Pan Retinal Photocoagulation: Indications, Session Parameters and Equipment

What pan retinal photocoagulation does

In ischaemic retinal disease, oxygen-starved retina releases vascular growth factors that trigger fragile new vessels. These can bleed into the vitreous or pull on the retina. PRP deliberately destroys areas of peripheral retina, which lowers oxygen demand and reduces the stimulus for neovascularisation.

The trade-off is the loss of some peripheral and night vision, which is why the extent of treatment, spot spacing and staging are discussed by the retina specialist and the patient. PRP does not restore vision; it aims to protect the central retina from complications.

Indications: PDR, CRVO and others

The classic indication is proliferative diabetic retinopathy (PDR). PRP is also used for neovascularisation after central retinal vein occlusion (CRVO), ischaemic branch occlusions, some sickle-cell retinopathies and selected neovascular glaucoma cases, usually with other measures. Indications and timing are decisions of the treating ophthalmologist.

Fundus imaging and fluorescein angiography help to map ischaemia before treatment and to document response afterwards, so retina clinics normally pair a laser with imaging.

Session parameters for PRP laser

Published practice usually divides PRP into several sessions, with a total of roughly one to two thousand burns placed in a scatter pattern, avoiding the macula and major vessels. Spot sizes are often set at about 200–500 µm at the retina, with exposure in the tens to hundreds of milliseconds and power titrated to a moderate grey-white burn. Shorter pulses and pattern scanners can reduce discomfort.

The CLASSIC 514 is a slit-lamp-coupled 514 nm photocoagulator with up to 1.2 W, spot size selectable from 50 to 600 µm, pulse length from 15 ms to 2 s, repetition rate of 1–5 Hz and single-pulse, gated and micropulse modes. The manufacturer notes that, according to user feedback, the 514 nm wavelength is associated with lower pain perception than KTP lasers. These figures are device data; the clinical protocol remains the surgeon's.

Common mistakes include treating with energy that is too high for the lens used, placing burns too close together in the first session, and failing to record the number of burns and settings. A simple template in the patient file, completed after every session, avoids these errors and supports follow-up decisions.

Laser and lens set-up for retina clinics

PRP is delivered through the slit lamp with a wide-field contact lens such as a panfundoscopic type, or with an indirect ophthalmoscope for patients who cannot sit at a slit lamp. Lens magnification changes the effective spot size on the retina, so the surgeon corrects the setting for the lens in use.

For clinics that need more than one laser, the VARIO combines two A.R.C. lasers (for example CLASSIC 514 with Q-Las or CITO 532) on one table with two slit lamps. For broader context read retinal photocoagulation lasers and micropulse laser in ophthalmology.

Practical checks before purchase include the ergonomics of the slit lamp for long sessions, the readability of the display from the side, filter quality for the physician, the availability of a pattern scanner or micropulse option, and how the laser is protected against accidental firing. Ask how the unit is calibrated, who performs the annual power check and how quickly a service engineer can attend in the UAE. Staff should also be trained on lens handling and cleaning.

PRP and anti-VEGF: complementary tools

Anti-VEGF injections can regress neovascularisation and treat macular oedema, and clinical trials have compared them with PRP in PDR. They require repeated visits and long-term adherence, whereas PRP is a one-time course that has a lasting effect, which makes it valuable where follow-up is uncertain. Many retina services use both, and the choice is individual.

To plan a laser set-up for a retina clinic, contact Beckfinity for specifications and a proposal.