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.

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.