Colour versus grey-scale display of images on high-resolution spectral OCT.

AIM

To determine whether colour or grey-scale images from high-resolution spectral optical coherence tomography (OCT) are superior in visualising clinically important details of retinal structures.

METHODS

Patients with macular pathologies were imaged using spectral OCT (OTI, Toronto, Canada). Two reviewers independently analysed the retinal structures and pathologies and graded them on a four-point scale on the basis of the visibility. A third reviewer masked to the results then reviewed images where there was a different score for colour versus grey scale.

RESULTS

Statistical analysis showed the grey-scale image to be significantly better in visualising the details of epiretinal membrane, photoreceptor and retinal pigment epithelium layer morphology than the colour scale image (p = 0.00088-0.0006). In 16.17% of eyes, the colour image led to the false impression of photoreceptor disruption.

CONCLUSION

Grey-scale images are qualitatively superior to the colour-scale images on high-resolution spectral OCT. Colour images can be misleading, as the displayed colours are false colours, and the observer may see a dramatic change in colour and interpret that as a large change in the OCT reflectivity.