Combined Viscodilation of Schlemm's Canal and Collector Channels and 360° Ab-Interno Trabeculotomy for Congenital Glaucoma Associated with Sturge-Weber Syndrome

Controversies in Pediatric Angle Surgery and Secondary Surgical Treatment

Pediatric glaucoma is a constellation of challenging ophthalmic conditions that, left untreated, can result in irreversible vision loss. The mainstay of treatment for primary congenital glaucoma and select secondary glaucoma subtypes is angle surgery, either trabeculotomy or goniotomy. More recently, MIGS devices have been utilized to enhance the efficacy of these procedures. Despite the high success rates of these primary surgical options, refractory cases are challenging to manage. There is no consensus on the next step of treatment following primary angle surgery. Glaucoma drainage devices and trabeculectomies have been the traditional options, with laser treatment reserved for more severe cases. The benefits and disadvantages of each of these options are discussed.

Ab-interno Trabeculotomy Procedures: A Review

Purpose

To discuss the safety and efficacy of various forms of ab-interno trabeculotomy procedures.

Methods

A comprehensive search in PubMed and Google Scholar was done using the keywords "glaucoma", "microinvasive glaucoma surgery", "complications", "goniotomy", and "trabeculotomy". Publications discussing ab-interno trabeculotomy procedures were selected; furthermore, the relevant references in these articles were gathered and the search was updated during the article preparation. Since gonioscopy-assisted transluminal trabeculotomy was first introduced in 2014, we had no time restriction.

Results

Ab-interno trabeculotomy procedures, as a type of minimally invasive glaucoma surgeries, facilitate the natural trabecular outflow and lower the intraocular pressure (IOP) while preserving the conjunctiva for possible future glaucoma surgeries. It can be done alone or in combination with cataract surgery and effectively lowers the IOP and the number of antiglaucoma medications in various forms of glaucoma.

Conclusion

By appropriate patient selection, ab-interno trabeculotomy could be selected as a safe and effective procedure in the management of various forms of glaucoma either as an isolated procedure or in combination with cataract extraction.

Minimally invasive glaucoma surgery in childhood glaucoma

PURPOSE OF REVIEW

Minimally invasive glaucoma surgery (MIGS) has been shown to be safe and effective in treatment of mild to moderate glaucoma in adults, but reports in childhood glaucoma are limited. We review the available data concerning MIGS and discuss its potential role in childhood glaucoma management.

RECENT FINDINGS

Ab interno counterparts to circumferential ab externo trabeculotomy such as gonioscopy-assisted transluminal trabeculotomy (GATT) and Trab360 show promise in treatment of primary glaucomas as reported in a few retrospective case series. Kahook Dual Blade (KDB) and Trabectome have demonstrated mixed results in few published case reports in children. Small case series and reports suggest that the Xen gel stent can be a safer alternative to traditional filtration surgery, though data on long-term implant and bleb stability are unavailable. Newer devices are being investigated and early results are encouraging.

SUMMARY

GATT and Trab360 seem to be safe, effective methods of achieving circumferential trabeculotomy in childhood glaucoma. KDB, Trabectome, and Xen gel stent have shown some success in selected cases with short-term follow-up. Surgeons must determine the risks and benefits of MIGS over more established methods of intraocular pressure reduction for each individual child. Further research is needed to validate initial findings regarding MIGS in childhood glaucoma.

Sturge-Weber Syndrome and Glaucoma

Sturge-Weber syndrome (SWS) is a neurocutaneous syndrome characterized by capillary venous malformations in the skin, eye, and brain with the occurrence of angiomas of the face, choroid, and leptomeninges. The characteristics signs include facial port-wine birth mark, glaucoma, choroidal hemangioma with brain malformations, and cognitive abnormalities. In this article, we have documented the case report of a 24-year-old male with SWS presenting with glaucoma.

Standalone Trabeculotomy and Viscodilation of Schlemm's Canal and Collector Channels in Open-Angle Glaucoma Using the OMNI Surgical System: 24-Month Outcomes

Purpose

Intraocular pressure (IOP), medication outcomes at 24 months following trabeculotomy/viscodilation using the OMNI® surgical system as a standalone procedure in medically uncontrolled mild-moderate open-angle glaucoma (OAG).

Setting

Surgical center (Duesseldorf, Germany).

Design

Retrospective analysis. IOP and medication data were collected before surgery and through 24 months. Safety data included adverse events and the need for additional surgery.

Methods

Pre-op medication washout. Goldmann tonometry. Number of medications and adverse events (AE) at each time point. Primary outcomes: changes in IOP and medications. Two-sided paired t-tests compare values at each follow-up with baseline, significance p = 0.05. Secondary outcomes: proportion of eyes with IOP reduction of ≥20%, on fewer medications, and medication-free at each time point.

Results

This analysis included data from 38 eyes of 27 subjects. Mean (standard deviation) baseline IOP was 24.6 (3.0) mmHg and through 24 months ranged from 12.6 to 14.9 mmHg (p < 0.0001), representing reductions of 10.0-12.0 mmHg. Mean medications were 1.9 (baseline) and through 24 months ranged from 0.0 to 0.5 (70.6-100% reduction) (p < 0.0001). At Month 24, mean IOP was 14.9 mmHg (-10.0 mmHg), and 100% of eyes achieved IOP reduction >20% from baseline; mean medication use was 0.5 (-1.4 medications, p < 0.0001), 84.6% of eyes using >1 fewer medication, and 57.7% were medication-free. The most common adverse event was intraoperative hyphema (44.7%); all resolved spontaneously. There were two secondary procedures for IOP control.

Conclusion

The OMNI surgical system provides clinically relevant and statistically significant reductions in both IOP and medications with an excellent safety profile and should be considered in phakic or pseudophakic eyes with mild-moderate OAG requiring IOP or medication reduction, or both.

12-month interim results of a prospective study of patients with mild to moderate open-angle glaucoma undergoing combined viscodilation of Schlemm's canal and collector channels and 360° trabeculotomy as a standalone procedure or combined with cataract surgery

PURPOSE

To characterize clinical outcomes of combined viscodilation of Schlemm's canal and collector channels and 360° trabeculotomy as a standalone procedure or combined with cataract surgery in eyes with mild to moderate open-angle glaucoma (OAG).

METHODS

In this prospective case series, the OMNI glaucoma surgical platform (Sight Sciences, Menlo Park, CA) was utilized to perform the procedure either combined with phacoemulsification or as a standalone procedure. Changes from baseline in intraocular pressure (IOP) and IOP-lowering medications were evaluated through the first 12 months of a planned 24-month follow-up period.

RESULTS

Among 17 eyes of 15 subjects, mean IOP was reduced from 20.4 mmHg to 12.7-13.7 mmHg through 12 months of follow-up (p < 0.001 at every time point) and mean medications reduced from 2.5 to 0.1-0.6 (p < 0.001 at every time point). IOP reductions in eyes undergoing standalone surgery were approximately 2-4 mmHg greater at each time point compared to eyes undergoing surgery combined with phacoemulsification; this may be related to a higher baseline IOP in the former eyes (22.1 vs 18.5 mmHg). Six eyes developed hyphema, of which three required washout for elevated IOP on the first postoperative day; six additional eyes had IOP elevations that resolved with medical management.

CONCLUSION

Viscodilation of Schlemm's canal and collector channels paired with ab interno trabeculotomy performed with a single integrated instrument (OMNI), whether as standalone or combined with phacoemulsification, effectively lowers both IOP and the need for IOP-lowering medications through 12 months of follow-up.