Ophthalmic range finding

Embodiments of the invention provide methods and systems for analyzing the ophthalmic anatomy of a patient posterior to the cornea. The method may include scanning a focus of a femtosecond laser beam along a path within the patient's eye. A portion of the path may be disposed posterior to the patient's cornea. The method may also include acquiring a first reflectance image and a second reflectance image associated with the focus disposed respectively at a first location of the path and a second location of the path. The method may further include determining the presence or absence of an ophthalmic anatomical feature of the eye based on a comparison between the first reflectance image and the second reflectance image.