Overview

This information is for anybody who has diabetic eye screening using phenylephrine 2.5% eye drops. Diabetic eye screening is a test to check for eye problems caused by diabetes.

Phenylephrine is a medicine that we use in some cases to widen (dilate) the pupils (black centres) of the eyes. This allows us to examine the back of your eyes in detail. We give you phenylephrine as eye drops.

The medicine that we routinely use for diabetic eye screening is called tropicamide. We use phenylephrine eye drops as well if you have:

• small pupils
• dark irises (the coloured parts of the eyes around the pupils)
• a poor response to the tropicamide eye drops and they do make your pupils wide enough 

Tropicamide and phenylephrine work together to open your pupils more widely.

The effects of the eye drops can last for up to 6 hours. It is important to:

• know the possible side effects until your sight returns to normal
• recognise when you may need to get medical advice

If you have any more questions, please speak to a health professional looking after you.

Diabetic eye screening

If you have diabetes and are aged 12 or over, you will get a letter asking you to come for a diabetic eye check at various intervals. The time intervals depend on your previous screening results.

There is a national diabetic eye screening programme. If you live in south east London, the south east London diabetic eye screening programme offers this service.

Diabetic eye screening is a way to check for any eye problems caused by diabetes. These problems are called diabetic retinopathy and can lead to sight loss if not found early. 

We use eye drops to make your pupils bigger. Then, we take good quality, digital photos of the back of your eyes. This helps us to find any problems before they affect your sight.

Side effects of the eye drops

The eye drops have some short-term side effects. These can include:

• blurry sight
• being sensitive to bright light
• temporary stinging and a dry mouth after using the eye drops

The effects of the eye drops usually last 2 to 4 hours, but can continue for up to 6 hours. There are things that you can do to stay safe and comfortable during this time.

Rare complications of the eye drops

Very rarely, the eye drops can cause a sudden, dramatic rise in pressure within your eye. This is called acute glaucoma and needs to be treated quickly in an eye unit.

If you are concerned about any other symptoms after diabetic eye screening, please contact a GP. There is information on other possible side effects in the manufacturer's leaflet for the eye drops. Please ask our staff if you would like a copy.

You can find emergency departments with a specialist eye casualty (offering an accident and emergency eye service) at these hospitals:

• St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH (before coming to the hospital, you need to book an urgent appointment with our rapid access eye service by calling 020 7188 4336, Monday to Friday, 8:30am to 4pm)
• King's College Hospital, Denmark Hill, London SE5 9RS
• Queen Mary's Hospital, Frognal Avenue, Sidcup, Kent DA14 6LT (you first need to go to the main A&E, which can then send you to the eye unit)
• Moorfields Eye Hospital, 162 City Road, London EC1V 2PD (phone: 020 7566 2345 or 020 7253 3411 out of hours)