Diagnosis

Regular eye tests at your high street optometrist should mean that diabetic retinopathy will be diagnosed early in the disease. If you are coming in to Moorfields to have the diagnosis confirmed, you will first have another eye test using the charts, and then a full eye examination.

Can I drive to my appointment?

Eye drops will be put in your eyes to make the pupils bigger, as your ophthalmologist must examine the back of the eye through the dilated pupil to make a proper diagnosis. This causes temporary blurring of vision, preventing you from reading and there may be difficulty driving. Because of this, avoid driving yourself to hospital or the local railway station whenever you come to have your retina examined because your pupils will always need to be dilated.

What happens during a typical visit?

A nurse or doctor will check your vision, then drops are instilled into both eyes to dilate the pupil in order that the retina may be examined. After these have had time to work (about half an hour) your eyes will be examined.

You may need to have photographs taken of the back of your eye. These enable the doctor to see and keep an accurate record of what is going on at the back of the eye. They are kept in your records and can be used for later comparisons. You may also need to be tested with a Fluorescein angiogram.

Fluorescein angiography

This is a test used for a few patients:

• to establish the diagnosis and enable the doctor to see why patients may have lost vision,
• to establish if your retinopathy is treatable, and advise you of the prognosis,
• to allow the doctor to see the exact area to direct laser treatment, and
• to allow follow up comparisons.

If you are having this test, your pupils will be dilated (as above). A small injection of yellow dye will then be injected into a vein in your arm. This dye circulates throughout the body and to the retinal blood vessels so that the network of capillaries (small blood vessels) can be easily seen. A series of flash photos will be taken while you are sitting at the slit lamp to show the passage of dye through the vessels in the retina. The doctor will be looking to see whether the dye leaks out of the blood vessels. Dye will not leak out of normal capillaries, and if it is leaking, it means the vessels are diseased or new vessels have developed.

The results and appropriate treatment will be discussed with you, usually on the same visit.

Are there any side effects of Fluorescein angiography?

During angiography some 5% of patients will develop nausea and occasionally sickness that soon passes. Allergic reactions rarely occur. The dye has the effect of yellowing the skin for 3-6 hours and urine for 24 hours. You should avoid prolonged exposure to bright sunlight during this period. Although the fluorescein does not upset your diabetic control, it makes the assessment of your glucose level less reliable, by discolouring the testing strips. You should continue to monitor your diabetes during this period.