What does it involve?
Laser photocoagulation has been a classic treatment in ophthalmology for more than half a century.
It involves the emission of a beam of light concentrated on a single point (laser) of high energy that has an overheating effect on the retina tissue by generating a selective burn.
The treatment has two essential objectives: ablation or destruction of the tissue where the impacts of photocoagulation were felt and the formation of scars on the retina in order to produce adhesion between the layers of the retina and the pigment epithelium of retina.
There are currently multiple laser emission systems in the same application, meaning that the treatment time is reduced and any potential discomfort is minimised.
Furthermore, in the context of retina lesion treatment, a non-thermal laser is applied in photodynamic therapy to activate the active ingredient named Verteporfin.
When is it indicated?
Laser photocoagulation has multiple indications depending on the pathology to be treated.
In the case of diabetic retinopathy, the main indication is to destroy a large part of the retina that lacks oxygen (ischaemic) in order to avoid the growth of new vessels (neovessels) and to prevent haemorrhages in the vitreous gel which would require surgery (vitrectomy).
Laser treatment in the context of macular oedema is kept to very specific cases, as currently the treatment of choice is intravitreal injections.
Another of the main indications of laser photocoagulation is treatment for retinal tears. Our objective is to generate scars that seal the edges of the retinal ruptures to prevent the liquid in the vitreal cavity from filtering down and detaching the retina.
The increase in temperature is also useful in stimulating the formation of thromboses. This is particularly helpful in treating large aneurysms called macroaneurysms.
The destructive effect of the laser is especially useful for treating tumoral lesions that we might find on the retina. However, it is true that there are other less aggressive treatments with good anatomical outcomes.
Another indication of laser is treatment for premature retinopathy where the aim is the ablation of retina tissue without blood supply which could be responsible for the growth of neovessels causing, in advanced cases, the formation of retina detachments that are difficult to manage with surgery.
How is it performed?
Laser photocoagulation is an outpatients treatment that is performed with topical anaesthetic (drops). A contact lens is applied through which the treatment is carried out.
The duration will depend on the area to be treated, but it usually lasts a few minutes. It is a painless procedure and the patient remains seated for the whole duration of the treatment. Once finished, the patient will notice a certain degree of glare which becomes less intense after a few hours.
The laser can also be applied in the theatre, provided that it meets the objectives set out above. The anaesthetic would then be locoregional.
Laser sessions can be repeated according to symptoms presented by the patient.
Complications
A corneal contact lens has to be put in position which may make small erosions. These lesions heal soon after topical treatment has been applied without leaving any kind of sequelae.
The formation of haemorrhages is less frequent after treatment, especially if our objective is to obliterate macroaneurysms.
Excessive scarring in the macula area called the epiretinal membrane has also been described as a side effect to laser photocoagulation treatment.