The Kahook Dual Blade (KDB) is a surgical device used in Minimally Invasive Glaucoma Surgery (MIGS). Glaucoma damages the optic nerve, which transmits visual information to the brain, and is often caused by an increase in intraocular pressure (IOP). The main objective of glaucoma treatments like the KDB procedure is to lower this pressure to prevent vision loss.
How the Kahook Dual Blade Works
The eye continuously produces a fluid called aqueous humor, which circulates in the front part of the eye. In a healthy eye, this fluid drains through a spongy tissue area called the trabecular meshwork into a channel known as Schlemm’s canal. In open-angle glaucoma, this drainage system becomes less efficient, causing fluid to build up and increase IOP.
The KDB procedure is a type of goniotomy that directly addresses this blockage. The Kahook Dual Blade is a single-use ophthalmic blade with a sharp tip designed to pierce the trabecular meshwork. It also features a unique ramp that gently lifts the tissue, allowing the dual blades to make precise, parallel incisions to excise a segment of the diseased tissue.
This removal of tissue unroofs the inner wall of Schlemm’s canal, creating a direct pathway for the aqueous humor to exit the eye. By restoring a more natural outflow, the procedure lowers intraocular pressure. The KDB can also be performed as a standalone surgery.
Ideal Candidates for the KDB Procedure
The KDB procedure is recommended for individuals with mild-to-moderate primary open-angle glaucoma. It is a suitable option for patients concurrently undergoing cataract surgery. Combining the two surgeries is efficient, as both can be performed through the same micro-incision in a single session, which minimizes separate recovery periods.
Another group that benefits includes patients who experience significant side effects from prescribed glaucoma eye drops. Some individuals find the daily regimen difficult to adhere to or find the long-term cost to be a burden. The KDB procedure offers a surgical alternative that can reduce or eliminate dependence on these topical treatments.
However, not everyone with glaucoma is a suitable candidate. It is not recommended for individuals with severe or advanced-stage glaucoma, as they may require more aggressive pressure-lowering interventions. Patients with other types of glaucoma, such as angle-closure glaucoma, or those with significant scarring of the eye’s drainage angle from past surgeries or trauma are also not ideal candidates.
Recovery and Expected Outcomes
Following the KDB procedure, patients can expect a straightforward recovery. It is common to experience blurry vision and a mild, scratchy sensation in the eye for the first few days, but these symptoms are temporary. The surgeon will prescribe anti-inflammatory and antibiotic eye drops for several weeks to prevent infection and control inflammation.
During the initial recovery phase, patients are advised to follow specific activity restrictions. These limitations include avoiding heavy lifting, strenuous exercise, and swimming for a few weeks. It is also important to refrain from rubbing the eye, as this can interfere with the healing process. Most people can resume normal daily activities, such as reading and watching television, relatively quickly.
The primary outcome of the KDB procedure is a sustained reduction in intraocular pressure. A secondary benefit is the potential reduction in the need for glaucoma medications. Many patients find they can discontinue one or more of their glaucoma eye drops. The final outcome can take about six to eight weeks to be fully realized, with studies showing positive results for pressure reduction or a decrease in medication burden.
Potential Risks and Complications
Like any surgery, the KDB procedure carries potential risks. The most common complication is a hyphema, a small amount of blood in the anterior chamber of the eye. This is a mild issue that occurs as the new drainage channel is created and resolves on its own without intervention within a week.
Less frequently, patients may experience a temporary spike in intraocular pressure immediately following the surgery. Surgeons take preventative measures, sometimes prescribing oral medication for a few days to manage this. Postoperative inflammation beyond the expected amount can also occur, which is managed with the prescribed anti-inflammatory eye drops.
More significant complications are rare but include the risk of infection, which is a possibility with any intraocular surgery, or the procedure failing to lower eye pressure to the target level. A thorough discussion with the surgeon is necessary to fully understand the benefits and risks, allowing for an informed decision.