Abstract
Purpose: :
To compare corneal endothelial cell images from non contact specular and confocal microscopy by cuantitative and cualitative analysis.
Methods: :
A prospective, descriptive and comparative study was made. Eighty corneas of forty healthy subjects without ocular pathology were examined using a non contact specular microscopy Topcon SP 2000 P (Topcon Corp., Tokio, Japan) and confocal microscopy using Confoscan 3 (Nidek Technologies, Advanced Vision Information System) Ver 3.4.1. Fifty cells were included in Manual and automatic cell count in confocal (the square area in average was 0.232 mm) as well as in specular microscopy, the images were analyzed by selecting the center of the cells. All results obtained were calculated automatically by the computer. The images of corneal endothelium obtained by the two techniques were evaluated: endothelial cell density (manual and automatic mode) minimum cellular size, maximum cellular size, average cellular size, standard deviation and pleomorfism were compared. SPSS (SPSS, Inc., Chicago Il) was used to compute descriptive statistics. Statistical comparison of the values between two methods were using a Wilcoxon signed rank test.
Results: :
In specular microscopy the results were: endothelial cell density 2311 +/–143 cel/mm², minimum cellular size average 225 µm², maximum cellular size average 831µm², average cellular size 441µm² and pleomorfism 31%. In confocal microscopy endothelial cell density were: 2818 +/–16 cel/mm², minimum cellular size average 185 µm², maximum cellular size average 756 µm², average cellular size 363 µm² and pleomorfism 44%. The differences between the confocal and specular were in average variations of 380 cells (14%). In manual and automatic mode of confocal microscopy, the variations were in average 819 cells (30%). When comparing both assessment methods there was a statistical significant difference (p<0.000) in all evaluated variables.
Conclusions: :
There is a statistical significant difference between corneal endothelium images obtained by the two techniques, the results are not compared. In this study we do not recommend the use for one instead another method for the analysis of corneal endothelial cells, it would be selected on basis of the advantages of the both methods and the clinical information.
Keywords: cornea: endothelium • imaging/image analysis: clinical • microscopy: confocal/tunneling