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.