Mr Tanner has advised you to have an injection of Triamcinolone steroid
into your eye as recent evidence has suggested that this form of treatment
is very effective in decreasing swelling and oedema at the back of your
eye, particularly the central area of the retina known as the macula.
Over the last few years an increasing number of studies has suggested
that Triamcinolone injections are of benefit in a wide variety of conditions
including vein occlusions, diabetic macular oedema, post operative macular
oedema and also when used in conjunction with photodynamic therapy in
the treatment of age related macular degeneration.
What is Triamcinolone?
Triamcinolone Acetamide
(Kenalog) is a synthetic corticosteroid which can be injected via a
very fine needle through the wall of the eye into the vitreous cavity.
It then sits there as a deposit in the eye allowing the steroid effect
to work on the macula over approximately a four month period.
Although injecting
steroid into the eye is of course associated with some risks, as is
any other surgical procedure, serious problems are rare. The steroid
is injected into the eye as it is felt to have a far greater effect
when placed directly in contact with the retina and avoids many of the
side effects associated with oral steroid use.
How does it work?
Triamcinolone works
by reducing inflammation and stopping fluid leaking out from abnormal
or damaged blood vessels in the retina. As a result of these leaking
vessels the macula often becomes swollen with an associated drop in
vision. The duration of effect seems to be three to four months after
which a repeat injection may be required although in many cases the
leaking process can be switched off by the high dose of steroid used.
This is particularly so with age related macular degeneration, where
the combined use of steroid injection has decreased the numbers of PDT
laser treatments required from six or seven to only two or three.
The procedure itself
The steroid injection
is carried out in the operating theatre to minimise the chance of any
infection occurring during the process. The injection is given under
a local anaesthetic and is not painful in any way. As the steroid is
injected you may well notice some black floaters in the eye, or a cloud
like effect, which is the steroid entering the eye. Vision is normally
clearing by the day following surgery and you can resume normal activities
although many patients notice the steroid as floaters in their eye for
the first few weeks.
What are the risks involved?
The recognised
complications of this procedure include:
- High
pressure in the eye - in up to 40% of patients the pressure in the
eye may rise requiring the use of eyedrops to bring it back down
to normal levels. A pressure rise is usually painless and has not
been associated with any adverse affects. For this reason the pressure
is checked in the eye at one week, one month and three months following
the injection.
- Glaucoma
- in approximately 1% of patients the pressure rise is more substantial
and more prolonged drop use or possibly even surgery is required
to drop the pressure back to within normal limits.
- Cataract
- there is some evidence to suggest that cataract formation is increased
following intravitreal injection of steroid. The incidence increases
with a greater number of injections. Cataract can be dealt with
by routine surgery as required.
- Endophthalmitis
- there is a 0.5% risk of developing serious infection in the eye
following an injection, which can result in visual loss. This is
of course the most serious complication following intravitreal steroid
injections and this is why every precaution is taken to avoid any
infective risk while the procedure is carried out in the sterile
operating theatre.
- Bleeding and retinal detachment are unusual complications which
may occasionally require treatment.
You will be asked to sign a consent form prior to the injection in the
operating theatre stating that:
- You understand
why the procedure is being performed;
- the expected
outcome in your particular situation;
- the potential
complications of the procedure.
If you have any
further questions please do not hesitate to ask me or my team and we
will of course do our best to answer them.
