Pan-retinal photocoagulation or PRP is a technique used by experts like Eye Specialist in Karachi to treat conditions of the retina that pose the risk of long-term retinal damage and even blindness. PRP is a type of laser therapy to preserve vision and prevent exacerbation of retinal diseases. Read on to know more about PRP and the conditions it treats:

What is pan-retinal photocoagulation?

Laser photocoagulation uses heat on the retina to stop the growth of newly forming leaky blood vessels responsible for retinopathies in the eye. The laser helps in regression of the blood vessels growing in the eye that are leaky, and destroys them before excessive fluid leaks onto the retina. If these abnormal blood vessels are allowed to grow unchecked, they can cause irreversible vision loss and even blindness.

Pan-retinal photocoagulation is not applied to the whole retina but only to the peripheries of the retina, with the central retina remaining intact. PRP has been used for years to treat diabetic retinopathy and has a good prognosis following the procedure.

This procedure is performed by a retina specialist.

Who needs pan-retinal photocoagulation?

Pan-retinal photocoagulation is done in patients with long-standing uncontrolled diabetes and ischemic diseases of the retina. As a consequence of disease, new blood vessels grow on the retina and cause vision problems. When these new and fragile blood vessels leak, they cause edema in the retina and development of hemorrhages with the patient complaining of floaters and spots in vision. If blood leaks from these vessels, it can also collect in the vitreous leading to vitreous hemorrhage.

Without treatment, the patient is at risk of:

• Retinal detachment: if the new blood vessels pull on the retina, the retina can detach from the back of the eye. This condition is called retinal detachment. 
• Blindness: patients can lose complete vision due to bleeding of these weak vessels.
• Proliferative diabetic retinopathy: the disease can advance further into the proliferative stage called proliferative diabetic retinopathy.
• Central retinal vein occlusion (CRVO): there is risk of developing blockage of the venous flow of the eye which is a painful condition.
• Neovascular glaucoma: leakage of fluid from the weak blood vessels can also raise the intraocular pressure (IOP) and cause neovascular glaucoma.

How is pan-retinal photocoagulation performed?

• Pan-retinal photocoagulation is performed by a qualified retinal specialist in hospital setting. The procedure can be performed in the outpatient department with no hospital stay. The overall time in the hospital for this procedure is around 2 to 4 hours.
• The patient is directed to come accompanied by someone and not drive themselves as they will have blurry vision following the procedure, for a period of at least 6 hours.
• No other medication needs to be stopped before the procedure and the patient can eat and drink as they please, unless directed by the healthcare provider.
• Typically, the procedure is performed at a slit lamp microscope after the pupil of the patient is dilated pharmacologically and local anesthetic drops are applied. Alternatively, the healthcare provider may inject a local anesthetic to minimize the discomfort during the procedure. This injection is injected just under the eyelid and can cause slight ‘black eye’.
• Thereafter, a beam of special laser is thrown on the peripheral retina over multiple sessions. As the burn is applied on the retina, the patient feels a slight pinching sensation. The whole procedure lasts for 15 to 20 minutes.
• The treated eye is patched after the procedure. This patch can be taken off the next day.
• Over-the-counter pain medication is enough to manage the discomfort associated with the procedure.

What to expect after the procedure?

Pan-retinal photocoagulation is not done to improve vision. Rather, this is just a treatment option offered by experts like Dr. Huma Kayani to reduce the risk associated with diseases like diabetic retinopathy and to save the eye from subsequent visual loss. Following the procedure, expect mild pain and blurred vision that typically lasts for a week.