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 (Δ) between the paired eyes was calculated for all the considered parameters and two subgroups were created on the basis of ΔCCT. Because the difference between the two eyes could be positive or negative, the absolute value of Δ was considered for all the measurements. Three different ΔCCT cutoffs were selected: 10, 15, and 20 μm. Student's t-test was used to compare the subgroups. RESULTS: When the entire group was divided in two subgroups using 20 μm as ΔCCT cutoff, no significant difference was found for ΔIOP (-0.38 ± 2.53 (mean ± SD) mm Hg and -0.07 ± 2.35 mm Hg, respectively) between the two subgroups. Significant (P<0.001) difference was found for ΔMD (6.58 ± 7.30 and 3.14 ± 4.22 dB, respectively), ΔPSD (3.92 ± 4.01 and 2.16 ± 2.57, respectively), and ΔC/D (0.11 ± 0.14 and 0.08 ± 0.11, respectively) between the two subgroups. No significant correlation was found between ΔCCT and the other parameters. CONCLUSION: The ΔCCT between the two eyes could be associated to a worse glaucoma in the thinner cornea eye.