 suture can be an ideal material for cannulation. Modified suture-assisted canaloplasty is an effective, safe alternative with a cost-efficient feature for patients with POAG, especially in developing countries.

TRIAL REGISTRATION

This trial was registered in the Chinese Clinical Trial Registry ( ChiCTR1900028618 , 29/12/2019).

[Treatment of postoperative endophthalmitis : Operate or only inject?]

BACKGROUND

Postoperative endophthalmitis is among the most feared complications encountered after intraocular surgery. A prompt diagnosis and initiation of treatment are crucial for the visual prognosis, which also depends on the causative microorganism. Despite advances in prevention and the availability of more epidemiological data, most of the evidence for treatment dates back to a single study, the early vitrectomy study (EVS) carried out in the early 1990s. The EVS showed that vitrectomy with intravitreal antibiotics was superior to intravitreal antibiotics alone, only when visual acuity was light perception or below. The addition of systemic antibiotics did not have any benefits. Over the last 30 years, however, surgical techniques have continued to evolve and the medicinal options have also been expanded. Moreover, the EVS examined only endophthalmitis after cataract surgery and strictly speaking the results cannot be transferred to endophthalmitis from other causes.

OBJECTIVE

This review discusses the current evidence for the different treatment modalities of the most important types of postoperative endophthalmitis.

CONCLUSION

The EVS provided important guidelines for the initial management of endophthalmitis and these guidelines remain relevant to this day; however, in view of the refinement of surgical techniques, novel treatment options, especially the nowadays continuously growing number of intravitreal injections and even some new antibiotics, it would be desirable if new controlled trials addressing the treatment of endophthalmitis would be performed.

Predictive factors for the IOP reduction in phacocanaloplasty with suprachoroidal drainage

PURPOSE

Although the pressure-reducing effect of cataract surgery alone is not very high, it is often cited in the literature. Some authors describe predictive factors correlated with the IOP (intraocular pressure) reduction: in particular noteworthy are age, axial length, preoperative pressure level and the ratio of preoperative pressure/anterior chamber depth. The aim of this study was to determine the applicability of these predictive factors to phacocanaloplasty with suprachoroidal drainage. Setting Eye Clinic Sulzbach Germany.

DESIGN

Retrospective study with a 12-month follow-up, including patients that underwent phacocanaloplasty with suprachoroidal drainage between 2012 and 2014.

METHODS

Preoperatively, baseline information was collected (including age, diagnosis, medication), and the patients underwent a basic examination and optical biometry. To investigate the relationship between preoperative parameters and the IOP reduction, Pearson's correlation analysis and linear regression were used. Patients with missing data pre- or postoperatively were excluded from the analysis.

RESULTS

The study comprised 89 patients. Mean preoperative IOP was 23.0 ± 5.3 mmHg with 4.0 different antiglaucomatous eye drops. After 12 months, IOP was reduced to 12.1 ± 1.4 mmHg with a median medication of 0.0. The preoperative IOP and the ratio of preoperative IOP/anterior chamber depth were identified as predictive factors. There was no influence of axial length and anterior chamber depth.

CONCLUSION

Unlike in cataract surgery, anterior chamber depth and axial length have no influence on the pressure reduction caused by phacocanaloplasty. However, a strong predictive factor is the preoperative pressure level. The higher the preoperative IOP, the greater the postoperative pressure reduction.

Progression on canaloplasty for primary open angle glaucoma

As a non-penetrating glaucoma surgery (NPGS), canaloplasty aims to reconstruct the physiological outflow of aqueous humor by dilating the Schlemm's canal. Ab interno canaloplasty (ABiC), which can reconstruct the natural outflow pathways of aqueous humor in mild-to-moderate primary open angle glaucoma (POAG) patients, is a new minimally invasive glaucoma surgery (MIGS) procedure improving from traditional canaloplasty. Canaloplasty can reduce intraocular pressure (IOP) with high efficiency and security. There are no complications such as scar formation and encapsulation for this no-bleb canaloplasty.

Canaloplasty versus Nonpenetrating Deep Sclerectomy: 2-Year Results and Quality of Life Assessment

Purpose

To compare phacocanaloplasty (PC) and phaco-non-penetrating deep sclerectomy (PDS).

Methods

75 patients with uncontrolled glaucoma and cataract were randomized for PC (37 eyes) or PDS (38 eyes). Intraocular pressure (IOP) and number of medications (meds) were prospectively evaluated. Follow-up examinations were performed on days 1 and 7 and after 1, 3, 6, 12, 18, and 24 months. Surgical success was calculated. Complications and postoperative interventions were noted. Quality of life (QoL) was analyzed.

Results

Preoperatively, mean IOP and meds were comparable (P > 0.05). After 24 months, IOP significantly decreased in PC from 19.4 ± 5.9 mmHg (2.6 ± 0.9 meds) to 13.8 ± 3.3 mmHg (0.5 ± 0.9 meds) and in PDS from 19.7 ± 5.4 mmHg (2.9 ± 0.9 meds) to 15.1 ± 2.9 mmHg (1.1 ± 1.2 meds). Statistically lower IOP was observed in PC in the 6th month and persisted until 24 months (P < 0.05). No difference was found in meds (except for month 18, in which less drugs were used in PC (P = 0.001)) or success rates (P > 0.05). The most frequent complication in PC was transient hyphema (46%), in PDS bleb fibrosis (24%). PC patients during postoperative period required only goniopuncture (22% of subjects), whereas PDS patients required, in order to maintain subconjuctival outflow, subconjunctival 5-fluorouracil injections in 95% of cases (median = 3), suture lysis (34%), needling (24%), and goniopuncture (37%). NEI VFQ-25 mean composite score for PC was 78.04 ± 24.36 points and for PDS 74.29 ± 24.45 (P = 0.136). α Cronbach's correlation coefficient was 0.913.

Conclusions

PC leads to a more effective decrease in IOP than PDS in midterm observation with similar safety profiles. PDS patients required a vast number of additional procedures in contrast to PC patients, but this fact did not influence QoL.

Experimental circumferential canaloplasty with a new Schlemm canal microcatheter

AIM

To present a new, simple, inexpensive Schlemm canal microcatheter for circumferential canaloplasty in a rabbit model.

METHODS

A rabbit glaucoma animal model was established by intravitreal injection of triamcinolone acetonide. Circumferential canaloplasty with a new Schlemm canal microcatheter (patent license number: 201220029850.0) was performed. The Schlemm canal microcatheter was composed of microcatheter wall and lumen. The wall was made of high refractive index plastic optical fiber that could be attached to an illuminant so that the whole lighted microcatheter was visible during circumferential canaloplasty. The lumen could be attached to an injector for injection of viscoelastic during catheterization. Rabbits were divided randomly into the control, model and treatment groups. Intraocular pressure (IOP) was measured with a Tono-pen tonometer pre-operation and 3, 7, 14, 21 and 28d post-operation. Ultrasound biomicroscopy was performed to visualize the Schlemm canal microcatheter in the Schlemm canal and the sclera pool.

RESULTS

The Schlemm canal microcatheter could be used to perform circumferential canaloplasty in the rabbit glaucoma animal model. IOP was lower in the treatment group than that in the model group 3, 7, 14 and 28d after operation. There were no significant differences in IOP between the control group and treatment group. The differences among the three groups were statistically significant (3d: F=41.985, P<0.001; 7d: F=65.696, P<0.001; 14d: F=114.599, P<0.001; 28d: F=55.006, P<0.001).

CONCLUSION

Circumferential canaloplasty is safe and effective in control of experimental glaucoma model in rabbits.