Relationship between tear eotaxin-2 and matrix metalloproteinase -9 with ocular allergy and corneal topography in patients with keratoconus

Introduction and Aim: To analyze the relationship between the presence of ocular allergy and tear eotaxin-2 and matrix metalloproteinase (MMP)-9 levels and corneal topoography in patients with keratoconus. Material and Methods: The study was held in Yıldırım Beyazıt University Atatürk Education and Training Hospital, Keratoconus and Refractive Surgery Center between March 2016 and June 2016. Thirty-four eyes of 34 keratoconus patients without ocular allergy (Group 1), 34 eyes of 34 keratoconus patients with ocular allergy (Group 2) and 20 eyes of 20 subjects without any ocular problem rather than refractive error were enrolled in the study. Detailed ophthalmological examination and corneal topography measurements including keratometry 1 (K1), K2, mean K, maximum K, corneal astigmatism, central corneal thickness, thinnest corneal thickness were performed in all subjects. Questionnaires were asked about the presence of any ocular allergy. Tear samples were collected by Schirmer method. After extraction of tear samples from Schirmer strip, tear eotaxin-2 and MMP-9 levels were measured by the ELISA method. Topographic and tear parameters were compared between the groups. Results: There were no significant difference between gender and age between groups (p=0.77, p=0.16, respectively). The difference between the topographical parameters between group 1 and 2 was not significant (p=1.0). The stages of the disease were similar between the kerotoconus groups (p=0.59). The mean tear eotaxin-2 level was higher in group 2 when compared to the contol and group 1 keratoconus patients but the difference was not statistically significant (p=0.17). The mean tear MMP-9 levels of all keratoconus patients were significantly higher than the control group (p=0.004). Tear MMP-9 level showed a positive correlation with the stage of the keratoconus and a negative correlation with the thinnest corneal thickness (r=0.29 p=0.018, r=-0.30 p=0.006, respectively). Conclusion: Tear MMP-9 level was higher in advance stages of keratoconus patients with thinner corneas. However tear eotaxin-2 level was similar between the keratoconus patients and the normal eyes. Both MMP-9 and eotaxin-2 levels did not correlated with the corneal topographical findings. The role of MMP-9 in keratoconus etiopathogenesis was mainly on the corneal thickness. Further studies investigating new treatment approches based on the protease enzymes should be performed for prevention and treatment of keratoconus. Key Words: Keratoconus, Ocular allergy, Corneal topography, Eotaxin-2, Matrix metalloproteinase-9