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

Abstract

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 (D) between the paired eyes was calculated for all the considered parameters and two subgroups were created on the basis of DCCT. Because the difference between the two eyes could be positive or negative, the absolute value of D was considered for all the measurements. Three different DCCT cutoffs were selected: 10, 15, and 20 mm. Student's t-test was used to compare the subgroups. Results When the entire group was divided in two subgroups using 20 mm as DCCT cutoff, no significant difference was found for DIOP ( À 0.38 ± 2.53 (mean ± SD) mm Hg and À 0.07 ± 2.35 mm Hg, respectively) between the two subgroups. Significant (Po0.001) difference was found for DMD (6.58 ± 7.30 and 3.14 ± 4.22 dB, respectively), DPSD (3.92 ± 4.01 and 2.16±2.57, respectively), and DC/D (0.11±0.14 and 0.08±0.11, respectively) between the two subgroups. No significant correlation was found between DCCT and the other parameters. Conclusion The DCCT between the two eyes could be associated to a worse glaucoma in the thinner cornea eye. Keywords: glaucoma; central corneal thickness; visual field damage; difference between eyes IntroductionAs glaucoma is a chronic asymmetric progressive degenerative disease of the optic nerve head, most patients with glaucoma can have a different stage of the disease between the two eyes.Although central corneal thickness (CCT) measurements are usually highly symmetric between paired eyes, approximately 6-7% of individuals do manifest significant interocular CCT asymmetry. 1-3 CCT has been identified as a substantial glaucoma risk factor, 4-8 and glaucomatous damage often presents in an asymmetric fashion. 9,10 The percentage of normal-tension and hightension glaucoma patients with unilateral VF loss has been estimated to be approximately 25-35%. 9 Asymmetric CCT was already associated with asymmetric primary open-angle glaucoma (POAG) in a retrospective study. 11 In a later study by the same group, however, asymmetric POAG was associated with asymmetric dynamic contour tonometry but not Goldmann applanation tonometry or CCT. 12 The aim of the study was to evaluate whether a difference in CCT between paired eyes could be associated to worse glaucoma in the thinner cornea eye. Patients and methodsThis is a retrospective, cross-sectional study. Institutional review boards and ethics committees at the institutions gave their approval of this study. This study followed the principles of the Declaration of Helsinki.From 16 different glaucoma centres, at least 50 glaucomatous patients for each centre were saved on the Italian G...

The Relationship Between the Sighting Eye and Functional and Structural Asymmetries in Glaucoma

“…Solid lines and black circles: group 1; dashed lines and white circles: group 2. and peripapillary atrophy, which are characteristic features associated with myopia, affected the asymmetry of glaucomatous damage between eyes. 16,20 In accordance with previous studies, we found that the MD of the worse eyes were associated with structural parameters such as cup-to disc ratio, average RNFLT, and average GCIPLT (Table 4).…”

Major review: Molecular genetics of primary open-angle glaucoma

“…This is consistent with the long-held belief that damage to components of the aqueous outflow pathways by reactive oxygen species (ROS) contributes to elevated IOP, a common feature observed in POAG (Siegfried et al, 2015). In other studies a correlation between CCT, optic nerve head topography, and visual field damage was found (Cankaya et al, 2008; Coman et al, 2014; Iester et al, 2012; Insull et al, 2010; Kaushik et al, 2006; Mokbel and Ghanem, 2010; Pakravan et al, 2007; Papadia et al, 2007; Saenz-Frances et al, 2015; Sullivan-Mee et al, 2005). The relationship between POAG risk and CCT is complex and poorly understood.…”

Central Corneal Thickness Measurement in Sub-Saharan Africa: Review

“…In Brazil, the mean CCT for PCG patients was 534 ± 72.3 μm [55]. According to Italian Glaucoma Register, the CCT between the two eyes (Right 545.68 ± 35.82 µm, Left 546.89 ± 36.09 µm) could be associated to a worse glaucoma in the thinner cornea eye [56]. In Lithuania, CCT were 540 ±64μm, this value in the glaucoma group were statistically significant [46].…”