Thomas W. Samuelson

Randomized Evaluation of the Trabecular Micro-Bypass Stent with Phacoemulsification in Patients with Glaucoma and Cataract

OBJECTIVE To assess the safety and efficacy of the iStent trabecular micro-bypass stent (Glaukos Corporation, Laguna Hills, CA) in combination with cataract surgery in subjects with mild to moderate open-angle glaucoma. DESIGN Prospective, randomized, open-label, controlled, multicenter clinical trial. PARTICIPANTS A total of 240 eyes with mild to moderate open-angle glaucoma with intraocular pressure (IOP) ≤24 mmHg controlled on 1 to 3 medications were randomized to undergo cataract surgery with iStent implantation (treatment group) or cataract surgery only (control). Fifty additional subjects were enrolled to undergo cataract surgery with iStent implantation under protocol expansion. Data in this report are based on the first 240 eyes enrolled. INTERVENTION Implantation of the iStent trabecular micro-bypass stent in conjunction with cataract surgery or cataract surgery only. MAIN OUTCOME MEASURES The primary efficacy measure was unmedicated IOP ≤21 mmHg at 1 year. A secondary measure was unmedicated IOP reduction ≥20% at 1 year. Safety measures included best-corrected visual acuity (BCVA), slit-lamp observations, complications, and adverse events. RESULTS The study met the primary outcome, with 72% of treatment eyes versus 50% of control eyes achieving the criterion (P<0.001). At 1 year, IOP in both treatment groups was statistically significantly lower from baseline values. Sixty-six percent of treatment eyes versus 48% of control eyes achieved ≥20% IOP reduction without medication (P = 0.003). The overall incidence of adverse events was similar between groups with no unanticipated adverse device effects. CONCLUSIONS Pressure reduction on fewer medications was clinically and statistically significantly better 1 year after stent plus cataract surgery versus cataract surgery alone, with an overall safety profile similar to that of cataract surgery alone.

Canaloplasty: Circumferential viscodilation and tensioning of Schlemm canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults : Two-year interim clinical study results

PURPOSE: To evaluate the safety and efficacy of circumferential viscodilation and tensioning of the inner wall of Schlemms canal in a new surgical procedure for the treatment of open‐angle glaucoma (OAG). SETTING: Fourteen clinical sites in the United States and Germany. METHODS: In this international multicenter prospective study of adult patients with OAG having glaucoma surgery, patients with qualifying preoperative intraocular pressure (IOP) of at least 16 mm Hg or higher and open angles were eligible. Evaluation was performed at baseline and 1 day, 1 week, and 1, 3, 6, and 12 months preoperatively. After a nonpenetrating dissection technique to expose Schlemms canal was performed, a flexible microcatheter (iTrack 250A, iScience Interventional) was used to dilate the full circumference of the canal by injecting sodium hyaluronate 1.4% (Healon GV) during catheterization. A suture loop was placed in the canal to apply tension to the trabecular meshwork. High‐resolution ultrasound imaging was used to assess Schlemms canal and anterior segment angle morphology, including distension of the trabecular meshwork caused by the tensioning suture. Data analysis was performed in 2 groups: Group 1, in which patients met all inclusion criteria, and Group 2, made up of Group 1 patients who had successful suture placement. RESULTS: Group 1 comprised 94 patients and Group 2, 74 patients. The mean baseline IOP in Group 1 was 24.7 mm Hg ± 4.8 (SD) on a mean of 1.9 ± 1.0 medications per patient. In Group 2 (patients with sutures), the mean IOP was 16.1 ± 4.7 mm Hg 3 months postoperatively, 15.6 ± 4.0 mm Hg at 6 months, and 15.3 ± 3.8 mm Hg at 1 year. Medication use dropped to a mean of 0.6 ± 0.9 per patient at 12 months. Suture tensioning was an apparent contributing factor in achieving surgical success. Patients with measurable trabecular meshwork distension from suture tension had a mean IOP of 15.9 ± 5.2 mm Hg at 6 months and 14.5 ± 3.0 mm Hg at 12 months. Surgical and postsurgical adverse events were reported in 15 of 94 patients (16%) and included hyphema (3), elevated IOP greater than 30 mm Hg (3), Descemets tear (1), hypotony (1), choroidal effusion (1), and exposed closure suture with eyelid edema and erythema epiphora (1); 4 patients were subsequently converted to trabeculectomy. CONCLUSION: Circumferential viscodilation and tensioning of Schlemms canal was a safe and effective surgical procedure to reduce IOP in adult patients with OAG.

Long-term effects of phacoemulsification with intraocular lens implantation in normotensive and ocular hypertensive eyes

PURPOSE: To evaluate the long‐term effect of phacoemulsification with intraocular lens (IOL) implantation alone in normotensive and ocular hypertensive eyes. SETTING: Private practices, Minneapolis, Minnesota, and Savannah, Georgia, USA. METHODS: The IOP before surgery, 1 year after surgery, and at the final chart recording in 588 eyes having phacoemulsification with IOL implantation was retrospectively reviewed. Before surgery, eyes were divided into 5 groups based on IOP at surgery, patient age at surgery, years of postoperative follow‐up, and a comparison between IOP at 1 year and IOP at the final check. RESULTS: The final mean IOP reduction was 6.5 mm Hg (27%) in the 31 to 23 mm Hg presurgical IOP group (n = 19), 4.8 mm Hg (22%) in the 22 to 20 mm Hg group (n = 62), 2.5 mm Hg (14%) in the 19 to 18 mm Hg group (n = 86), and 1.6 mm Hg (9%) in the 17 to 15 mm Hg group (n = 223). In the 14 to 9 mm Hg group (n = 198), the mean IOP at the final examination was 0.2 mm Hg higher (0.1% increase). CONCLUSIONS: Stratifying eyes according to presurgical IOP showed greater long‐term IOP reductions than previously reported. The reduction was proportional to the presurgical IOP. The decrease was greatest in eyes with the highest presurgical IOP. The IOP remained unchanged in eyes with the lowest presurgical IOP. The IOP reductions at 1 year were sustained over 10 years and were similar in patients of all ages.

Intraocular pressure reduction after phacoemulsification with intraocular lens implantation in glaucomatous and nonglaucomatous eyes: Evaluation of a causal relationship between the natural lens and open-angle glaucoma

PURPOSE: To study the long‐term effects of phacoemulsification with intraocular lens (IOL) implantation in nonglaucomatous and glaucomatous eyes. SETTING: Phillips Eye Institute, Minneapolis, Minnesota, and private practice, Savannah, Georgia, USA. METHODS: Intraocular pressure (IOP) after phacoemulsification with IOL implantation was retrospectively reviewed. Eyes were divided into 5 groups by preoperative IOP. Data were recorded preoperatively, 1 year postoperatively, and at the final check. Analysis included preoperative IOP versus IOP at 1 year and final IOP, percentage of eyes with elevated or reduced IOP postoperatively, patient age at surgery, and years of postoperative follow‐up. RESULTS: The study comprised 124 eyes. The final mean IOP reduction was 8.5 mm Hg (34%) in the 29 to 23 mm Hg group, 4.6 mm Hg (22%) in the 22 to 20 mm Hg group, 3.4 mm Hg (18%) in the 19 to 18 mm Hg group, and 1.1 mm Hg (10%) in the 17 to 15 mm Hg group. In the 14 to 5 mm Hg group, IOP increased by 1.7 mm Hg (15%). CONCLUSIONS: Intraocular pressure reduction was proportional to preoperative IOP; the highest preoperative IOPs decreased the most and the lowest increased slightly. One‐year IOP reductions were sustained for 10 years and were similar in patients of all ages. The IOP reductions were similar to previously reported reductions in nonglaucomatous eyes, indicating that the aging crystalline lens may be a major cause of ocular hypertension and glaucoma and that phacoemulsification with IOL implantation may help prevent and treat adult glaucoma.

Canaloplasty: Circumferential viscodilation and tensioning of Schlemm canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults

PURPOSE: To evaluate 2‐year postsurgical safety and efficacy of canaloplasty (circumferential viscodilation and tensioning of the inner wall of Schlemm canal) to treat open‐angle glaucoma (OAG). SETTING: Multicenter surgical sites. METHODS: This international prospective study comprised adult OAG patients having glaucoma surgery or combined glaucoma–cataract surgery. Qualifying preoperative intraocular pressure (IOP) was at least 16 mm Hg and historical IOP, at least 21 mm Hg. The full circumference of the canal was viscodilated and a trabecular tensioning suture placed with a microcatheter. Primary outcome measures included IOP and glaucoma medication use. RESULTS: At 24 months, all 127 eyes (127 patients) had a mean IOP of 16.0 mm Hg ± 4.2 (SD) and mean glaucoma medication use of 0.5 ± 0.8 (baseline values 23.6 ± 4.8 mm Hg and 1.9 ± 0.8 medications). Eyes with canaloplasty alone had a mean IOP of 16.3 ± 3.7 mm Hg and 0.6 ± 0.8 medications (baseline values 23.2 ± 4.0 mm Hg and 2.0 ± 0.8 medications). Eyes with combined glaucoma–cataract surgery had a mean IOP of 13.4 ± 4.0 mm Hg and 0.2 ± 0.4 medications (baseline values 23.1 ± 5.5 mm Hg and 1.7 ± 1.0 medications). The IOP and medication use results at all time points were statistically significant versus baseline (P <.001). The late postoperative follow‐up identified 3 patients with elevated IOP. No other serious ocular or nonocular complications were reported. CONCLUSION: Canaloplasty was safe and effective in reducing IOP in adult patients with OAG.

Canaloplasty: Three-year results of circumferential viscodilation and tensioning of Schlemm canal using a microcatheter to treat open-angle glaucoma

PURPOSE: To report 3‐year results of the safety and efficacy of canaloplasty, a procedure involving circumferential viscodilation and tensioning of the inner wall of Schlemm canal to treat open‐angle glaucoma. SETTING: Multicenter surgical sites. DESIGN: Nonrandomized multicenter clinical trial. METHODS: This study comprised adult open‐angle glaucoma patients having canaloplasty or combined cataract–canaloplasty surgery. Qualifying preoperative intraocular pressures (IOPs) were at least 16 mm Hg with historical IOPs of at least 21 mm Hg. A flexible microcatheter was used to viscodilate the full circumference of the canal and to place a trabecular tensioning suture. Primary outcome measures included IOP, glaucoma medication use, and adverse events. RESULTS: Three years postoperatively, all study eyes (n = 157) had a mean IOP of 15.2 mm Hg ± 3.5 (SD) and mean glaucoma medication use of 0.8 ± 0.9 compared with a baseline IOP of 23.8 ± 5.0 mm Hg on 1.8 ± 0.9 medications. Eyes with combined cataract–canaloplasty surgery had a mean IOP of 13.6 ± 3.6 mm Hg on 0.3 ± 0.5 medications compared with a baseline IOP of 23.5 ± 5.2 mm Hg on 1.5 ± 1.0 medications. Intraocular pressure and medication use results in all eyes were significantly decreased from baseline at every time point (P<.001). Late postoperative complications included cataract (12.7%), transient IOP elevation (6.4%), and partial suture extrusion through the trabecular meshwork (0.6%). CONCLUSION: Canaloplasty led to a significant and sustained IOP reduction in adult patients with open‐angle glaucoma and had an excellent short‐ and long‐term postoperative safety profile. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

A Randomized Trial of a Schlemm's Canal Microstent with Phacoemulsification for Reducing Intraocular Pressure in Open-Angle Glaucoma

PURPOSE To assess the safety and effectiveness of the Hydrus Microstent (Ivantis, Inc, Irvine, CA) with concurrent cataract surgery (CS) for reducing intraocular pressure (IOP) in open-angle glaucoma (OAG). DESIGN Prospective, multicenter, randomized, single-masked, controlled clinical trial. PARTICIPANTS One hundred eyes from 100 patients 21 to 80 years of age with OAG and cataract with IOP of 24 mmHg or less with 4 or fewer hypotensive medications and a washed-out diurnal IOP (DIOP) of 21 to 36 mmHg. METHODS On the day of surgery, patients were randomized 1:1 to undergo CS with the microstent or CS alone. Postoperative follow-up was at 1 day, 1 week, and 1, 3, 6, 12, 18, and 24 months. Washout of hypotensive medications was repeated at 12 and 24 months. MAIN OUTCOME MEASURES Response to treatment was defined as a 20% or more decrease in washed out DIOP at 12 and 24 months of follow-up compared with baseline. Mean DIOP at 12 and 24 months, the proportion of subjects requiring medications at follow-up, and the mean number of medications were analyzed. Safety measures included change in visual acuity, slit-lamp observations, and adverse events. RESULTS The proportion of patients with a 20% reduction in washed out DIOP was significantly higher in the Hydrus plus CS group at 24 months compared with the CS group (80% vs. 46%; P = 0.0008). Washed out mean DIOP in the Hydrus plus CS group was significantly lower at 24 months compared with the CS group (16.9±3.3 mmHg vs. 19.2±4.7 mmHg; P = 0.0093), and the proportion of patients using no hypotensive medications was significantly higher at 24 months in the Hydrus plus CS group (73% vs. 38%; P = 0.0008). There were no differences in follow-up visual acuity between groups. The only notable device-related adverse event was focal peripheral anterior synechiae (1-2 mm in length). Otherwise, adverse event frequency was similar in the 2 groups. CONCLUSIONS Intraocular pressure was clinically and statistically significantly lower at 2 years in the Hydrus plus CS group compared with the CS alone group, with no differences in safety.

A novel Schlemm's Canal scaffold increases outflow facility in a human anterior segment perfusion model.

PURPOSE An intracanalicular scaffold (Hydrus microstent) designed to reduce intraocular pressure as a glaucoma treatment was tested in human anterior segments to determine changes in outflow facility (C). METHODS Human eyes with no history of ocular disease or surgeries were perfused within 49 hours of death. The anterior segments were isolated and connected to a perfusion system. Flow rates were measured at pressures of 10, 20, 30, and 40 mm Hg. The scaffold was inserted into Schlemms canal of the experimental eye, while a control eye underwent a sham procedure. Flow rate measurements were repeated at the four pressure levels. Individual C values were computed by dividing the flow rate by its corresponding pressure, and by averaging the four individual C measurements. The change in C between control and experimental eyes was assessed by the ratio of the baseline and second C measurement. In two eyes, the placement of the scaffold was evaluated histologically. RESULTS After scaffold implantation in the experimental eyes, the average C increased significantly from baseline (n = 9, P < 0.05). Ratios of C at all pressure levels, except for 10 mm Hg, were significantly higher in experimental eyes (n = 9) than control eyes (P < 0.05, n = 7). Histologically, the scaffold dilated Schlemms canal with no visible damage to the trabecular meshwork. CONCLUSIONS The Hydrus Microstent provided an effective way to increase outflow facility in human eyes ex vivo.

Postoperative Complications in the Ahmed Baerveldt Comparison Study During Five Years of Follow-up

PURPOSE To compare the late complications in the Ahmed Baerveldt Comparison Study during 5 years of follow-up. DESIGN Multicenter, prospective randomized clinical trial. METHODS setting: Sixteen international clinical centers. STUDY POPULATION Two hundred seventy-six subjects aged 18-85 years with previous intraocular surgery or refractory glaucoma with intraocular pressure of >18 mm Hg. INTERVENTIONS Ahmed Glaucoma Valve FP7 or Baerveldt Glaucoma Implant BG 101-350. MAIN OUTCOME MEASURES Late postoperative complications (beyond 3 months), reoperations for complications, and decreased vision from complications. RESULTS Late complications developed in 56 subjects (46.8 ± 4.8 5-year cumulative % ± SE) in the Ahmed Glaucoma Valve group and 67 (56.3 ± 4.7 5-year cumulative % ± SE) in the Baerveldt Glaucoma Implant group (P = .082). The cumulative rates of serious complications were 15.9% and 24.7% in the Ahmed Glaucoma Valve and Baerveldt Glaucoma Implant groups, respectively (P = .034), although this was largely driven by subjects who had tube occlusions in the 2 groups (0.8% in the Ahmed Glaucoma Valve group and 5.7% in the Baerveldt Glaucoma Implant group, P = .037). Both groups had a relatively high incidence of persistent diplopia (12%) and corneal edema (20%), although half of the corneal edema cases were likely due to pre-existing causes other than the aqueous shunt. The incidence of tube erosion was 1% and 3% in the Ahmed Glaucoma Valve and Baerveldt Glaucoma Implant groups, respectively (P = .04). CONCLUSIONS Long-term rates of vision-threatening complications and complications resulting in reoperation were higher in the Baerveldt Glaucoma Implant than in the Ahmed Glaucoma Valve group over 5 years of follow-up.

A Novel 8-mm Schlemm's Canal Scaffold Reduces Outflow Resistance in a Human Anterior Segment Perfusion Model

PURPOSE To study the effect on outflow facility and outflow resistance of a nitinol microstent implanted into Schlemms canal. METHODS Using a constant pressure perfusion method, outflow facility and outflow resistance were measured in 26 pairs of dissected anterior segments from donated human eyes. Measurements were made at perfusion pressures of 10, 20, 30 and 40 mm Hg. The Hydrus Microstent was placed in Schlemms canal of one eye and the contralateral eye underwent a sham procedure. Outflow facility and outflow resistance were measured again after the microstent implantation or sham procedure. RESULTS The Hydrus Microstent significantly increased outflow facility from 0.33 ± 0.17 μL/min/mm Hg to 0.52 ± 0.19 μL/min/mm Hg (P < 0.001). Outflow resistance was significantly reduced from 4.38 ± 3.03 mm Hg/μL/min at baseline to 2.34 ± 1.04 mm Hg/μL/min (P < 0.001) with the microstent. There was a linear correlation between outflow resistance at baseline and decrease in outflow resistance with the microstent (R(2) = 0.89, P < 0.0001). CONCLUSIONS The increase in outflow facility and decrease in resistance supports the potential use of the Hydrus Microstent as a surgical option to reduce intraocular pressure (IOP). The IOP-lowering effect may be higher in eyes with higher outflow resistance (and IOP) as compared with eyes with lower outflow resistance (and IOP).