Ophthalmic instrument and method of making ophthalmic determinations using Scheimpflug corrections

An ophthalmic instrument for aiding in determining the thickness and relative optical density of the cornea of an eye on a real-time basis, said instrument comprising:

• a) illumination means for illuminating a pre-selected area of the cornea of the eye in which the digitally encoded images are to be generated;
• b) slit projector means for illuminating a portion of the cornea of the eye;
• c) Scheimpflug correction means associated with said slit projector means for correcting plane of focus;
• d) television means for generating television images of the illuminated area of the cornea;
• e) converter means for converting the television images into digitally encoded images;
• f) processing means for receiving the digitally encoded images from the slit projector means and generating data used in the determination of the thickness and of the optical density of the cornea, said processing means generating the data related to the digitally encoded images at substantially the same time that the digitally encoded television images of the eye are being generated;
• and
• g) means for generating a display of the thickness and optical density of the eye from the data generated therefor.

An ophthalmic instrument for determining physical characteristics of an eye to aid in identifying exact and precise location of optical discontinuities and/or aberrations of the eye, said instrument comprising:

• a) a light projector means for illuminating a portion of an eye;
• b) electronic imaging means for obtaining electronic signal images of illuminated portions of the eye;
• c) slit means optically interposed between the light projector means and the electronic imaging means;
• d) means causing relative movement of the slit means relative to the eye to enable a plurality of slit image exposures of the eye during such relative movement and generation of the electronic signal images during such slit image exposures;
• e) means for shifting the plane of the slit means to obtain a correct focal plane and correct for parallax;
• and
• f) processing means receiving the electronic signals for processing the signals to identify discontinuities and optical aberrations of the eye.

A method for ascertaining the extent of an optical aberration or an optical discontinuity of tissue of the eye comprising the steps of:

• a) selectively illuminating the tissue area of the eye to be analyzed;
• b) moving an optical slit across the plane of the tissue area of the eye to be analyzed;
• c) adjusting the plane of the slit to obtain a Scheimpflug correction therefore;
• d) receiving and quantifying an image of the said tissue;
• e) delineating the portions of the image which contains the optical aberration or optical discontinuity and providing data representative therefor in electronic format;
• and
• f) analyzing the relative numerical magnitude of said electronic data to ascertain the severity of the optical aberration or optical discontinuity.