Patient information: Macular hole
What is the macula? The
retina lines the inside of the back of the eye. It
functions a bit like the film in the back of a camera, in that it
absorbs light to form an image of the outside world.
The most important part of the retina is the macula - this is the part
of the retina that the light is focussed on. It gives
the central vision that is important for fine visual tasks such as
reading and driving.
What is a macular hole? As
the name suggests, it is a hole in the macula. It produces blurred
or distorted vision although some patients are more affected than
Laser image (OCT) of a macular hole
Do I need surgery? This
depends on a number of factors. Firstly, the severity or stage of
the hole. Early, less severe holes may not respond to surgery, and
equally, neither may very advanced, longstanding holes. Without
surgery most holes remain much the same and they do not go on to cause
total loss of vision. Occasionally they heal themselves but this is
rare in cases other than very mild macular holes. For most patients the
best chance of visual improvement is with surgery.
What does surgery involve?
The name of the operation used to treat macular hole is vitrectomy, internal limiting membrane
peel, and intraocular gas injection. Dealing with each in
turn: vitrectomy involves a microsurgical procedure to remove the clear
gel (vitreous) that fills the inside of the eyeball. This gel is
99% water and the body will refill the eyeball with water again after
surgery. Internal limiting membrane peel involves removal of the
innermost layer of the macular - this is thought to promote
closure of the macular hole. Last, a gas is injected into the eye, until such time as the body replaces it
with its own water. This gas helps push the hole closed and for
this reason many patients are asked to assume a face down position
after surgery to float the gas bubble into the correct position,
although the benefit of face down posturing is hotly debated amongst
retinal surgeons. The operation can be performed under a local
anaesthetic (awake but with an injection to numb the eye), or general
anaesthetic (asleep). It takes about 45-60 minutes.
What are the potential benefits of surgery? In
about 80-90% of patients the macular hole closes after surgery, but the
effect on vision is variable. About two-thirds to three-quarters
experience a useful improvement in vision but few obtain 100% normal
vision. If the hole fails to close after the first operation it is
usually possible to re-operate.
What are the risks of surgery?
Any eye operation caries some risk. Serious,
sight-threatening complications such as haemorrhage or infection
are thankfully extremely rare and occur in only about 1 in
500 patients. In those that haven't previously had cataract
surgery the macular hole surgery will tend to promote cataract
formation and it is likely that this will need surgical treatment at
some time in the future. Other complications such as
retinal breaks or retinal detachment occur in less than 5% of cases but
they can usually be treated.
Are there any particular precautions after surgery? Yes.
Your nurse will go through the general instructions for someone who has
just had an operation such as keeping the eye clean, use of eyedrops,
and follow-up appointments, however after macular hole surgery there
are two specific restrictions. Firstly you must not go up to high
altitude as the gas in the eye will expand and this puts the eye
pressure up. Hence you cannot fly, or go up high mountains until
the gas absorbs -this can take 1-2 months depending on what type of gas
is used. Secondly, if you need a general anaesthetic you
must inform the anaesthetist that you have gas in the eye to
avoid certain anaesthetic gases.
Any further questions? When
you come for a consultation we will go through the pros and cons of
surgery but if you have any further questions please do not hesitate to
ask me or one of my team. It may be possible to arrange for you
to talk to someone who has had macular hole surgery - just ask. If you drive you should check with us whether it is safe to continue.