Patient information: Retinopthy of Prematurity
What is the retina? 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 retinopathy of prematurity?
Retinopathy
of prematurity (ROP) occurs in prematurely born infants
whose retina fails to develop normally. An imbalance in the
oxygen supply to the retina means that new blood vessels grow inside
the eye. These fragile new retinal vessels may bleed, or leak
fluid that causes retinal scarring. In severe cases, the scarring
can lead to retinal detachment, where the retina comes away from the
back of the eye. If this involves the macula, then the vision can
be severely affected. For this reason, infants born at less that
32 weeks old, or less than 1500 grams, are screened for ROP by an
ophthalmologist (eye doctor). This screening occurs while the infant is
in the hospital, shortly after birth. Most infants who are
screened do not develop ROP, but those that do are kept under
close review.
How is retinopathy of prematurity treated? A
minority of those with ROP develop progressive changes that
can threaten the vision, and in this setting the ophthalmologist may
recommend treatment. This
is usually undertaken with a laser, or sometimes a freezing probe
(cryoprobe). Treatment is designed to reduce the oxygen needed
by the eye, and thereby reduce the stimulus for new vessel growth
and scarring of the retina. In most cases the treatment is
effective at
stopping new vessel growth, and virtually all ophthalmologists feel
that this type of treatment is worthwhile for those who need it.
In a small number of infants,
despite the best possible treatment, the scarring process continues,
and they develop more advanced disease. Those with retinal
detachment can be treated with surgery, but the outcome of surgery is
not certain. Some children may benefit, but not all, and surgery
involves risks such as loss of vision, further surgery,
worsening of the retinal detachment, glaucoma, and corneal problems.
For this reason, surgery for ROP is contentious. Some surgeons feel that the risks of surgery outweigh the benefits. Other surgeons
feel that, since there is no viable alternative, parents should have
the option of surgery, as long as they understand the risks and that vision will not be normal.
Parents faced with the difficult decision of whether or not to
allow their child to undergo surgery for advanced ROP should not
be afraid to ask questions; they should be confident that they
understand the issues before making up their mind. As a
retinal surgeon who feels that some children may benefit from surgery,
I am happy to discuss these issues with parents. I can also
provide contact details for those who wish to seek a second opinion
from a surgeon who does not feel surgery is worthwhile, so parents can
hear both sides of the argument.