Visual acuity and retinal examination should be performed
annually on all diabetic patients after 12 years of age, or more
often if advancing changes are observed.
Vision-threateningretinopathy rarely occurs in Type 1 diabetes in the first five
years after diagnosis or before puberty.
However, more thanone-quarter of Type 2 diabetic patients have been found to
have retinopathy at diagnosis, and screening should start
immediately.
Visual acuity should be checked annually, or more often if
significant retinopathy is present or if it has changed unexpectedly. This should be done with patients wearing theirspectacles or through a “pinhole” if they are not.
Retinal examination. Routine fundal examination should be
performed on all diabetic patients, using fundoscopy or retinal
photography or preferably both.
The pupils should be dilated
and the fundus examined in a darkened room. Tropicamide
1% (Mydriacil) eye drops are recommended as they have a
short duration of action of just two to three hours. There is no
reason to avoid pupillary dilatation in patients being treated for
chronic open-angle glaucoma, although those on treatment for
closed-angle glaucoma must not undergo pupillary dilatation.
Once background retinopathy is present the patients should
be examined every six to 12 months or more often if there is
any change of visual acuity, and referred to an ophthalmologist
when indicated (see box). Pregnant patients require more
frequent follow up as retinopathy may progress rapidly during
pregnancy (see page 78).
Screening methods
Conventional examination, using an ophthalmoscope in a
darkened room with the pupil dilated is a minimum
requirement. Observers must be well trained, but even
consultant ophthalmologists do not achieve the required
80% sensitivity.
Retinal photography through dilated pupils.
The preferredmethod now uses digital photography which yields suitable
images which can be electronically stored, making them easily
available for consultation, review, and teaching.
Conventionalcolour photographs also provide good images, whereas the
quality of Polaroid photographs is less than ideal.
It would be ideal to provide both conventional funduscopic
and photographic screening procedures, and there is already
some evidence that the combined screening procedure reduces
the failure rate.
A national screening programme has been
proposed and has already been adopted in Wales
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