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Minimally invasive (also known as micro-invasive or micro-bypass) glaucoma surgery refers to a class of surgical treatment used to manage mild-to-moderate cases of primary open-angle glaucoma.
This is the most common type of glaucoma and results when the trabecular meshwork that drains aqueous fluid from the front of the eye is not working properly. As a result, pressure in the eye (also called intraocular pressure or IOP) increases and pushes on the optic nerve. Over time, damage to the nerve fibres results in peripheral (side) and eventually central vision loss.
MIGS procedures involve placing tiny medical devices in the eye to improve fluid outflow through the trabecular meshwork. The resultant decline in IOP reduces stress on the optic nerve and prevents further damage.
MIGS is occasionally used to treat some secondary glaucomas, such as pseudoexfoliation glaucoma or pigmentary glaucoma.
Three implants are approved for use in Australia:
MIGS is typically offered after conventional treatments (medicated eye drops, laser therapy) have failed to achieve a satisfactory reduction in IOP. This type of surgery has a good safety profile and can delay the need for more invasive surgical procedures (trabeculectomy, drainage devices) in some people.
Previously, patients could only qualify for a Medicare rebate for MIGS when it was combined with cataract surgery. However, as of 1 May 2020, a standalone MIGS rebate (not performed in conjunction with another surgery) is available for patients with glaucoma who fail or are not eligible for conventional treatment with drops or laser therapy.4
Eligible patients can receive the Medicare rebate for MIGS when it is performed by an ophthalmologist with recognised training in these procedures.
While the mechanism varies, all treatment options aim to manage glaucoma by reducing IOP.
Combined MIGS and cataract surgery typically takes 30–40 minutes operating time, while standalone MIGS may only take 5–10 minutes. Allowing for admission, preparation and recovery time, you should expect to be in the day surgery for around 2–3 hours.
MIGS is performed under a local anaesthetic. You may feel some slight pressure on your eye during the operation, but there won’t be any pain.
No, stents cannot be felt once placed in the eye.
Recovery is rapid and typically no longer than the recovery period for cataract surgery (approximately 2–4 weeks). You will be prescribed medicated eye drops after the surgery to treat any swelling and inflammation. Your doctor will advise you on how often and how long to use the drops. You should be able to resume normal activities after 2 weeks.
The MIGS devices that are currently approved for use in Australia are safe. However, as with all surgical procedures, there are potential risks.
Minor postoperative complications include:
An uncommon but serious complication that can occur after MIGS is endophthalmitis (infection within the eye). If left untreated, this can lead to irreversible vision loss.
After a MIGS procedure, you will temporarily stop all your regular glaucoma medication so that your eye pressure can be reassessed and monitored. Many patients find that they no longer need glaucoma medication or can reduce the number of drops they take, but this is not guaranteed. Some patients may also need to restart eye drops or laser treatment in the future if their eye pressure goes back up.
When deciding the best course of treatment, your ophthalmologist will take into account your lifestyle, pre-existing eye conditions, type and severity of glaucoma and initial eye pressure. Regardless of whether medication, laser therapy or surgery is recommended, it’s important that you don’t stop treatment without speaking to your ophthalmologist first. Glaucoma requires long-term management by an ophthalmologist to keep your eye pressure controlled and prevent or minimise vision loss.
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