To the Editor.
—The potential application of 193 nm of excimer laser radiation in refractive corneal surgery has been studied extensively, as this wavelength affects precise cuts with minimal adjacent thermal damage zones. One hundred ninety-three nanometers of excimer laser radiation has been shown to be cytotoxic1 and mutagenic.2 The potential hazards of secondary radiation effects to intraocular structures during 193-nm procedures have not been investigated up to now.We report here recent "ex vivo" measurements on bovine eyes that show that cataractogenic wavelengths around 305 nm reach the surface of the lens when the cornea is irradiated with 193-nm pulses of an excimer laser (MSC 102 Lambda Physic, Göttingen, West Germany). A quartz fiber (core 600 μm) was introduced into the eye so that the tip lay in front of the lens. The fiber output was focused onto the entrance slit of an optical multichannel analyzer (OMA