360° ab-interno Schlemm’s canal viscodilation in primary open-angle glaucoma

Figures & data

Figure 1 VISCO360^® Viscosurgical System. (A) Illustration of the device showing a handpiece with a microcatheter, control wheel for advancing and retracting the microcatheter, viscoelastic reservoir/infusion pump, and a locking mechanism. (B) Schematic of circumferential viscodilation of Schlemm’s canal (SC) through clear corneal incision. VISCO360^® cannula tip creates an opening into SC. A controlled volume of viscoelastic fluid is delivered as the microcatheter is retracted back. VISCO360 Viscosurgical System.

Note: Images are sourced from Sight Sciences, http://sightsciences.com and used with permission.

Figure 2 Ab-interno 360° microcatheterization and viscodilation of Schlemm’s canal (SC) using the VISCO360^® in a human eye. VISCO360^® cannula (indicated by star) was positioned at the desired location in anterior chamber angle through clear corneal incision (A) and an opening into SC was created with the cannula tip (B), the finger wheel was used to gently advance the microcatheter (indicated by arrow) out of the cannula and into SC (C). As the microcatheter was retracted back out of SC and into the cannula, a controlled volume of viscoelastic fluid was delivered thereby dilating SC along its entire length (D).

Table 1 Patient demographics at baseline

Attribute	Value
Subjects (n)	71
Eyes (n)	106
Age (Years) Mean	75.0±7.7
Range	54 to 91
Gender n (%) Male	26/71 (37%)
Female	45/71 (63%)
Study Eye n (%) OD	50/106 (47%)
OS	56/106 (53%)
Lens status n (%) Pseudophakic	12/106 (11.3%)
Phakic	94/106 (89.6%)
Cohorts n (%) Group 1	72/106 (68%)
Group 2	34/106 (32%)
Treatment n (%) VISCO360	12/106 (11.3%)
VISCO360+CE	94/106 (88.7%)

Figure 3 Mean intraocular pressure (IOP) over time in Group 1. Effectiveness seen as a significant drop in mean IOP at postoperative Day 1 which remained similar across all postoperative visits until Month 12. *Statistically significant reduction (P<0.001). Error bars, SD.

Abbreviations: BL, baseline; D, day; M, month; n, number of eyes available for analysis.

Figure 4 Reduction in intraocular pressure (IOP) by ≥20% with same or fewer medications in Group 1. The figure shows the proportion of eyes meeting the outcome measure with no increase in IOP-lowering medications over time.

Abbreviation: N, number of eyes available for analysis.

Figure 5 Mean number of intraocular pressure (IOP)-lowering medications over time in Group 1. *Statistically significant reduction (P<0.001). Error bars, SD.

Abbreviations: BL, baseline; D, day; M, month; n, number of eyes available for analysis.

Figure 6 Proportion of patients who achieved medication independence without an increase in intraocular pressure (IOP) as compared to baseline in Group 1.

Abbreviation: N, number of eyes available for analysis.

Table 2 Effectiveness outcomes in VISCO360-alone subgroup (n=11)

Intraocular pressure (IOP)
Eyes available for analysis (n)	Mean IOP ± SD mmHg	Change from preoperative ± SD mmHg (95% CI)	Proportion of eyes with IOP reduction ≥20%
Preoperative (11/11)	28.8±6.4	N/A	N/A
Day 1 (11/11)	14.0±7.1	−14.8±10.5 (−17.0, −12.6)	9/11 (82%, CI: 48%, 97%)
Month 1 (11/11)	17.5±3.9	−11.4±6.6 (−12.8, −10.0)	9/11 (82%, CI: 48%, 97%)
Month 3 (9/11)	17.2±2.1	−11.6±8.2 (−13.5, −9.6)	8/9 (89%, CI: 52%, 100%)
Month 6 (9/11)	16.6±4.1	−12.0±7.2 (−13.7, −10.3)	6/9 (67%, CI: 30%, 93%)
Month 12 (11/11)	14.5±3.6	−14.3±6.9 (−15.7, −12.8)	9/11 (82%, CI: 48%, 97%)
Eyes available for analysis (n)	Mean number of IOP-lowering medications ± SD	Change from preoperative ± SD (95% CI)	Fewer number of medications than preoperatively, N (%, 95% CI)
Preoperative (11/11)	3.0±1.3	N/A	N/A
Day 1 (11/11)	0.0±0.0	−3.0±1.3 (−3.3, −2.7)	11/11 (100%)
Month 1 (11/11)	0.2±0.4	−2.8±1.4 (−3.1, −2.5)	11/11 (100%)
Month 3 (9/11)	0.6±0.9	−2.3±1.3 (−2.6, −2.0)	9/9 (100%)
Month 6 (9/11)	1.1±1.2	−1.9±1.5 (−2.2, −1.5)	8/9 (89%, CI: 52%, 100%)
Month 12 (11/11)	0.8±1.1	−2.2±1.8 (−2.6, −1.8)	10/11 (91%, CI: 58%, 99%)

Notes: 95% CI=95% confidence interval per binomial distribution. The single standalone case in Group 2 is not included here because of the overall different treatment goals.

Figure 7 Mean intraocular pressure (IOP) over time in Group 2. Effectiveness seen as no change in mean IOP across all postoperative visits up to Month 12 as compared to baseline (P>0.05). Error bars, SD.

Abbreviations: BL, baseline; D, day; M, month; n, number of eyes available for analysis.

Figure 8 Mean number of intraocular pressure (IOP)-lowering medications over time in Group 2. *Statistically significant reduction compared to baseline (P<0.001). Error bars, SD.

Abbreviations: BL, baseline; D, day; M, month; n, number of eyes available for analysis.

Figure 9 Proportion of eyes achieving medication independence without an increase in intraocular pressure (IOP) as compared to baseline in Group 2.

Abbreviation: N, number of eyes available for analysis.

Table 3 Ocular adverse events

Intraoperative events	Number of eyes (%)
VISCO360 Device Deficiency	1 (0.9)
Postoperative events
Hyphema (<1 mm)	11 (10.3)
Hyphema (1–3 mm)	3 (2.8)
Hyphema (3 mm)	0 (0.0)
Fibrin in pupillary plane	1 (0.9)
Intraocular pressure elevation ≥10 mmHg higher than preoperatively*	1 (0.9)
Unrelated ophthalmic surgery	2 (1.8)

Note: *At or beyond 1 month.

Table 4 Comparison of VISCO360 results for Group 1 (baseline-IOP ≥18 mmHg) to iTrack¹¹ and iStent¹⁷ studies

	VISCO360 alone n=11	VISCO360 + CE n=61	All VISCO360 n=72	iTrack alone n=54	iTrack^† + CE n=20	iStent + CE n=117	CE alone n=123
Eyes with follow-up data at each visit, number (%)
Month 3	9 (82%)	57 (93.4%)	66 (93%)	41 (76%)	16 (80%)
Month 6	9 (82%)	52 (85.2%)	61 (85%)	42 (78%)	17 (85%)
Month 12	11 (100%)	60 (98.4%)	71 (99%)	35 (65%)	13 (65%)
Mean intraocular pressure (SD), mmHg (non-washout)
Preoperative	28.8 (6.4)	23.8 (6.9)	24.6 (7.1)	24.1 (3.9)	23.5 (5.4)	18.6 (3.4)	17.9 (3.0)
Month 3	17.2 (2.1)	13.5 (2.9)	14.0 (3.1)	16.7 (5.1)	14.4 (3.3)
Month 6	16.6 (4.1)	13.2 (3.3)	13.7 (3.6)	16.8 (4.0)	12.7 (2.2)
Month 12	14.5 (3.6)	14.6 (2.6)	14.6 (2.8)	16.2 (3.5)	12.8 (3.6)	17.0 (2.8)	17.0 (3.1)
Mean number of anti-glaucoma medications
Preoperative	3.0 (1.3)	1.9 (0.8)	2.1 (1.0)	NR	NR	1.6 (0.8)	1.5 (0.6)
Month 12	0.8 (1.1)	0.1 (0.5)	0.2 (0.6)	NR	NR	0.2 (0.6)	0.4 (0.7)

Notes: †Results are presented for the group of iTrack patients who had successful suture tensioning (n=74) since the authors stratified the results for these patients by iTrack alone and CE+iTrack. NR: not reported. Lewis et al did not report medication data for group of patients with successful suture tensioning. However, for the entire iTrack study cohort (n=94 patients), medication use declined from 1.9±1.0 at baseline to 0.6±0.9 at 12 months. See reference¹¹ for the iTrack study and reference¹⁷ for the iStent study.

Lewis RA, von Wolff K, Tetz M, et al. Canaloplasty: circumferential viscodilation and tensioning of Schlemm’s canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults: interim clinical study analysis. J Cataract Refract Surg. 2007;33(7):1217–1226. doi:10.1016/j.jcrs.2007.03.051

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Craven ER, Katz J, Wells J, Giamporcaro JE, iStent Study Group. Cataract surgery with trabecular micro-bypass stent implantation in patients with mild-moderate open-angle glaucoma and cataract: two-year follow-up. J Cataract Refract Surg. 2012;38(8):1339–1345. doi:10.1016/j.jcrs.2012.03.025

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