A cataract is an opacity in the lens within
the eye. It upsets the focusing mechanism and patients usually complain of blur. It
might be useful if we looked a model eye to start with. Cornea at the front of the eye,
a clear window allowing the light through. The iris which everyone is familiar with I’m
sure. The lens sitting behind the iris, this is where a cataract develops. Light rays normally
focus by the cornea through the pupil on to the lens. Lens then focuses light on to the
retina. If the opacity lies within the lens, it is
not able to focus light. The image is blurred. Patient complains of difficulty with spectacles,
difficulty reading road signs or reading small print, or glare off bright lights.
Modern cataract surgery is so successful that in the majority of cases, it’s really driven
by patient demand. Some patients will want cataract surgery at a very early stage because
they wish to reduce their requirement for spectacles at the same time. Others will of
course prefer to put off surgery and avoid any potential complications and interventions
until they’re really struggling. So it’s a very personal decision when a cataract surgery
is carried out. The usual drivers are of course blurring of vision to the extent where one
is happy to enter hospital and have a surgical procedure.
Modern micro incision cataract surgery is carried out by making incisions on the cornea
allowing access through the pupil to the lens. The incisions are now around 2mm in length
which allows them to be self-sealing so no sutures are required. The eye recovers very
quickly because of the micro incisions. And as a result, vision is usually very good within
a few days. The cataract is removed and then an artificial
lens is inserted into the eye. It’s obviously not to scale. The artificial lens usually
consists of a central optic which takes the place of the natural lens and focuses the
light, together with these legs or haptics which spring against the wall of the eye and
hold the artificial lens in place. The majority of cataract operations are carried out using
phacoemulsification or ultrasound power to break up the lens allowing its removal through
the small incision. There’s a very low risk of retinal detachment
following cataract surgery and for the majority of patients, that shouldn’t be a major concern.
The most serious risk following an operation on your eye is infection and that’s about
one in a thousand. Retinal detachment, if it happens, can usually be treated surgically
and is more frequently found in those patients who are very short-sighted and are at higher
risk of retinal detachment anyway due to their short-sight.
Well, as eye surgeons, we’re very fortunate in that we carry out one of the most commonest
procedures in the world and also one of the safest. The vast majority of patients have
completely uneventful cataract surgery as a day case procedure often under just anaesthetic
drops. There is of course a small risk as there is with any surgical procedure and if
you added all these risks up, there’s probably about a 1% chance that you will be very unhappy
with your outcome following routine cataract surgery.
The vast majority of patients would have reasonable vision certainly the following morning after
their cataract surgery the previous day. The advantage of the very small incisions that
we now use is that one has a very rapid recovery. Most people would not require any pain killers
at all maybe the occasional paracetamol or some mild analgesic. Vision is pretty good
within a few days. I usually tell my patients not to drive for a week. Most of them tell
me they are in fact driving within a week. The rules are that you have to be comfortable
with your eye following surgery and of course able to read the number plate.
Patients will usually be asked to use drops four times a day for four weeks after their
operation. And I would normally see a patient two to three weeks after the initial procedure.
Assuming all is well, they would then go and visit their optician for up to date spectacles
around one month after the initial cataract operation.