What is Minimally Invasive Glaucoma Surgery?
Minimally invasive (or micro-invasive) glaucoma surgery, also known as MIGS, is a collection of surgeries that has been recently developed to minimise some of the complications involved with common glaucoma surgeries, such as trabeculectomies and tube-shunt surgeries.
Glaucoma is an eye condition characterized by damage of the optic nerve, due to increased intraocular pressure (IOP) or internal eye pressure. The increased intraocular pressure is usually caused by accumulation of fluid inside the eye due to its inability to drain. If left untreated, glaucoma can lead to progressive vision loss and ultimately blindness.
MIGS is performed by means of tiny incisions and the use of microscopic devices to decrease the pressure inside the eye to prevent damage to the optic nerve, aiming to eliminate or reduce the necessity of glaucoma eye drops or invasive surgery. MIGS procedures are usually performed during cataract surgery but can also be performed alone if needed.
Indications for Minimally Invasive Glaucoma Surgery
Some indications for minimally invasive glaucoma surgery include:
- People with clinically significant cataracts, as surgery can be done simultaneously
- People with mild to moderate glaucoma
- Failure of conservative treatments, such as eye drops or laser therapy to control glaucoma
- To avoid potential complications of standard glaucoma surgeries
Preparation for Minimally Invasive Glaucoma Surgery
Preoperative preparation for minimally invasive glaucoma surgery will involve the following steps:
- A thorough eye examination is performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
- Depending on your medical history, social history, and age, you may need to undergo tests such as blood work and imaging to help detect any abnormalities that could threaten the safety of the procedure.
- You should refrain from using makeup or lotion around the eyes a few days prior to the surgery.
- You will be asked if you have allergies to medications, anaesthesia or latex.
- You should inform your doctor regarding any medications, vitamins or supplements you are taking.
- You should refrain from medications or supplements such as blood thinners, aspirin or anti-inflammatory medicines for 1 to 2 weeks prior to surgery.
- You should refrain from alcohol or tobacco at least 24 hours prior to surgery.
- You should not consume any solids or liquids at least 8 hours prior to surgery.
- Arrange for someone to drive you home, as you will not be able to drive yourself after surgery.
- A written consent will be obtained from you after the surgical procedure has been explained in detail.
Procedures Involved with Minimally Invasive Glaucoma Surgery
MIGS is a collection of several operations and involves the following:
- Milder types of laser photocoagulation: Previous laser procedures such as cyclophotocoagulation exclusively reserved for treating advanced glaucoma cases that could not be controlled by trabeculectomy or tube shunts. The procedures were devised to decrease the fluid-forming ability of the eye by specifically targeting the sensitive ciliary body tissue that manufactures the fluid. However, these procedures ended up causing severe eye inflammation that resulted in decreased vision. To address this shortcoming, two recent laser procedures, micropulse cyclophotocoagulation and endocyclophotocoagulation, have proven effective even before far advancement of the glaucoma.
- Totally internal or suprachoroidal shunts: This procedure involves utilizing miniature tubes with very small internal openings to connect the front of the eye to the suprachoroidal space between the retina and the wall of the eye to increase the drainage of fluid. This procedure has minimal complications and is effective in moderate to severe glaucoma cases.
- Trabecular bypass operations: These procedures are mostly employed to treat early to moderate stages of glaucoma. The trabecular meshwork in the eye is mostly responsible for restriction of fluid drainage. Trabecular bypass operations utilize a special contact lens on the eye to place a miniature device through a tiny incision into the trabecular meshwork under a microscope. The trabecular meshwork can either be bypassed or destroyed using iStent or Trabectome devices during these operations.
- Miniaturized versions of trabeculectomy: Microtrabeculectomies involve utilizing microscopic-sized tubes that can be placed into the eye for drainage of fluid from within the eye to beneath the external membrane of the eye (conjunctiva). The two new devices that make microtrabeculectomies safer areXen Gel Stent and PRESERFLO, which have shown remarkable pressure-lowering properties with improved safety over traditional trabeculectomy surgery.
Postoperative Care and Recovery
In general, postoperative care and recovery after minimally invasive glaucoma surgery involve the following steps:
- Arrange for someone to drive you home.
- You should wear a protective eye shield for at least a week at night or while napping to protect the eye from rubbing in your sleep.
- You may experience sensitivity to light, blurred vision, or tearing.
- Keep both eyes closed and rest as much as possible during recovery.
- Limit reading and watching TV for the first few days.
- Do not swim or use a hot tub, spa, or whirlpool for at least 2 weeks to reduce the risk of eye irritation and infection.
- Do not apply eye makeup, cologne, lotions, or aftershave for one week.
- Avoid strenuous activities and heavy lifting for a week so that there is no stress on the eye as it heals.
- You may notice some eye pain or discomfort for the first few days for which your doctor will prescribe medications as needed.
- Steroid and antibiotic drops as well as artificial tears are prescribed to minimize the risk of infection, dry eye, and inflammation.
- Wear sunglasses while outdoors to prevent discomfort from sun exposure and dust in the air.
- You may need to take off work for at least a week or two to facilitate recovery.
- A periodic follow-up appointment will be scheduled to monitor your progress.
Advantages of Minimally Invasive Glaucoma Surgery
Some of the advantages of minimally invasive glaucoma surgery over standard glaucoma surgeries include:
- Extremely safe
- Least disruption/trauma to normal physiology and anatomy
- Reliable intraocular pressure lowering
- Micro-incisional approach
- Quick postoperative recovery
- Minimum follow-ups
Risks and Complications of Minimally Invasive Glaucoma Surgery
Minimally invasive glaucoma surgery is a relatively safe procedure; however, as with any eye surgery, there are potential risks and complications, such as:
- Uveitis (inflammation of the central layer of the eye)
- Iritis (inflammation of the iris)
- Tearing of the inserted device
- Hyphema (accumulation of blood in the eye)