Differences in central corneal thickness between the paired eyes and the severity of the glaucomatous damage

Purpose To evaluate whether a difference in central corneal thickness (CCT) between the paired eyes could be associated to worse glaucoma in the thinner cornea eye.Methods From 16 different glaucoma centres, at least 50 glaucomatous patients were saved on the Italian Glaucoma Register. Eight hundred and sixteen glaucomatous patients were found in the register. CCT, ophthalmoscopic cup/disc ratio, mean deviation (MD), pattern SD (PSD), and intraocular pressure (IOP). The difference (Delta) between the paired eyes was calculated for all the considered parameters and two subgroups were created on the basis of Delta CCT. Because the difference between the two eyes could be positive or negative, the absolute value of Delta was considered for all the measurements. Three different Delta CCT cutoffs were selected: 10, 15, and 20 mu m. Student's t-test was used to compare the subgroups.Results When the entire group was divided in two subgroups using 20 mu m as Delta CCT cutoff, no significant difference was found for Delta IOP (-0.38 +/- 2.53 (mean +/- SD) mmHg and -0.07 +/- 2.35mmHg, respectively) between the two subgroups. Significant (P<0.001) difference was found for Delta MD (6.58 +/- 7.30 and 3.14 +/- 4.22 dB, respectively), Delta PSD (3.92 +/- 4.01 and 2.16 +/- 2.57, respectively), and Delta C/D (0.11 +/- 0.14 and 0.08 +/- 0.11, respectively) between the two subgroups. No significant correlation was found between Delta CCT and the other parameters.Conclusion The Delta CCT between the two eyes could be associated to a worse glaucoma in the thinner cornea eye.