Photodynamic therapy (PDT) for the eye

Photodynamic therapy (PDT) is a medical procedure that combines a light sensitive medication with targeted laser light activation. The goal of PDT is to selectively affect abnormal blood vessels or diseased tissues in the eye, while minimizing damage to surrounding healthy tissues. It is considered a treatment option for certain conditions affecting the retina and choroid.

PDT is considered for specific eye conditions, primarily those involving the growth of abnormal blood vessels or fluid leakage from the choroid (the vascular layer beneath the retina) or the retina itself. Examples include certain types of age related macular degeneration (AMD) with polypoidal choroidal vasculopathy (PCV) and chronic central serous chorioretinopathy (CSCR). The decision for PDT suitability is made by an ophthalmologist after a comprehensive examination and accurate diagnosis.

Treatment begins with an intravenous infusion of verteporfin into the arm. Once the medicine has reached the target tissues, a carefully timed, focused laser light activates it in the planned area. The resulting reaction affects selected choroidal vessels and can reduce leakage; the dose and light settings are tailored to the condition. PDT aims to control disease activity and protect vision, but benefit is not guaranteed, and repeat treatment may be needed. The eye treatment is usually not painful, although discomfort or pain can occur during the infusion, and eye tissues can be harmed in some cases.

Before treatment, comprehensive eye examinations will be performed, which may include fluorescein angiography (FA) or indocyanine green (ICG) angiography to visualize the blood vessels in the retina and choroid. On the day of treatment, eye drops will be instilled to dilate the pupils, which may cause blurred vision for several hours. It is advisable to arrange for someone to accompany you, as driving is not permitted after the treatment due to blurred vision. Tell the team about previous reactions to verteporfin or imaging dyes, porphyria, liver disease, all medicines, and any pregnancy or breastfeeding. These can affect whether the treatment is appropriate. The doctor will explain the procedure, potential risks, and post treatment instructions.

Verteporfin temporarily makes the skin and eyes sensitive to visible light. Follow the treating team's written instructions for how long protection is needed with the product you receive, and clarify the duration before leaving. During that period, avoid direct sunlight and intense indoor light such as tanning lamps or strong procedure lights. If you must go outside, cover the skin with protective clothing, a wide brimmed hat and dark sunglasses. Sunscreen alone does not protect against this reaction. Ordinary indoor light is safe, and you should not stay in complete darkness. Possible adverse effects include reactions at the infusion site, back or chest pain, allergic reactions and visual disturbances; occasionally vision can worsen significantly. Alert the team immediately to infusion site pain, breathing difficulty or other unexpected symptoms, and seek urgent assessment for worsening vision.

After treatment, mild blurred vision or light sensitivity may occur, usually resolving within minutes or hours. Adhering to light protection instructions is crucial. Follow up after treatment includes periodic eye examinations, which may involve OCT scans and other imaging tests, to assess the disease's response to treatment. In some cases, repeat treatments may be necessary to maintain results or address disease recurrence. You should contact your doctor if you experience sudden worsening of vision, severe pain, significant redness, or any other concerning symptoms.