Treatment and Technology

Treatment and Technology

Reduction of intraocular pressure (IOP) is the only proven treatment for glaucoma.9-10 The IOP needed to stop vision loss depends on how the optic nerve of each individual responds to increases in pressure.11-17

The most common treatments for glaucoma are topical, IOP-lowering eye drops, and laser treatments. However, increased understanding of the eye and IOP have led to a new technology that offers a potential solution for patients whose needs are not being met by current glaucoma treatment options.

Pharmacotherapy

There are several classes of topical IOP treatments, some of which have been available for centuries (Pilocarpine drops were introduced in 1875).20 Most topical eye drops aim to decrease IOP by reducing aqueous humor production and/or by increasing drainage of aqueous humor through one or both of the outflow pathways.20 Studies show these drops can reduce IOP by 15-39% for some patients; however, dosing regimens can be complex and some patients experience substantial local and systemic side effects.20

Laser treatments

Laser treatments may be offered in addition to, or instead of pharmacotherapies. Laser treatment is applied either to the ciliary body (where aqueous humor is produced) or to the trabecular meshwork (through which aqueous humor drains from the eye).20

Advanced glaucoma surgeries

When pharmacological and laser treatments are ineffective, patients may require glaucoma surgery. There are two main kinds of conventional glaucoma surgeries: trabeculectomies and implantation of glaucoma drainage devices (GDDs).

Trabeculectomy

Studies have shown that these surgeries may not be effective in the long term. The Tube Verses Trabeculectomy (TVT) Study reported trabeculectomy failures of 40-60% within 3 years after the surgery, and 50-70% failed within 5 years after the surgery. In this study, failure was defined either as 1) having an IOP that was not reduced by 20% below baseline or 2) having IOP > 14 mmHg.21

Unsustainable and unpredictable IOP lowering is mainly due to the fact that these devices drain aqueous humor in between tissues where scarring can occur. Specifically, trabeculectomies aim to create a little reservoir for drainage called a bleb. This bleb is created in the space under the conjunctiva. Bleb scarring is a major issue and requires close management. Even with the use of anti-scarring agents like mitomyocin C, trabeculectomies can lead to increased incidence of surgical failure and other complications.

Glaucoma Drainage Devices (GDDs)

GDDs, like the Ahmed and Baerveldt Implants, have been used as an alternative surgical approaches to reduce IOP by creating a passageway for aqueous humor to leave the eye through a tube attached to a large plate. This passageway guides aqueous humor from the anterior chamber, to a space under the conjunctiva. Similar to trabeculectomies, anti-scarring agents are used to avoid additional surgical complications. However, GDDs may lead to erosion of the conjunctiva where the device may be forced out of place. Efforts to reposition or remove the GDD may lead to additional complications 22,23, they are therefore commonly not removed when they fail and a new GDD may need to be placed elsewhere in the eye. Because of the size of the drainage plate, there is a limit to the total number that can be placed during the course of the patient’s life.

When trabeculectomies and GDDs fail, patients are left with few options. A last resort for patients may include procedures called trans-scleral laser cyclophotocoagulation (TS-CPC) and endocyclophotocoagulation (ECP). These are invasive procedures that damage parts of the ciliary body to reduce the production of aqueous humor.24,25 Patients who undergo these procedures are at risk for a condition called hypotony, or very low IOP. Hypotony can lead to severe complications associated with the cornea, retina, and other posterior eye structures, and may lead to permanent loss of vision.

Sollevio

Alievio is developing a next generation glaucoma treatment option that will allow for noninvasive titration of postoperative IOP based on the needs of the individual patient. This adjustability is made possible by Sollevio’s mechanism of aqueous flow resistance, which is located within a soft outlet tube that lies externally underneath the eyelid. Physicians can further adjust IOP postoperatively, based on clinical findings, by simply modifying the device outlet tube during an in-office visit, under local anesthesia.

Smaller reservoir:

Unlike other GDDs, Sollevio does not require a large plate to maximize drainage because it drains aqueous humor externally. Its smaller size also allows for easier revision surgery and removal, if necessary.

Comfort:

Sollevio’s outlet tube is as soft as a contact lens and lies underneath the eyelid, which is the least sensitive area on the surface.

How does Sollevio differ from existing Glaucoma Drainage Devices (GDDs) and Trabeculectomy?

Sollevio differs from existing GDDs such as Ahmedvalves and Baerveldt shunts, and trabeculectomy, by its improved design and novel aqueous drainage site. Key features of Sollevio offer improved patient outcomes, and also include the following:

  • No bleb, minimal fibrous capsule:

    A bleb is a raised area of conjunctiva underneath which aqueous humor fluid accumulates following trabeculectomy. Blebs are a major source of post-operative complications and surgical re-interventions. Sollevio avoids bleb-related complications as it drains aqueous externally.  There is minimal fibrous capsule reaction around Sollevio, with reduced risk of failure compared with the heavy fibrous capsules observed in Ahmed valves and Baerveldt tubes.

  • Noninvasive postoperative adjustment:

    Sollevio’s outlet tube has an aqueous flow resistance mechanism that can be adjusted to reach targeted IOP based on the needs of the patient. The physician can easily access the outlet tube by simply lifting the eyelid.

  • A barrier against infection:

    Sollevio includes a micropore filter to eliminate the risk of infection.

Sollevio meets a significant unmet need among refractory glaucoma patients who want effective, IOP-reducing treatment without the risks and complications associated with conventional incisional glaucoma surgeries. The innovative technology behind Sollevio’s design offers physicians the flexibility to adjust IOP postoperatively to each patient’s individual needs. These adjustments take place noninvasively, within the comfort of the physician’s office, and require only local anesthesia.

References
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  2. Nouri-Mahdavi K, Hoffman D, Gaasterland D, et al. Prediction of visual field progression in glaucoma. Invest Ophthalmol Vis Sci. 2004;45(12):4346-51.
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