Poor imaging can give inaccurate readings of nerve fiber loss in the cornea. As such, researchers have developed a three-pronged quality index for corneal confocal microscopy imaging to help reduce variability in corneal nerve parameter analysis.

The study, published in Cornea, reviewed images from 75 participants, including 25 in each of the three image quality groups. Researchers analyzed corneal nerve fiber length using automated and semi-automated software and corneal nerve fiber density and corneal nerve branch density through automated image analysis. Three masked raters assessed the corneal confocal microscopy image quality independently and categorized the images into the three groups.

Researchers found corneal nerve fiber length, corneal nerve fiber density and corneal nerve branch density increased significantly with the quality index. Additionally, corneal nerve fiber length was reported to be higher using semi-automated nerve analysis than automated nerve analysis, independent of the quality index.

“The quantification of corneal nerve parameters depends on image quality, and poorer quality images are associated with lower values for corneal nerve parameters,” researchers said in their paper.

The quality index could be a useful tool to reduce variability in quantification of corneal nerve parameters, they added.

Sturm D, Vollert J, Greiner T, et al. Implementation of a quality index for improvement of quantification of corneal nerves in corneal confocal microcopy images: a multicenter study. Cornea. April 11, 2019. [Epub ahead of print].