Hello and thanks for your question. The PDT laser that utilizes Visudyne is functionally altogether different from a thermal (or photocoagulative) laser that was used on your right eye. A photocoagulative laser uses heat to burn (and therefore destroy) a small area of the retina. As you know this is intended to cause the destruction of a small part of the retina; function follows form and if there is a larger than desired area destroyed by this laser, or this area happens to incorporate a part of the retina which is crucial for good central vision, then a loss of central vision can certainly result.
Thankfully, the PDT / Visudyne therapy is not a photocoagulative laser. Rather, the Visudyne is a light-activated molecule that when injected into the IV, and travels to the blood vessels in the retina, is activated by the particular wavelength of laser emitted by the PDT. This causes a chemical change in the structure of the molecule in Visudyne which fosters closure of abnormal blood vessels in the retina. But it is not photocoagulative in nature. Therefore the chances of you have significant vision loss from this PDT laser are much, much lower than the likelihood that a photocoagulative laser would cause vision loss.
Does this information help address your concerns? Does this make sense? Do you have any other concerns that I haven't addressed?
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My opinion is solely informative and does not constitute a formal medical opinion or recommendation. For a formal medical opinion and/or recommendation you must see an eye doctor.
You are correct; the use of Visudyne/PDT does not guarantee maintenance of vision. In it's safety and efficacy trials, Visudyne/PDT was found to be associated with a lower incidence of vision loss in certain types of lesions related to age-related macular degeneration (ARMD). The point that can be taken from this data is that there is a much more significant risk of the wet ARMD taking the vision than the PDT/Visudyne.
Yes, the use of Avastin and/or Lucentis does not utilize laser and therefore there is no risk of laser burns to the retina, period. However, they are also not benign treatments. The risk of overwhelming eye infection from these is still a concern. While many people just use Avastin and/or Lucentis to manage these lesions, it is possible that your doctor has found through experience that using this Triple Protocol has shown more demonstrable and predictable results with your particular type of lesion.
That being said, despite this information, if you still have significant concerns, there is nothing wrong with talking to your doctor and telling him/her that you would prefer to have just the Avastin or Lucentis injections for now. If you have been having them and there has not been a significant enough response, then that may be another reason why he/she would want to use this Triple protocol.
Fundamentally, though, the risk of vision loss with PDT/Visudyne as compared to photocoagulative laser is significantly lower. It does not approach zero, but then again none of these treatments are without risk of potential vision loss.
Does that make sense?
I'm sorry it has taken me so long to get back to you. I have been on an emergency call at the hospital. In two of the initial studies regarding PDT/Visudyne, there was a 1.4% incidence of what is called acute severe visual acuity decrease (ASVAD) in which only 10% regained some vision after this. This was usually seen in patients whose vision was 20/50 or better. So yes, there is some risk.
As far as a second opinion, I never think second opinions are a bad idea, especially when there is concern over the recommended treatments. It is a win-win situation; if the same treatment is recommended you can have more confidence in what is being recommended. If something different is recommended you have more information upon which to base your decision.