Purpose:
A new methodology to demonstrate the Corneal Endothelial Reserve (CER) and Corneal Endothelial Reserve Factor (CERF) for intraocular surgeries (IOS) and help to predict corneal decompensation.
Methods:
Corneal thickness (CT) was measured by paquimetry (μm), the normal values were used, from 350 to 700 μm. These values were correlated with all possible endothelial cell count (ECC) during the lifetime, measured by specular microscope, from 4000 to 350 cell.sq.mm. - Corneal Endothelial Reserve - CER: ECC/CT ratio was calculated by crossing the ECC during the lifetime with CT. Using these ratio values, a dispersion graphic was constructed with ECC in X-axis and ECC/CT ratio in Y-axis. The line of each CT used will be written in a different color and it will represent the patterns of each CT considering the ECC/CT ratio and ECC. The CER will be calculated by using the formula CER = ECC/CT - 1. - Corneal Endothelial Reserve Factor - CERF:CT/ECC ratio was calculated by crossing all CT with ECC during the lifetime. Using these ratio values, a dispersion graphic was constructed with ECC in X-axis and CT/ECC ratio in Y-axis. The line for each CT used will be written in a different color and it will resume the patterns of each CT considering the CT/ECC ratio and ECC. The distance from CT line, at level of ECC, to CT/ECC ratio = 1 determines the CERF. The values of CT/ECC > 1 was not used in the construction of the graphic because CT/ECC = 1 means the limit of endothelial function. CERF of corneal decompensation will be calculated by using the formula CERF = 1 - CT/ECC.
Results:
The CER formula and graphic are shown in Figure 1 and the CERF formula and graphic are shown in Figure 2.
Conclusions:
These graphic models and formulas are useful to calculate the CER and CERF for IOS, like cataract and intra-ocular refractive surgery.
Keywords: cornea: endothelium • cataract • refractive surgery