Photodynamic therapy is a procedure used in the treatment of some eye conditions. Its introduction in the ophthalmology field began with treating age-related macular degeneration (AMD) before its present effective use in central serous retinopathy (CSR).
AMD consists of the dry and wet AMD, but the procedure treats only specific types of wet AMD. Both CSR and the wet AMD have the potential to damage vision in severe cases due to fluid leaks into the retina from blood vessels.
CSR typically affects people aged 55 and below, with most of them being males, whereas AMD affects the older age group. Photodynamic therapy combines the use of laser light and a photosensitive drug known as verteporfin. The combination works to minimize vision damage by sealing blood vessels to stop leakages.
Also Known As
- Blue light therapy
Before the Procedure
The patient needs to understand several things before agreeing to the treatment. Some of them include:
- The reason for the treatment
- Risks and benefits of the procedure
- The date and cost of surgery
- The expected outcome with and without the procedure
Patients can inquire from the doctor on whether they should refrain from any ongoing medication or foods before the procedure. After consent from the patient, the doctor may conduct eye tests that may involve dilating the eyes. S/he may also take weight and height measurements to determine the correct amount of verteporfin medicine.
On the day of surgery, the patient should wear well-covering clothes and carry sunglasses and a hat, to prevent skin exposure to light. Patients need to organize for someone to drive them home as they would be unable to do so with blurry and dilated eyes.
Photodynamic therapy, in most instances, takes place as an outpatient procedure in an eye hospital. The patient is usually awake during the entire period. The doctor will first inject photosensitive medicine in the patient's arm.
After receiving the injection, a caregiver will direct the patient to a chair specially designed for the procedure. At this point, the patient receives drops of local anesthesia to numb the eye and prepare it for treatment.
The doctor waits for a few minutes, then places a special contact lens in the eye and focuses it on the laser light. The patient may feel a bit of discomfort but no pain. The ophthalmologist will then carefully position the laser to direct light to the exact target spot.
The laser light combines with the verteporfin to clump blood, thereby sealing the vessels. After the treatment is done, the doctor removes the contact lens, and s/he may cover the eye temporarily.
Risks & Complications
The procedure has associated risks and complications which may vary across patients. The differences could be because of age or some medical conditions. Among the risks are skin inflammation resulting from a reaction with verteporfin, and development of a new blind spot.
A significant side effect of the treatment is photosensitivity of the eyes and skin. Other effects include:
- Temporary vision changes such as blurry vision, decreased vision, or flashes
- Pain on the injected area
- Eyelid irritation
- Nauseous feeling
- Pain in the back or joints during the injection. However, the pain fades moments after the infusion ends.
Some AMD patients may experience a critical reduction in vision. The complication may result from either a shutdown of normal blood vessels or disruption of pigment layers during treatment. CSR patients rarely experience a severe decrease in vision since ophthalmologists use half the dose of the photosensitive medicine.
Aftercare & Recovery
The photosensitive medicine, in most instances, causes the eye and skin to be sensitive to light. Therefore, the patient should stay indoors while keeping away from direct sunlight. In unavoidable circumstances, they should wear dark sunglasses for the eyes and clothes that will not expose the skin to light.
Some types of house lights, such as from halogen bulbs, may pose risks to the skin and should be avoided.
To ease the soreness that may occur later, the patient may use over the counter painkillers. The doctor may also prescribe other medications and further instructions on eye care, such as minimal touching and rubbing. Patients should take medicine as per the doctor's advice. Ice packs on the injected area may help to minimize swelling.
Follow up visits to evaluate progress may be necessary. During these visits, the patient should notify the doctor about worrying issues such as constant pain, severe swelling and redness, or reduced vision.
Most of the side effects fade after about two days, but patients may be able to continue with normal indoor activities even the next day. One should consult with their doctor on when it would be safe to resume outdoor activities.
Photodynamic therapy does not restore vision but helps to reduce further damage that may result in blindness. A good number of patients go through the process successfully with effective outcomes. However, the sealed blood vessels may keep opening up, prompting a need for retreatment.