Abstract
Purpose :
To evaluate corneal biomechanical changes in patients with p.Ala546Asp mutation in the TGFBI gene, using the Corvis ST (Oculus, Wetzlar, Germany).
Methods :
A Mexican family with history of granular corneal dystrophy type 2 (GCD2) underwent genetic testing. All available members went through a slit-lamp exam and a corneal biomechanical evaluation using Corvis ST. Patients were divided in to three groups. Family members with mutation and clinical GCD2 (group 1, n=8), family members with mutation with no clinical corneal dystrophy changes (group 2, n=3) and a control group (group 3, n=20). Exclusion criteria for the control group included corneal alterations in tomography/slit lamp and history of ocular surgery. Biomechanical corneal stiffness was determined using the Corvis Biomechanical Index (CBI), which uses data from the deflection amplitude ratio, integrated radius, Ambrosio relational thickness horizontal and stiffness parameter-A1. Statistical analysis was performed with an unpaired T-Test and Tukeys range test.
Results :
Ten out of 15 were mutation positive (p.Ala546Asp) patients. 8 out of these were available for further testing. One patient was excluded from the study for having a history of corneal transplant. Group 1 had a mean CBI of 0.63, group 2 had a mean CBI of 0.58, group 3 had a mean CBI of 0.12. The difference in CBI between groups 1 and 2 was not statistically significant (p=0.729). The difference in CBI between groups 1 and 2 with group 3 (control group) was statistically significant (p<0.0001). The difference in CBI between group 1 and 3 was also statistically significant (p<0.0001). The difference in CBI between group 2 and 3 was also statistically significant (p<0.0001).
Conclusions :
Patients with the p.Ala546Asp mutation in the TGFBI gene have more elastic corneas than patients without this mutation. The fact that group 2 also had a statistically significant difference in CBI with the control group suggests that the mutation itself alters corneal biomechanics, independently of corneal amyloid deposits in granular corneal dystrophy type 2.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.