Corneal Biomechanical Alterations in Patients with Chronic Ocular Graft Versus-host Disease

PurposeTo compare corneal biomechanics between patients with ocular graft versus-host disease (oGVHD) and healthy subjects (controls), and to further correlate these values with ocular and hematological characteristics. Materials and MethodsThe following procedures were performed in oGVHD patients and controls: Schirmer test (ST), break-up time (BUT), corneal and conjunctival staining, tear matrix metalloproteinase-9 (MMP-9) assay (InflammaDry test, Rapid Pathogen Screening, Inc, Sarasota, FL). Corneal biomechanics were calculated by using ocular response analyzer (ORA, Reichert Instruments, Depew, New York, USA). The Mann-Whitney U test was used to compare continuous variables between oGVHD patients and controls. Correlations of corneal biomechanics with ocular and hematological parameters were examined using Spearmans correlation. ResultsA total of 45 oGVHD patients (mean age {+/-} SD, 51.5 {+/-} 7.1 years) and 34 controls (47.8 {+/-} 6.1 years) were included. Patients with oGVHD showed significantly lower values of corneal hysteresis (CH) and corneal resistance factor (CRF) compared to controls (respectively, 9.4 {+/-} 1.8 mmHg vs 11.6 {+/-} 1.6 and 9.7 {+/-} 1.4 mmHg vs 12.3 {+/-} 1.3; always p<0.001). Twenty-nine of the oGVHD eyes (64.4%) were strong-positive for MMP-9, while 16 (35.6%) were weak-positive. Conversely, only 4 of the control eyes (11.8%) were weak-positive for MMP-9. In patients with oGVHD, CH was significantly correlated with corneal staining (Rs = -0.316, p = 0.035), conjunctival staining (Rs = -0.437, p = 0.003), ST (Rs = 0.390, p = 0.008), BUT (Rs = 0.423, p = 0.004), oGVHD severity grade (Rs = -0.383, p = 0.009), and MMP-9 positivity grade (Rs = -0.429, p = 0.003), while CRF was correlated only with corneal staining (Rs = -0.317, p = 0.034). ConclusionsCorneal biomechanics are reduced in patients with oGVHD, and CH is negatively correlated with disease severity grade and MMP-9 tear levels.