Frolov Mikhail, Dushina Galina Ab externo Schlemm’s canal surgery in management of open angle glaucoma Kumar Vinod Frolov Mikhail, Dushina Galina Ophthalmic unit of Skhodnya city hospital, Moscow province, Russian Federation; Department of ophthalmology, Medical Institute of People’s friendship university of Russia, Moscow Financial disclosure – People’s friendship university of Russia is the patent holder of the device ESCRS-2015 Barcelona

Introduction Kumar’s 1st generation Schlemm’s canal expander (SCE) Length - 5-6mm long; outer diameter - .3mm; inner diameter - .2mm Schematic representation and actual size of Kumar’s 1st generation SCE reduction in mean IOP by 46% Complete success – 41.7% cases Partial success – 58.3% cases Disadvantages: size not appropriate for all cases implantation required repeated SC dilation Traumatic to SC structures implantation Russian patent of useful model № – 130840 dated 21.02.2013

Kumar’s 2nd generation SCE Device was made from 0.04mm thick medical grade soft vanadium stainless steel wire by winding it on a 0.12 mm thick stainless steel microprobe having curvature as of SC. Measurements: length -3.0 mm; inner lumen diameter - .12mm; outer - .2mm. Natural size of 1st generation SCE Natural size of 2nd generation SCE 2nd generation SCE in comparison to 1 kopek coin Purpose: To evaluate the effectiveness of segmental Schlemm’s canal (SC) distension using Kumar’s 2nd generation stainless steel spiral Schlemm’s canal expander (SCE) in decreasing intraocular pressure (IOP) in patients with open angle glaucoma (OAG).

Methods and material Design: Uncontrolled, non-randomized, interventional case series. Total 13 cases (13 eyes): Male –9 (69.2%), female – 4(30.8%); avg. age: 71.2+/-1.7 yrs. Study period: June 2013 – Feb 2015. Exclusion criteria: Angle closure glaucoma and cases with crowded angle; minimum follow up less than 12 months Main outcome measures: IOP change, complication rate, additional glaucoma medication, need for surgical revision. Criteria for success : Complete success - decrease in IOP >20% or IOP 18 mmHg or less without medication Partial success - decrease in IOP >20% or IOP 18 mmHg or less with medication Failure - cases requiring 2nd surgery A paired t-test was used for analysis. Results were significant when p less than .05

Surgical technique of implantation of 2nd generation SCE

Mean IOP after implantation of 2nd generation SCE SCE-2: at 12 months mean IOP decreased by 44.5+/-12.8% (n=12; 95% CI 37.2-51.7) SCE-1: at 12 months mean IOP decreased by 49.8+/-15.3% (n=10; 95% CI 40.1-52.3)

Mean postoperative IOP after 2nd generation SCE reduction 18mmHg 6mmHg

Mean number of hypotensive medications

Success rate Follow up 6 months 12 months Success SCE-1 SCE-2 P p Complete 72.2% 41.7% 0.004 60% 0,069 Partial 27.8% 58.3% 0.001 40% 0.065 Failure

Results Easy to implant No need for mechanical dilation of canal SCE-1 SCE-2 SCE-2 Observations during surgery: Micro-perforation of TM SCE-2: 15% (2/13) cases SCE-1: 16.7% (3/18) cases Observations in postoperative period: YAG laser trabeculpuncture SCE-2: 25% (3/12) cases SCE-1: 6% (1/18) cases Easy to implant No need for mechanical dilation of canal Early rehabilitation No cases of hypotony, endophthalmitis, or shallow AC Not a single case of inflammation at insertion site

Kumar’s 3rd generation Schlemm’s canal expander Discussion: By reducing the size of the device we got the following advantages of the new model: Insertion of the device into SC became more easier and less traumatic as no mechanical dilation of SC is required. Disadvantages of new model: 1. Length of distended? segment of SC is reduced by 50%, which may be reason for less number of cases with complete success. 2. SC may not be well distended resulting in need of more YAG laser trabeculopuncture in early postoperative period. Conclusions: Though results of SCE-2 insertion in surgical management of OAG show significant reduction in IOP from the baseline and in hypotensive medication(s) use, the reduced size may not be the appropriate one, as it does not distend the SC well enough to ensure high number of complete success cases. Kumar’s 3rd generation Schlemm’s canal expander 5mm in length, inner diameter-.15mm, outer diameter .25mm

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