Abstract: An apparatus having a first generator designed to produce a first beam of coherent light, the energy of which is concentrated in a succession of impulses each capable causing a microexplosion in organic tissue at the point to be treated, a second generator designed to produce a second beam of coherent light able to penetrate the thickness of this organic tissue, an optical system designed to focus the first or the second beam on the point to be treated and a beam switch able to selectively direct the first or the second beam towards the optical system. The second beam enables ophthalmologists to perform operations that could not hiterto be performed with know apparatuses, notably operations involving the penetration of a treatment beam into the thickness of the tissues of the eye.