Photodynamic therapy (PDT) eiiploying Dihematopor*iyrin ethers (DHE)
(Photofrin II) at pharmacologic lvels, has been denonstrate3 to kill rabbit
lens epithelial cells, in vivo. This in vitro study, reports on the
minimal necessary parameters for rabbit lens epithelial cell death.
Explants of rabbit lenses were incubated in various concentrations of
DHE (1O,, 100, 500, 1000 ug/ml) for 1, 2, or 5 minutes. 30 to 120
Joules/an of collimated 514.5 nm Argon laser light re delivered to the
locier concentrations of 10, 50, and 100 ug,'ml DHE treated cells. One
hundre1 fifteen explants were treated, in all.
Higher concentrations of DHE alone (500 and 1000 ug/ml) were
sufficient to induce cellular swelling. Lower concentrations required light
for cellular effect. Trypan blue staining revealed cell death at these
minimal pa9ieters: DHE 50 ug/ml, incubation 1 minute, 514.5 r Argon light
1.0 Watt/an for 30 sec (30 Joules) . In future studies, these rameters
will be tested in vivo, for their ability to eliminate lens epithelial
proliferation after cataract surgery.