Design, construction and test of a surgical keratometer
- Resource Type
- article
- Authors
- Schor, Paulo; Campos, Mauro; Miller, David
- Source
- Arquivos Brasileiros de Oftalmologia. June 1998 61(3)
- Subject
- Cornea surgery
Instrumentation
- Language
- English
- ISSN
- 0004-2749
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.