Trabeculectomy: is it the commonest way to treat glaucoma?
Written in association with:
Ophthalmologist
Published: 28/06/2019
Edited by: Laura Burgess
There are a number of ways to treat glaucoma including eye drops, laser and surgical approaches. All of these approaches aim to reduce eye pressure in order to minimise the risk of glaucoma progression.
Surgery is required if eye drops and laser treatment are not effective at lowering the eye pressure or glaucoma continues to progress. Surgical options include glaucoma filtration surgery (trabeculectomy), glaucoma drainage device surgery, non-penetrating glaucoma surgery and minimally invasive glaucoma surgery (MIGS).
We’ve asked one of our top eye specialists Dr Richard Lee to explain everything you need to know about the trabeculectomy procedure, including what happens, whether you’re left with any scarring, the success rate and if it’s the most common surgical procedure used for treating glaucoma.
Is trabeculectomy the commonest way to treat glaucoma?
Trabeculectomy is a procedure that has been in use for just over 50 years and therefore is one of the most common procedures for glaucoma, however, in some parts of the world, there is an increase in drainage device surgery being performed compared to trabeculectomy.
MIGS devices are also relatively new and therefore not as commonly performed as trabeculectomy at present. Given that they are less invasive and with less risk of complications than trabeculectomy, we may find that these become more commonly performed than trabeculectomy in the future.
It is important to note however that MIGS devices are generally used for early to moderate glaucoma and that there still continues to be a role for trabeculectomy surgery in the management of glaucoma.
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What happens during the procedure?
The aim of trabeculectomy surgery is to allow the fluid inside the front part of the eye (the anterior chamber) to drain over the white of the eye (the sclera) and underneath the ‘skin’ of the eye (the conjunctiva). This can be performed with local or general anaesthesia.
During the procedure, the conjunctival layer is moved out of the way to reach the sclera. A drainage pathway is created underneath the conjunctival layer and an anti-scarring agent is applied to this space to reduce the risk of the drainage pathway closing again. A ‘trap door’ (the flap) is made in the sclera to allow fluid to drain from inside the eye to underneath the flap and subsequently to the space between the conjunctiva and sclera. The flap is held down by sutures that may or may not need to be removed in the clinic following surgery based on the eye pressure after surgery. The conjunctival layer is then repositioned with sutures, allowing a pocket of fluid to drain underneath it (the bleb).
Will there be any scarring?
An anti-scarring agent (mitomycin C) is applied during surgery to reduce the risk of scarring and to allow the fluid to drain underneath the conjunctiva. Following surgery, anti-inflammatory steroid drops are used over several months and if need be can be injected underneath the conjunctiva in the clinic following surgery to help reduce scarring. Despite these measures, some eyes are more prone to scarring than others and may require further medical or surgical intervention.
What are the risks and complications of the procedure?
As with any operation, there are risks of discomfort, bleeding, inflammation and infection. Following surgery, you will be monitored closely in the clinic and asked to use both anti-inflammatory and antibiotic drops, often for several months.
Additional risks include the eye pressure being too high or too low and additional procedures in clinic such as removal or manipulation of the flap sutures may be necessary.
There is a risk of reduced vision or cataract formation. In the worst case scenario, there may be a complete loss of vision although thankfully this risk is low.
It is also important to note that as the eye heals, over time the eye pressure may increase and you may require further medical or surgical treatment.
What’s the success rate?
A number of modifications to the surgical approach have been developed to improve the success rate of surgery. As such, the success rate can be as high as 80-90% at one year with or without drops to control the eye pressure.