Determination of Endothelial Cell Density by Specular Microscopy by Manual and Automated Methods in Normal and Pathologic Corneas

Lee, Olivia

Determination of Endothelial Cell Density by Specular Microscopy by Manual and Automated Methods in Normal and Pathologic Corneas

Tuesday, April 29, 2014: 8:50 AM

Room 154 (Boston Convention and Exhibition Center)

Olivia L. Lee, MD, University of Southern California, Los Angeles, CA, USA

Cristina Modak, PhD, Doheny Eye Institute, Los angeles, CA, USA

Jyotsna Maram, PhD, Doheny Eye Institute, Los Angeles, CA, USA

Vikas Chopra, MD, University of Southern California, Los Angeles, CA, USA

Narrative Responses:

Purpose
To compare specular microscopy grading methods in normal and pathologic corneas.

Methods
Central images were prospectively captured from 3 controls and 3 patients with corneal endotheliopathies using Konan’s NSP-9900 microscope. Endothelial cell density (ECD) was measured using the CellChek Analysis Software. Images were graded independently by multiple masked graders using manual Center and Flex Center methods, as well as machine-generated AutoTrace method. Absolute error < 5% in ECD value was considered acceptable agreement. ECD variation across the same visit was used as internal control.

Results
95 images were analyzed. In controls, 42% of ECD values obtained by AutoTrace (mean 2846 +/- 263 cells/mm2) versus Center Method (mean 2791 +/- 249 cells/mm2)were in agreement, however, this was not statistically significant (p=0.40). In patients with mild corneal endotheliopathy, AutoTrace ECD values (mean 2617 +/- 106 cells/mm2) were in agreement with manual Center method counts (mean 2250+/-275 cells/mm2) in 17% of cases (p<0.05). Flex Center and Center agreed in all cases of mild endotheliopathy. In cases with moderate to severe guttata, no difference in ECD values was observed between manual methods (p=0.63) but neither method agreed with AutoTrace (p<0.05).

Conclusion
In normal corneas, both automated and manual methods may generate reproducible ECD values. However, in cases of endothelial pathology, AutoTrace may overestimate ECD values and should be used with caution. Center and Flex Center methods are preferable in their ability to produce reliable ECD values in compromised or diseased endothelium.