Abstract: An ophthalmic diagnostic method and apparatus measures the distance between the corneal surface and the fundus of an eye being examined by projecting a beam of coherent light at the eye and varying the wavelength of the coherent light while observing differences between the optical paths of two light waves reflected by the cornea and the eye fundus. The differences are based on the length of the optical axis of the eye and observed as a phase difference between the two light waves. The length of the optical axis of the eye being examined can be measured from the amount of change in the measured phase difference corresponding to the variation in wavelength, enabling the length of the optical axis of the eye to be measured without mechanical control.

Abstract: A base fabric for a pressure-sensitive adhesive tape comprising as the warp a flat yarn of polyester fibers containing a specific residue in the molecular chain. A pressure-sensitive adhesive tape obtained from this base fabric is easy to tear in the crosswise direction and has a smooth torn edge.