iStent inject stents – size demonstration
In a recent study glaucoma patients, who considered themselves to be
compliant with their treatment instructions, were videoed instilling their
drops. Twenty percent did not even get a single drop in their eye while 30
percent contaminated the bottle tip by touching the eye. Poor persistence with
glaucoma medications compounds the problem with studies reporting that less
than 25 percent of patients use their eye drops continuously for 12 months.
Selective laser trabeculoplasty (SLT) is a noninvasive, medication-sparing
therapy that lowers IOP, however its effectiveness generally
decreases over time. This means that repeat treatments are often required
to maintain control of IOP.
Traditional invasive surgical treatments for glaucoma, such as
trabeculectomy and drainage tube surgery, are very effective at lowering
IOP but are associated with considerable downtime for the patient,
disruption of the surface layer of the eye, and life-long risk of possible
serious complications such as leakage from the drainage site, too low IOP,
and sight-threatening infection. For these reasons, invasive glaucoma
surgery is reserved for those with moderate to advanced glaucoma who
have failed to respond to medical and/or laser treatment.
Minimally Invasive Glaucoma Surgery (MIGS) is an evolving area of
glaucoma surgery which aims to provide a safer and less invasive means
of reducing IOP than traditional glaucoma surgery. As it is minimally
invasive, it has little or no effect on the surface layer of the eye. This
has the advantage of preserving the surface layer should more invasive
glaucoma surgery be required in the future. Importantly, unlike traditional
glaucoma surgery, MIGS has a rapid recovery time.
The microtrabecular bypass stent is a MIGS device that is introduced
through the trabecular meshwork in the drainage angle from the inside of
the eye. The stent allows aqueous (the fluid that fills the anterior chamber
of the eye) to flow out of the eye, bypassing the trabecular meshwork
which is the site of outflow resistance in glaucoma. Because MIGS
devices are placed using the same wound created for cataract surgery, the
two procedures are readily combined.
MIGS is suitable for mild to moderate open angle glaucoma or ocular
hypertension. The recent Hydrus II study showed that 73 percent of
patients receiving the Hydrus Microstent in conjunction with cataract
surgery, were medication free at 2 years compared to 38 percent of
patients receiving cataract surgery alone. Clinical studies with the iStent
inject have shown that when combined with cataract surgery, 92 percent
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