Photodynamic therapy is applied on the principle of administering a light-sensitive substance called Verteporfin into the body via the arm, and then activating this substance with a low-energy, long-wavelength laser light. We have been successfully performing this treatment at our Foundation’s Bayrampaşa Eye Hospital since 2000, when it was first applied worldwide.
Aim
The aim is to perform the treatment by occluding only the vessels in the targeted area without damaging surrounding tissues — without creating a burning effect or destroying a wide area of tissue — and to preserve tissue integrity as far as possible.
Which conditions is it used for?
It was first successfully applied in patients with the wet types of Age-Related Macular Degeneration (AMD) — known in everyday language as “yellow-spot disease”. In subsequent years, treatment methods in which substances called anti-VEGF are injected into the eye came to the fore, and photodynamic therapy in this patient group came to be applied only in cases of polypoidal choroidal vasculopathy.
Today, in addition to macular degeneration, we use it in chronic central serous chorioretinopathy (CSCR), certain vascular dilatations in the eye called haemangiomas, and ocular tumours.
Central serous chorioretinopathy is mostly seen in the 30–50 age group. Stress is the principal cause; the use of certain medications and certain diseases are among the other known causes. In the macular regions of the retina, fluid leakage develops and the patient experiences reduced vision or distorted, broken vision. The complaints may resolve on their own within a few months. If the clinical findings do not improve or progress further, photodynamic therapy may be applied.
Treatment;
Before the procedure, eye angiography and tomography are performed to identify the lesion or area to be treated. Verteporfin is administered intravenously over about 10 minutes, and about 5 minutes are allowed for the drug to spread through the body. Then, depending on the case, the laser is applied to the targeted area for between one and one and a half minutes. The laser light activates the drug, initiating clotting in the vessels and providing the desired therapeutic effect. After the treatment, however, the patient must be protected from strong light, including sunlight, for about two days. Because the drug spreads throughout the body, in areas exposed to light the drug can become activated, occluding the vessels and causing necrosis. For this reason, patients and their relatives are carefully warned, particularly on this point.
The effect of photodynamic therapy begins to appear after approximately two weeks. Depending on the case and the need, the treatment may be repeated a few months later.
Prepared by the Editorial Board of the Eye Foundation Hospitals.
