Shadow photogrammetric apparatus for the quantitative evaluation of corneal buttons

D. Denham, S. Mandelbaum, J. M. Parel, S. Holland, S. Pflugfelder

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We have developed a technique for the accurate, quantitative, geometric evaluation of trephined and punched corneal buttons. A magnified shadow of the frontal and edge views of a corneal button mounted on the rotary stage of a modified optical comparator is projected onto the screen of the comparator and photographed. This process takes approximately three minutes. The diameters and edge profile at any meridian photographed can subsequently be analyzed from the film. The precision in measuring the diameters of well cut corneal buttons is ±23 microns, and in measuring the angle of the edge profile is ±1°. Statistical analysis of inter observer variability indicated excellent reproducibility of measurements. Shadow photogrammetry offers a standardized, accurate, and reproducible method for analysis of corneal trephination.

Original languageEnglish (US)
Pages (from-to)794-799
Number of pages6
JournalOphthalmic surgery
Issue number11
StatePublished - Dec 1 1989

ASJC Scopus subject areas

  • Ophthalmology


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