Design, construction and test of a surgical keratometer

• Autor(a) principal: Schor,Paulo
• Data de Publicação: 1998
• Outros Autores: Campos,Mauro, Miller,David
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Arquivos brasileiros de oftalmologia (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0004-27491998000300346
• topic: Cornea surgery; Instrumentation

SUMMARY Objective: The presente study aims to draw, build and test a simple and low cost surgical keratometer. Methods: The principle described by Plácido da Costa was used to construct the prototype. A circular ring of light was built and attached to a surgical microscope. The zoom system present in the microscope provided a bigger or smaller image of the ring to the observer. lts size would then be compared to a circular reticle located inside the ocular lens of the microscope.Numeric values were achieved by a graduated scale. The flattest and steepest meridians were also located. Results: A precision between 0.29 and 0.62D h as been achieved in the evaluation of astigmatism. The meridian orientation showed a precision of about 10 degrees of inclination in astigmatisms greater than 1.60 D, and 6 degrees in astigmatisms greater than 1.96 D. Conclusion: This dévice showed a slightly inferior precision in astigmatism measurement, when compared to conventional surgical keratometers (0.10 to 0.25 D). Equal to high precision was observed when evaluating meridian location (conventional precision = 10 degrees). Itshould also be mentioned that its low cost and easy use may render it a very useful device.