Access to Schlemm's canal for canaloplasty: an intra-individual comparison of two dissection techniques.

PURPOSE: To compare a modified incision technique with classic scleral flap dissection for canaloplasty with canal expander regarding efficacy and safety. METHODS: In a prospective randomized pilot study of 32 eyes of 16 patients with primary open-angle glaucoma, access to Schlemm's canal was created by deep lamellar dissection (scleral flap excision, group 1) or by vertical cut-down incision (group 2). Following canal opening and viscodilation with microcannula and sodium hyaluronate, two Stegmann Canal Expanders were implanted, and the scleral flap or vertical incision, respectively, was closed watertight. RESULTS: Mean preoperative intraocular pressure (IOP) was 34.9 mmHg ± 6.7 [standard deviation (SD)] in group 1 and 33.8 mmHg ± 7.7 (SD) in group 2 (p = 0.66); mean postoperative IOP without medications was 14.3 mmHg ± 2.9 (SD) in group 1 and 14.8 mmHg ± 5.2 (SD) in group 2 at 1 month (p = 0.76), and 14.4 mmHg ± 1.9 (SD) in group 1 and 16.8 mmHg ± 3.1 (SD) in group 2 at 12 months (p = 0.01). Overall, there was a significant preoperative-postoperative IOP difference between groups (19.4 mmHg ± 10.1, group 1; 16.6 mmHg ± 8.9, group 2; p = 0.02). Surgery type had a significant effect when adjusted for preoperative IOP, cup-disc ratio, eye side, follow-up number and surgery type (p < 0.01, anova). No filtering bleb was observed in either group. Intra- and postoperative complications were rare and included peripheral Descemet's membrane detachment (3), microhyphema (2) and cannulation into the anterior chamber (1). CONCLUSIONS: In this intra-individual comparative study of ab externo canaloplasty with the canal expander, IOP reduction was substantial in both groups and slightly greater in the group with deep scleral flap excision. Additional IOP reduction by transscleral drainage through the Descemet's membrane window and intrascleral lake is suggested.

Flap-sparing canaloplasty: a modified approach to Schlemm's canal.

PURPOSE: To present a modified surgical technique for canaloplasty with the Stegmann Canal Expander obviating the need for lamellar scleral dissection. METHODS: After limbal peritomy of the conjunctiva, the sclera is not dissected in the classic lamellar fashion with superficial and deep scleral flaps but is successively 'scratched' down by radial incision until Schlemm's canal (SC) is opened (trench cut). Following canal opening and viscodilation with a microcannula and sodium hyaluronidate, one Stegmann Canal Expander is implanted on either side of the canal ostia and the scleral incision is closed watertight. RESULTS: Twenty-seven eyes with primary open-angle glaucoma (POAG) were consecutively operated on using this modified technique. In all eyes, SC was successively opened, but exposure of the choroid and rupture of trabeculo-Descemet's membrane with iris prolapse or filtering blebs were not found. Adverse events included trimming of the expander in one eye for incomplete implantation during surgery, and transient microhyphaema in five eyes post-surgery. Mean intraocular pressure (IOP) was 31.9 mmHg ± 6.0 (SD) before surgery and 14.0 mmHg ± 2.5 (SD) 6 months and 15.2 mmHg ± 1.95 (SD) 12 months after surgery. CONCLUSIONS: The flap-sparing, trench-cut incision technique may reduce the risk of complications in canaloplasty with the Stegmann Canal Expander while effectively lowering IOP in POAG patients.

Canaloplasty with Stegmann Canal Expander for primary open-angle glaucoma: two-year clinical results.

PURPOSE: To examine longer-term postsurgical safety and efficacy of a new expander for Schlemm's canal. METHODS: In a non-comparative, prospective study, 42 White patients with medically uncontrolled primary open-angle glaucoma (POAG) underwent primary canaloplasty with >2-year follow-up. The bleb-independent procedure comprised catheter-assisted canaloplasty and implantation of two Stegmann Canal Expanders to maintain trabecular distension and canal patency over 180°. Intraocular pressure (IOP), glaucoma medication use and complications were assessed. RESULTS: Mean IOP was 26.8 ± 5.6 mmHg presurgery, 12.8 ± 1.5 mmHg at 6 months, 13.2 ± 1.2 mmHg at 12 months and 13.3 ± 2.5 mmHg at 24 months (p < 0.001). Rate of complete success, defined as IOP ≤21, ≤18 and ≤16 mmHg and a ≥ 30% IOP reduction, was 85% (95% CI: 0.76-0.95), 85% (0.76-0.95) and 82% (0.70-0.96) at 12 months and 83% (0.73-0.94), 80% (0.70-0.92) and 80% (0.70-0.92) at 24 months. Preoperative factors were not significant predictors of ≤16 mmHg IOP reduction: IOP (hazard ratio [HR]: 0.68; 95% CI: 0.44-1.04; p = 0.08), mean visual defect (1.06; 0.90-1.20; p = 0.47), number of medications (0.59; 0.17-2.14; p = 0.42) and age (0.96; 0.87-1.13; p = 0.41). Number of medications dropped from 2.8 ± 0.4 presurgery to 0.2 ± 0.5 postsurgery (p < 0.001). Mean preoperative best-corrected visual acuity was 0.19 ± SD 0.21 (range: 0-1.6), and logMAR was similar to 0.23 ± 0.16 (range: 0-1.6; p = 0.42) after a mean follow-up of 27.4 months. Complications included peripheral Descemet's membrane detachment (7.2%) and trimming of the expander (4.7%) during surgery, and transient microhyphaema (23.8%) and IOP elevation (7.2%) postsurgery. CONCLUSION: Canaloplasty with the Stegmann Canal Expander was a safe and effective procedure to reduce IOP in White patients with moderate to advanced POAG.

A New Expander for Schlemm Canal Surgery in Primary Open-angle Glaucoma-Interim Clinical Results.

PURPOSE: To evaluate a new canal expander in circumferential viscocanalostomy (canaloplasty) for whites with primary open-angle glaucoma (POAG). DESIGN: Prospective, single-center, noncomparative study. PARTICIPANTS: Twenty-two eyes of 22 consecutive patients with medically uncontrolled POAG underwent primary viscocanalostomy and implantation of the Stegmann Canal Expander into Schlemm canal with a follow-up time of at least 1 year. MATERIALS AND METHODS: Schlemm canal was unroofed ab externo, and dilated with viscoelastic material and microcatheter. The Stegmann Canal Expander is a flexible, fenestrated hollow implant of 9 mm in length. One expander was implanted into either side of the surgically created of ostium to keep the Schlemm canal permanently open. The superficial scleral flap was closed watertight. Laser goniopuncture of the trabeculo-Descemet membrane window was performed if postoperative intraocular pressure (IOP) exceeded 16 mm Hg. MAIN OUTCOME MEASURES: Complete successes were defined as a confirmed IOP≤21, ≤18, and ≤16 mm Hg without medications, respectively, combined with a 30% IOP reduction. Number of antiglaucomatous medications, best-corrected visual acuity, and intraoperative and postoperative complications were recorded. RESULTS: The mean IOP dropped from 27.1±5.3 mm Hg preoperatively to 13.6±1.6 mm Hg at 6 months, 13.0±1.5 mm Hg at 9 months, and 13.1±2.2 mm Hg at 12 months (P<0.001). The complete success rates for an IOP≤21, ≤18, and ≤16 mm Hg combined with a 30% IOP reduction were 91% [95% confidence interval (CI), 0.80-1.0], 91% (95% CI, 0.80-1.0), and 91.0% (95% CI, 0.80-1.0) at 6 months, and 86% (95% CI, 0.73-1.0), 82% (95% CI, 0.67-1.0), and 82.0% (95% CI, 0.67-1.0) at 12 months. The success rate of an IOP≤16 mm Hg without medications did not depend on age [hazard ratios (HR) 1.02; 95% CI, 0.85-1.12; P=0.74], preoperative IOP (HR 0.97; 95% CI, 0.83-1.23; P=0.89), and mean visual defect (HR 1.05; 95% CI, 0.72-1.27; P=0.76). Laser goniopuncture was performed on 2 eyes (9%) 4.1 months postoperatively; the mean IOP was 19.5 mm Hg before and 13.6 mm Hg after goniopuncture. The number of medications dropped from 2.9±0.6 before surgery to 0.05±0.2 after surgery (P<0.001). The postoperative best-corrected visual acuity at last visit (0.12±0.09; range, 0 to 0.39) was comparable to preoperative values (mean±SD, 0.16±0.10; range, 0 to 0.39) (P=0.35). Minor intraoperative or postoperative complications included microhyphema (8 eyes) and transient elevated IOP (steroid responder; 2 eyes). CONCLUSIONS: Implantation of the Stegmann Canal Expander in canaloplasty lowered IOP significantly in POAG without complications related to the device in this 1-year observation period.

Novel device for expanding Schlemm's canal: a morphological study: Implantation of the Stegmann Canal Expander following viscodilation of Schlemm's canal resulted in permanent expansion of the canal lumen and distension of the trabecular meshwork without complications.

This study was performed to assess any changes in Schlemm's canal (SC) in human autopsy eyes possibly resulting from the injection of a viscoelastic substance and implantation of a new device (the Stegmann Canal Expander, SCE) into SC. After the surgical procedure, eyes were fixed, dissected into quartered segments and examined using light and scanning electron microscopy. Tissue sections displayed a marked dilation of SC and of the collector channels compared with untreated control sections. The SC walls were disrupted in some areas due to viscodilation, but not due to SCE implantation. In all eyes, the entire 9-mm length of the SCE was positioned inside the canal, keeping the canal wide open. The SCE diameter of 240 µm remained unchanged after implantation. Injection of a viscoelastic substance into SC leads to marked dilation of SC and collector channels. Implanting the SCE into SC allowed persistent expansion of SC and stretching of the trabecular meshwork. This may increase the permeability of the trabecular meshwork, reduce its resistance to aqueous humour and maintain circumferential flow within SC. Experimental and clinical studies should determine the impact of this new canal expander in terms of lowering intraocular pressure in glaucoma surgery.

Long-term results of up to 12 years of over 700 cases of viscocanalostomy for open-angle glaucoma.

PURPOSE: To study the safety and long-term efficacy of classic viscocanalostomy in patients with open-angle glaucoma (OAG) in different populations. METHODS: A total of 726 eyes of 726 patients from Europe or South Africa with primary OAG (POAG) and pseudoexfoliative glaucoma (PXFG) were included in this retrospective multicentre study. Complete (qualified) success was defined as an intraocular pressure (IOP) equal to or lower than 21, 18 and 16 mmHg without (with or without) medications, respectively. A failed procedure was defined if IOP was above 21 mmHg, not controllable by laser goniopuncture or medications. RESULTS: The mean IOP before surgery was 42.6 ± 14.2 mmHg for all patients, 29.6 ± 6.6 mmHg for European patients and 48.1 ± 12.9 mmHg for African patients. The follow-up time was 86.2 ± 43.1 months. Mean IOP was 15.4 ± 3.6 mmHg at 5 years, 15.5 ± 4.4 mmHg at 10 years and 16.8 ± 4.2 mmHg at 15 years. The qualified success rate for an IOP of 21, 18 or 16 mmHg or less after 5 years was 92% [95% confidence interval (CI) 0.88-0.96], 70% (95% CI 0.63-0.77) and 43% (95% CI 0.36-0.51) in European patients, and 90% (95% CI 0.87-0.93), 77% (95% CI 0.74-0.81) and 67% (95% CI 0.63-0.72) in African patients, respectively. There was no difference between the success rate for POAG and PXFG for an IOP of 21, 18 or 16 mmHg or less at 5 years (p = 0.64, p = 0.20, p = 0.22, respectively). Laser goniopuncture was performed postoperatively on a total of 127 eyes (17.7%), lowering the pressure from 23.1 ± 1.9 mmHg to 15.0 ± 2.2 mmHg. There were no significant complications, in particular, no blebitis or endophthalmitis. CONCLUSION: Viscocanalostomy produced a sustained long-term reduction of IOP with a low-risk profile in European and African patients with OAG over 12 years.

Canaloplasty for primary open-angle glaucoma: long-term outcome.

BACKGROUND/AIMS: To study the safety and effectiveness of 360° viscodilation and tensioning of Schlemm canal (canaloplasty) in black African patients with primary open-angle glaucoma (POAG). METHODS: Sixty randomly selected eyes of 60 consecutive patients with POAG were included in this prospective study. Canaloplasty comprised 360° catheterisation of Schlemm's canal by means of a flexible microcatheter with distension of the canal by a tensioning 10-0 polypropylene suture. RESULTS: The mean preoperative intraocular pressure pressure (IOP) was 45.0 ± 12.1 mm Hg. The mean follow-up time was 30.6 ± 8.4 months. The mean IOP at 12 months was 15.4 ± 5.2 mm Hg (n=54), at 24 months 16.3 ± 4.2 mm Hg (n = 51) and at 36 months 13.3 ± 1.7 mm Hg (n=49). For IOP ≤ 21 mm Hg, complete success rate was 77.5% and qualified success rate was 81.6% at 36 months. Cox regression analysis showed that preoperative IOP (HR = 1.003, 95% CI = 0.927 to 1.085; p = 0.94), age (HR = 1.000, CI = 0.938 to 1.067; p = 0.98) and sex (HR = 3.005, CI=0.329 to 27.448; p=0.33) were all not significant predictors of IOP reduction to ≤ 21 mm Hg. Complication rate was low (Descemet's detachment n=2, elevated IOP n = 1, false passage of the catheter n = 2). CONCLUSION: Canaloplasty produced a sustained long-term reduction of IOP in black Africans with POAG independent of preoperative IOP. As a bleb-independent procedure, canaloplasty may be a true alternative to classic filtering surgery, in particular in patients with enhanced wound healing and scar formation.

Clinical evaluation of the aqueous outflow system in primary open-angle glaucoma for canaloplasty.

PURPOSE: To assess the aqueous outflow pathway in primary open-angle glaucoma (POAG) through provocative gonioscopy and channelography with a flexible microcatheter and fluorescein tracer during canaloplasty. METHODS: One eye each was randomly selected from 28 consecutive black African POAG patients undergoing canaloplasty. Provocative gonioscopy was performed at the beginning of surgery, and blood reflux from collector channels into Schlemm's canal (SC) was semiquantitatively evaluated. During canaloplasty, a flexible microcatheter injected fluorescein tracer stepwise into SC. The outflow pathway parameters of interest were blood reflux, transtrabecular passage of fluorescein, and episcleral vein filling. RESULTS: Mean age, intraocular pressure (IOP), and cup-to-disc ratio were 45.9 years (SD +/- 13.3), 41.0 mm Hg (SD +/- 11.9), and 0.78 (SD +/- 0.22), respectively. Mean IOP (P < 0.001) and episcleral venous egress (P = 0.01) correlated significantly with blood reflux, but cup-to-disc ratio (P = 0.71), age (P = 0.70), and fluorescein diffusion (P = 0.90) did not. A multinomial regression model showed that higher IOP (P < 0.001, OR, 1.687; 95% CI, 1.151-2.472) was strongly associated with poor blood reflux, independent of the patient's age (P = 0.383, OR, 0.942; 95% CI, 0.823-1.078). No correlation was found between preoperative IOP, transtrabecular passage, episcleral venous egress, and cup-to-disc ratio. The mean IOP was 17.5 mm Hg (SD +/- 3.7) 6 months after surgery. The level of IOP after surgery correlated with the grade of blood reflux and episcleral venous egress (P < 0.001). CONCLUSIONS: High mean IOP may be associated with poor blood reflux and filling of SC. A collapsed canal, probably secondary to high IOP, may be an underestimated sign in black African patients with POAG. The quality of blood reflux and episcleral venous egress may both be predictive of the level of IOP after surgery. Provocative gonioscopy and channelography may reflect the function of the outflow pathway and may be helpful in assessing the surgical outcome of canaloplasty.

Posterior vertical capsulotomy with optic entrapment of the intraocular lens in congenital cataracts--prevention of capsule opacification.

PURPOSE: To present a modified surgical technique for preventing posterior capsule opacification (PCO) in children with congenital cataracts and to evaluate its long-term efficacy. SETTING: Department of Ophthalmology, Medical University of Southern Africa, Medunsa, South Africa. METHODS: Anterior and posterior vertical capsulotomy, with optic entrapment of the intraocular lens (IOL) by maintaining the anterior hyaloid, was performed in 68 cataractous eyes of children aged 2 months to 8 years (mean 3 years, 1 month). The posterior capsule was evaluated for at least 5 years for secondary opacification, IOL position, pigmentary deposits on the IOL optic, and the presence of synechias. RESULTS: Sixty-eight eyes maintained a clear visual axis for 5 to 12 years (mean 9 years, 1 month) postoperatively. No secondary procedure was necessary. In all eyes, the IOL remained well centered and entrapped. CONCLUSIONS: Posterior capsulotomy with optic entrapment of the IOL proved to be a safe and efficient surgical procedure for preventing PCO in children with congenital cataracts. Uniting the anterior and posterior capsule in front of the IOL limits the proliferation and migration of Elschnig pearls. An intact anterior hyaloid does not induce capsule opacification in association with optic entrapment; therefore, a vitrectomy is not indicated even in infants under age 5 years. Clear visual axis, centered IOL, and intact vitreous were achieved in this series; this enables a promising long-term prognosis for binocular visual development, especially because surgery was performed early.