Panretinal Photocoagulation Laser (PRP)

Patient Experience

  • Reference Number: HEY-734/2013
  • Departments: Ophthalmology Department
  • Last Updated: 31 May 2023


This leaflet has been produced to give you general information about your treatment.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and your doctor, but may act as a starting point for discussion.   If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team caring for you.

What is Panretinal Photocoagulation Laser?

Panretinal Photocoagulation (PRP) is a type of laser treatment for the eye.  It is used in people who have developed new abnormal blood vessels at the back of the eye in the retina or in the drainage system within the eyeball.

Why do I need Panretinal Photocoagulation Laser?

The PRP laser treatment prevents abnormal new vessels on the retina and in the drainage system of the eyeball from growing and encourages existing ones to shrink and scar up. This makes them less likely to bleed into the jelly in the eye ball (vitreous haemorrhage) or to cause a painful type of high pressure within the eye (neovascular glaucoma).

The PRP laser treatment does not improve vision. The aim is to prevent severe visual loss.

Without this treatment there would be a risk of either losing sight in the eye due to a bleed into the jelly of the eye or of the development of a retinal detachment for patients with new blood vessels which have grown in the retina due to either diabetic related problems (proliferative diabetic retinopathy) or a blocked branch vein (branch retinal vein occlusion).

In patients who have developed new blood vessels in the coloured part of the eye (iris) due to a blocked vein in the eye (central retinal vein occlusion) there would be a risk of developing a painful eye due to blockage of the fluid inside the eyeball caused by growth of new blood vessels in the eyeball drainage system.

In this case the aim of the treatment is not to prevent loss of vision as there will already be very poor vision that cannot be improved due to the underlying disease. The aim is to prevent the eye becoming painful through a build-up in fluid in the eye raising the pressure in the eyeball.

Can there be any complications or risks?

There is good scientific evidence that laser treatment will significantly reduce the risk of your vision deteriorating.  It also reduces the risk of the eye developing painful high pressure.

The laser treatment can reduce the peripheral (edge) field of vision. You may not notice the effect of this. However it might mean you will not meet the visual legal requirement for holding a driving licence, particularly if both eyes need treatment. You need to inform the DVLA if you are having this laser treatment in both eyes. Ask the doctor about this if you are a driver.

Your night vision and contrast sensitivity may be reduced and your colour vision altered in the eye having the treatment.

Rarely your vision may be worse after the treatment. This can be caused by a build up of fluid at the back of the eye (macular oedema), bleeding within the eye (vitreous haemorrhage) if the abnormal blood vessels don’t regress. Rarely, unintended burn to the centre of the retina may cause permanent deterioration of vision.

Rarely, the pupil may remain dilated for longer duration after PRP laser treatment (sometimes, dilated permanently) which may cause glare, light sensitivity and near vision difficulties.

How do I prepare for the Panretinal Photocoagulation Laser?

Please read the information leaflet. Share the information it contains with your partner and family (if you wish) so that they can be of help and support. There may be information they need to know, especially if they are taking care of you following this examination.

  • It is essential that you do not drive to and from your appointment as you will be having dilating drops in the eye under-going treatment. These drops will blur your vision for up to 6 hours after the treatment.
  • You can expect to be at the hospital for a minimum of 2 to 4 hours.
  • Diabetic patients are advised to ensure they have enough food and medication that they may need during the visit.
  • Refreshments are available at the Fountains Cafe in the Atrium of the Eye Hospital. When this is closed limited snacks are available in a vending machine in the café or at the Women and Children’s Hospital.
  • Please take all your normal medications prior to this treatment.
  • You may eat and drink normally unless you have been advised not to do so.

What will happen?

This treatment is usually carried out in the Eye Hospital Outpatient department.  Please report to the Eye Hospital Reception desk when you arrive. In some cases the treatment is carried out in the Operating Theatre.

You will be directed to the Eye Clinic waiting area or Eye Hospital Day Case Unit.

  • A nurse will check your vision and instill some eye drops to dilate the pupil.  These drops will blur your vision for 4-6 hours. These drops are  to allow the doctor to see the back of your eye when carrying out the laser treatment.
  • You will be asked to sign a consent form for the treatment and specific risks to your eye condition will have previously been discussed with you at a separate visit.
  • PRP laser treatment involves applying many laser burns to the edge of the retina (lining at the back of the eyeball).  It is often done over a number of different sessions.
  • You will be shown into the room where the laser treatment is to be carried out. 
  • A local anaesthetic drop or injection may be used before the laser treatment is given.
  • The laser is applied with either a light worn on the doctor’s head or by a microscope with a chin rest similar to the one used in clinic to examine your eyes and usually a special contact lens.

 The treatment usually takes 15-30 minutes depending on how much treatment is required in your particular circumstance.

What happens afterwards?

  • Following the treatment you can go home.
  • This laser treatment is not a painless procedure. You may notice discomfort or a dull ache in the eye during or after the treatment. This can be helped by taking pain relief medication as you would for a headache (e.g. paracetamol).
  • Your vision will be “dazzled” or may seem darker after the treatment. This effect can last for 24-48 hours.
  • You should avoid driving for 24 hours after the treatment.
  • A follow up appointment will be arranged for either a further session of PRP laser (if required as part of a course of treatment) or for a follow-up check in a few weeks to check that the eye is responding to the treatment. This varies depending on the reason you are having the laser treatment for.
  • It may be necessary for further treatment to be carried out.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Ophthalmology Department on tel no: (01482) 608788.

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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