Glaucoma and Cataract Surgery
First, the good news: It is likely that cataract surgery will make you see better even if you have glaucoma.
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Now, the even better news: Cataract surgery alone usually lowers the pressure in the eye. The amount is hard to predict, but often a reduction of up to 5 mm Hg occurs. You may be able to lower pressure further by adding MIGS (Minimally Invasive Glaucoma Surgery) to your procedure.
MIGS is a catch-all term for a variety of glaucoma devices and procedures that can be added on to your cataract surgery. MIGS may reduce the pressure in the eye by about 2-8 mm Hg beyond what cataract surgery typically achieves. MIGS is not as powerful as trabeculectomy, but is less invasive and not associated with as many short and long-term complications.
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About half of United States cataract surgeons have the training to add MIGS to their cataract procedure when appropriate. MIGS procedures have grown rapidly in the last year because of recent FDA approval of several MIGS devices, including Istent, Hydrus, and Xen.
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How does MIGS work?
See the drawing below. The trabecular meshwork circles the outer edge of the iris. Fluid passes through the trabecular meshwork to exit the eye through Schlemm's canal. Resistance to flow through the trabecular meshwork regulates the pressure inside the eye.
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MIGS procedures lower pressure by reducing resistance at the trabecular meshwork.
Figure 1: Trabecular Meshwork and Schlemm's Canal
MIGS Devices and Procedures
Several different MIGS procedures exist. Their common goal is to reduce the resistance to the flow of fluid from the eye.
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Istent and Hydrus: Istent (Glaucos) and Hydrus (Ivantis) are tiny devices that can be inserted inside the eye, into the trabecular meshwork.
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Xen: Xen (Allergan) is a collagen device that is placed outside the eye. A small wick, about the thickness of a human hair, is inserted into the eye to bypass the trabecular meshwork.
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Trabecutome: This procedure strips away the trabecular meshwork membrane.
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The devices above are listed because they are FDA approved and the most commonly offered in the United States. MIGS devices and procedures will continue to evolve in the coming years.
MIGS- Yes or No?
Is MIGS something you want to add to your cataract surgery? Here are some reasons you might want to consider adding MIGS:
- You have mild to moderate glaucoma
- Your pressure is too high on your current medications
- You want to reduce or eliminate glaucoma eyedrops if possible
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If this sounds like you, ask your surgeon about adding MIGS to your cataract surgery. Adding MIGS will not affect your options regarding astigmatism correction, presbyopia correction, and custom refractive design.