Improved contrast microscopy: modification of bright field for urine sediment visualisation.

BACKGROUND: Phase contrast microscopy is the recommended technique for urine sediment examination. Bright field microscopy does not differentiate objects with slight changes in the refractive index and hence phase contrast is a superior alternative.

METHODS: In this article, we describe a novel method to improve contrast in bright field microscopy. A strategically placed disc of specific dimensions enhances the diffraction of rays by Fresnel principle causing a shift in wavelength in the rays which are perceived as differences in contrast by the eye due to constructive and destructive interference.

RESULTS: Epithelial cells, red blood cells (RBCs), dysmorphic red blood cells, casts, bacteria and crystals are easily seen and differentiated by this technique.

CONCLUSIONS: The images obtained are similar to those obtained by phase contrast microscopy.