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Biomedical subjects

C N Sims

Publications and source records attributed to C N Sims.

6 recordsLinked to original sources
PubMed1988

An evaluation of the photographs of William H. Crisp, MD.

The popularity of the Jackson cross cylinder is based on the assumption that its end points are "equal" to each other. Crisp's photographs, showing equal end points, popularized the Jackson cross cylinder technique. Photographs presented in this study show the anamorphic distortions of Snellen letters induced by the Jackson cross cylinder and suggest that Crisp's photographs were in error. His photographs do not represent the images seen by the patient when the Jackson cross cylinder refraction technique is used with Snellen letters.

Astigmatism↗
PubMed1982

Micronics and overrefraction.

Phoropter overrefraction, aided by a TI 58 or 59 calculator and programmed module, was evaluated as a routine procedure in 5,350 refractions. This technique provided increased patient acceptance of their glasses, better use of paramedical personnel, decreased refraction time, and improved cost efficiency of refracting. There was a 74% reduction of spectacle remakes and a 37.5 to 50% increase in refractions performed daily. This technique was compared to the previous 2,813 refractions using the conventional technique of refracting and to 2,600 refractions aided by an objective refractor. This study supports the thesis that overrefraction gives a higher degree of correlation of the images seen by the patient during the refraction procedure and the images seen with the final dispensed glasses. This correlation is possible because many of the variables in the refraction technique, refractor lens systems, or trial lenses, are reduced with the overrefraction technique.

Costs and Cost Analysis↗