Corneal topography: Photokeratoscopy including the central region
- 1 April 1993
- journal article
- Published by Wiley in Acta Ophthalmologica
- Vol. 71 (2) , 145-150
- https://doi.org/10.1111/j.1755-3768.1993.tb04980.x
Abstract
The central corneal zone is depicted on keratoscope photographs using a small target aperture and a large object distance. Information on the peripheral area is included by employing a hemispherical target with a dense circular and radial pattern. On a 16 mm (R = 8 mm) reference steel sphere the diameter of the innermost reflected mire is 0.20 mm and the distance between mires 0.13 mm. The standard deviation on focusing precision, determined to 0.20 mm employing a fixed object, corresponds to an error of 0.06% in linear measurements on keratographs. The variation in object distance due to the curved image plane is at most 0.55 mm within 60 deg from the optical axis of the system for the reference sphere. Nevertheless, all reflected mires are distinctly reproduced on the keratoscope photograph. For a test object the slopes of light intensity curves on the passage between black and white areas are reduced by only 1.0% with a variation in object distance of 0.55 mm around focus.Keywords
This publication has 9 references indexed in Scilit:
- Corneal topography: Photokeratoscopy including the central regionActa Ophthalmologica, 1993
- Corneoscopy in Keratorefractive SurgeryCornea, 1983
- Conventional Keratoscopy—A Critical ReviewClinical and Experimental Optometry, 1973
- Planar Reflected Imagery in Photokeratoscopy*Journal of the Optical Society of America, 1970
- PHOTOGRAPHIC ANALYSIS OF THE OCULAR DIOPTRIC COMPONENTS PART III. THE ACQUISITION, STORAGE, RETRIEVAL AND UTILIZATION OF PRIMARY DATA IN PHOTOKERATOSCOPYOptometry and Vision Science, 1967
- MEASUREMENTS OF THE OCULAR DIOPTRIC ELEMENTS UTILIZING PHOTOGRAPHIC METHODSOptometry and Vision Science, 1966
- CORNEAL CONTOURS IN THE GENERAL POPULATION AS REVEALED BY THE PHOTOKERATOSCOPEOptometry and Vision Science, 1961
- Zur Photographie der HornhautoberflächeAlbrecht von Graefes Archiv für Ophthalmologie, 1930
- VERGLEICHENDE MESSUNGEN DER FORM DER VORDEREN HORNHAUTFLÄCHE MIT OPHTHALMOMETER UND MIT PHOTOGRAPHISCHER METHODEActa Ophthalmologica, 1929