The VISCO360 device (Sight Sciences, Menlo Park, California) allows for catheterization and viscodilation of Schlemm’s canal. Similar to the TRAB360 device, it is a single-use, single-handed device with a sharp distal tip that is used to pierce the trabecular meshwork and a microcatheter is then advanced through 180 degrees of Schlemm’s canal. A predetermined amount of viscoelastic fluid is then injected into Schlemm’s canal and the distal collector channels. The procedure is then repeated for the remaining 180 degree of Schlemm’s canal. The procedure allows for dilation without tissue destruction of the natural drainage system.
The OMNI System (Sight Science, Menlo Park, California) is the same hand piece used for VISCO360 and combines the VISCO360 and TRAB360 procedures. After the surgeon performs viscodilation, the microcatheter is again introduced into Schlemm’s canal and a trabeculotomy is performed to achieve both viscodilation and trabeculotomy in one procedure.
The Visco 360/OMNI System is indicated for the treatment of open angle glaucoma and ocular hypertension. It can be performed as a stand-alone procedure or in combination with cataract surgery. It can be performed in patients who are phakic, pseudophakic or aphakic.
A study by Ondrejka and Korber evaluated the effectiveness of the VISCO360 viscosurgical system for the treatment of mild to moderate primary open angle glaucoma.[1] The study included 106 eyes from 71 patients and divided patients into two groups based on baseline IOP: eyes in group 1 had baseline IOP ≥18 mmHg and group 2 eyes had baseline IOP<18 mmHg. Both groups underwent canal viscodilation with or without cataract extraction. Effectiveness was measured by both amount of IOP reduction as well as reduction in IOP-lowering topical medications at 12 months post-operatively. Of the 72 eyes in group 1, 11 underwent VISCO360 alone and 61 underwent VISCO360 with cataract extraction. At 12 months post-operatively, there was a significant reduction in IOP from a baseline of 24.6±7.1 mmHg to 14.6±2.8 mmHg with an average reduction in IOP of 41% across all eyes. Additionally, 87% of eyes in group 1 achieved ≥20% reduction in IOP from baseline. There was also a significant reduction in IOP lowering drops in group 1 eyes from 2.1±1 to 0.2±0.6 and 85% of eyes required no medications to maintain pre-operative IOP or lower. Of the 34 eyes in group 2, 33 underwent VISCO360 with cataract extraction and only 1 underwent stand-alone VISCO360. Eyes in groups 2 had a mean baseline IOP of 14.9±1.8 mmHg and a post-operative mean IOP of 13.6±2.3 mmHg with no significant difference between the two time points. There was a significant reduction in medications at 12 months from 1.8±0.9 to 0.2±0.6 post-operatively. Further, 88% of eyes in groups 2 were off all IOP lowering drops at 12 months with IOP at baseline. In both groups, there was an excellent safety profile with only 14 eyes experiencing a hyphema, most of which were sub-millimeter in size. There were no subsequent surgical interventions related to the VISCO360.
The advent of microinvasive glaucoma surgery has allowed for improved management of patients with mild to moderate glaucoma. As surgeon experience expands and the number of MIGS approaches grows, these procedures may even be utilized in more severe cases and across a wide range of clinical scenarios. MIGS procedures are an especially useful treatment option in patients with poor medication tolerance, poor compliance and patients who need more IOP-lowering than drops or laser trabeculoplasty can provide. MIGS can be easily incorporated into routine phacoemulsification surgery and can be used in patients who are well-controlled on drops but who desire drop independence. The field of MIGS has expanded rapidly in the last decade adding to the glaucoma surgeons’ armamentarium and their ability to tailor surgical approaches to each specific patient. Future devices and surgical approaches will continue to be developed in the coming years.
[1] Ondrejka S and Korber N. 360o ab-interno Schlemm’s canal viscodilation in primary open angle glaucoma. Clinical Ophthalmology 2019; 13: 1235-1246.
