Pre-treatment using a xanthin carotenoid (preferably 3R,3'R-zeaxanthin)
can improve the benefits and efficacy of photodynamic therapy (PDT),
which uses a light-activated drug (such as verteporfin) in patients who
suffer from unwanted retinal blood vessel growth, including the "wet"
(exudative) form of macular degeneration. Before a PDT treatment,
patients are given a regimen of orally-ingested zeaxanthin for a period
of at least 1 and preferably at least 2 to 3 weeks, at dosages of at
least 3 and preferably at least 10 milligrams per day. Since zeaxanthin
imparts a yellowish color to the macula, a preferred dosage should
increase a patient's macular pigment density before the PDT treatment is
performed.
