keratometry การใช้

• Keratometry is especially important in the fitting of rigid lenses.
• This is due to an increase in the refractive power of the keratometry readings do not reveal a corneal or length basis for a myopic shift . It is usually reversible with time.
• People that are considered for treatment must undergo an extensive clinical workup, including corneal tomography, computerized corneal topography, endothelial microscopy, ultrasound pachymetry, b-scan sonography, keratometry and biomicroscopy.
• A development of keratoscopy, corneal topography extends the measurement range from the four points a few millimeters apart that is offered by keratometry to a grid of thousands of points covering the entire cornea.
• The constant is a theoretical value that relates the lens power to AL and keratometry, it is not expressed in units and is specific to the design of the IOL and its intended location and orientation within the eye.
• Therefore, it is important that tests assessing shape of the cornea, such as keratometry and corneal mapping, be performed prior to tonometry . Slit lamp and applanating prism used in Goldmann tonometryIn Goldmann tonometry, a 3.06mm plastic tonometer tip attached to a slit lamp is pressed onto an anaesthetised cornea with fluorescein.
• Manifest refraction is the familiar test where the eye doctor rotates various lenses in front of the eye, asking the patient, " Which is better ( or clearer ), this one or this one ? " Corneal topography is considered a more quantitative test, and for purposes of aligning a toric IOL, most surgeons use a measurement called simulated keratometry ( SimK ), which is calculated by the internal programming of the corneal topography machine, to determine the astigmatic meridian on the surface of the cornea.