Glaucoma surgery is necessary for my patients when drops or simple laser treatments such
as SLT laser are unable to control the pressure at a sufficiently low level to stop the glaucoma
from getting worse. We always start patients with glaucoma with either simple laser treatments
such as SLT or drops treatment before recommending surgery. Overall, I think about 20% of my
patient with glaucoma will require glaucoma surgery in their lifetime. We have to remember
that glaucoma damage is a permanent damage to the eye. Therefore, we must recommend glaucoma
surgery at a timely manner. For example, patients who are getting worse very rapidly will may
well need glaucoma surgery urgently, while patient who require glaucoma surgery who--
glaucoma surgery is progressing at a much slower rate may not need urgent surgical intervention.
So, it is important to establish whether, A: patients have tried all sorts of simple
drops treatment and simple laser treatment before recommending surgery and the next one
is to establish how quickly one needs to perform the glaucoma surgery depending on the speed
of the progression of their glaucoma.
There are over ten types of glaucoma surgery one can perform for our patients, but perhaps
it's easier to categorise them into three groups. The first one being laser treatment
ranging from the simple SLT treatment which can be performed in our patienst to more invasive
lasers such as micro pulse laser or EZP laser which need to be performed in theatre. The
second group is a relatively new category which is called the mixed devices or minimally invasive
glaucoma surgery. This type of surgery tends to be much quicker to perform and also carries
much less intensive post-operative management but they tend not to achieve the very low
pressure post-operatively; and the finally the third one will be the more traditional
glaucoma surgeries such as trabeculectomy, implant surgery which could include XEN implant,
barbell implant or armoured valve implant. Obviously, all the glaucoma surgery carries
advantages or certain disadvantages. It is important that we tailor different types of
surgery for patients with different type of glaucoma and varying severity of their glaucoma.
For example, patients with advanced glaucoma may need very, very low pressure postoperatively,
therefore mixed devices may not be suitable for those groups of patients. So, in summary
I think it's important to choose the right type of surgery for our patients, because not
all surgery is suitable for all.
The most common filtering glaucoma surgery in my practice still remains trabeculectomy.
This is a surgery that has been around since the 1960s that remains one of the best surgical
techniques that we have. It is commonly used in conjunction with anti-scarring agents such
as mitomycin-C to improve the long-term success rate. Now it is a fairly invasive surgery.
It takes between 30 to 45 minutes to perform and generally will require a local anaesthetic
or general anaesthetic in theatre. It is very successful but it is also quite invasive,
therefore, it carries higher risk of complication. But because it really does achieve very low
pressure postoperatively, it is usually the recommended surgery of choice for patient
with advanced glaucoma. Conversely for what we call non-invasive glaucoma surgery, the
most common one that I perform is probably either micro pulse laser or ECP laser. Micro
pulse laser tends to be a standalone procedure under local anaesthetic, while ECP laser tends
to be combined with cataract surgery. Both are equally effective. Obviously, a patient
with early or moderate glaucoma will be a sort of my target patient for this type of
procedure.
Glaucoma surgeries are generally performed in operating theatre apart from SLT laser
which can be performed in our patient setting. The patient needs to be lying down on operating
theatre and surgeons tend to use an operating microscope to perform the surgery. Surgery
duration takes between five minutes for certain types of laser to an hour for more involve
surgery such as glaucoma tube surgery. Trabeculectomy takes around 30 to 45 minutes. So the choice
of anaesthetic will depend on the types of surgery involved. It can be local anaesthetic
to sedation or even general anaesthetic. I think the choice of anaesthesia would depends
on patient preference and the surgeon's preference to a certain extent. In general, if a surgery
requires more than 45 minutes, they probably safer and more comfortable for our patient
to be done under general anaesthetic. One of the final thing is post-operative care.
I think aftercare is really pretty much a part of glaucoma surgery. Laser or mixed devices
tend to be much less involved. So one to two visits post-operatively would be sufficient
while the tube surgery or trabeculectomy will may well require five to six post-operative
visit in the first three months.
The success rate for glaucoma surgery varies enormously. I think you could go from one
extreme of a mixed surgery which could or may only have 40 percent success rate to trabeculectomy
which could have 80 to 90 percent success rate. However, one has to take into account
that the risk of surgery is greater in trabeculectomy compared to mixed surgery which is generally
very low risk procedure and also much quicker to perform. So, it's important to take both
into account. But perhaps more importantly, when you look at successful glaucoma surgery,
it all depends on what our patient needs. For example, a newer glaucoma surgery could
have a success rate of 80%, but it may only have 20% chance of achieving very low pressure
post-operatively. So, for example, patient of advanced glaucoma mainly pressure of 12.
Now if you look into this data of success rate, you might find that to achieve that
level of pressure, the success rate for this new type of glaucoma could only been 20%.
Therefore, you would be-- for me, it would be considered inappropriate. So it is important
to understand that reported success rate varies enormously and also the different level of
pressure they achieve postoperatively vary enormously. It is important to find the right
type of glaucoma surgery depending on the severity of patient's glaucoma and also expectations
of how patient can or frequently attend post-operative visit.
The recovery from surgery very much depends on the types of surgery performed. For example,
eye stent or hydris, which is considered the mixed devices, the recovery can be very
quick. In fact, patient could go back to completely normal activity within one to two days. Likewise,
for lasers such as micro pulse or ECP laser, the patient can go back to normal activity within
a couple of days with no restrictions on exercises or driving even. However, more invasive surgery
such as trabeculectomy or tube surgery, those are surgeries that require much longer recovery
time. I would say minimum of two weeks off work, certainly no strenuous exercises for
two to three weeks. Again, depends on how they're doing post-operatively, but I always
urge my patients to prepare for at least four to six weeks of slightly blurry visions after
trabeculectomy or tube surgery. It is important that we understand that those surgeries such
as tubes or trabeculectomy are more involved, but also, they can achieve much better long-term
pressure control for patient with advanced glaucoma. They are slightly more involved
early on but the benefit long-term is very pronounced.