Abstract
Purpose::
Endothelial cell analysis and cell counting have been routinely performed for over 30 years. Over this time period, instrumentation and methods have been improved to allow rapid measurements relating to the state of the corneal endothelium. Unfortunately, an understanding of the errors of the various methods available and the number of cells needed to obtain a valid cell count has been lacking so that the results of may studies is suspect. We present improved methods that eliminate these problems and suitable for use today and in the future.In the earlier times, when field sizes were small, it was known that often the number of cells counted was insufficient to obtain a truly valid measure of the endothelium as a whole. In addition, methods of cell counting were used that had large inherent counting errors. For both reasons it was often unclear how valid the cell counts were and whether the validity could be improved by including more cells in the sample.
Methods::
Software for acurate, rapid, and automatic endothelial cell counting has been combined with software for statistical analysis of the number of cells needed for valid results and the confidence levels for the analysis.
Results::
We have developed, and will discuss, software that works together to enable an accurate, rapid, and automatic measurement of cell count for corneal endothelial images and then determines if, and how many, additional measurements from multiple images must be pooled to obtain a valid measure of cell count that applies to the endothelium as a whole, or to the endothelial region of interest. The software not only tells us how many cells are needed but also provides confidence levels and other information useful in evaluating the corneal endothelium. This software system can be used on essentially any specular microscope to provide accurate, rapid, and valid measures of cell count and other parameters for endothelial analysis.
Conclusions::
An improved method for obtaining accurate and reliable endothelial cell count and cell analysis values is now available that provides better information about the status of the corneal endothelium that what has been available up to now.
Keywords: cornea: endothelium • imaging/image analysis: clinical • imaging/image analysis: non-clinical