[The corneal biomechanical properties of patients with Graves' orbitopathy].

OBJECTIVE

This study aims to compare the corneal biomechanical properties of patients with Graves'orbitopathy (GO) with normal people and analysis the correlated factors.

METHODS

Retrospective case series study. 34 eyes of 20 patients (6 eyes are unilateral) diagnosed with inactive Graves' orbitopathy and 25 eyes of 14 patients (3 eyes are unilateral) diagnosed with active Graves' orbitopathy were recruited as study group. 30 eyes of 28 healthy volunteers with age and sex-matched were enrolled as control group in the affiliated eye hospital of Wenzhou medical university from December 2013 to June 2014. Central corneal thickness (CCT) measured with A ultrasound, corneal hysteresis (CH) measured with Ocular Response Analyser (ORA), corneal resistance factor (CRF), Goldman-corrected IOP value (IOPg) and Cornea-Compensated Intraocular Pressure(IOPcc) were collected. An ANONA and Kruskal-Wallis Test was used to compare the indexes mentioned above.

RESULTS

The mean age of inactive group was (47.3±12.8)y (23 eyes were female, 11 eyes were male), the mean age of active group was (51.9±9.6)y (16 eyes were female, 9 eyes were male) , the mean age of normal group was (47.2±10.4)y (19 eyes were female, 9 eyes were male). CH of inactive group was (9.68±1.45) mmHg, (1 mmHg=0.133 kPa), CH of active group was (9.82±1.53) mmHg, lower than the CH of (10.67±1.68) mmHg in control group, which was statistically significant different (t1=-2.51,P1=0.014,t2=-2.01,P2=0.048). IOPcc of inactive group was (17.91±3.67) mmHg, IOPcc of active group was (17.88±5.44) mmHg, which were higher than the IOPcc of (13.90±3.39) mmHg in the control group, which was statistically significant different (t1=3.76,P1=0.001;t2= 3.461,P2=0.001). There were no significant difference between study and control group in CRF, that was in inactive group (10.19±1.73)mmHg, active group (10.36±1.01)mmHg, normal group (10.08±1.40)mmHg respectively (t1=0.31,P=0.761;t2=0.69,P2=0.491). CCT of inactive group was (531.41±37.60) μm, CCT of active group is (533.52±18.88) μm, which had no statistical significant difference from the CCT of (546.25±28.84) μm in control group (t1=-1.91,P=0.059;t2=-1.52,P2=0.132). Corneal hysteresis was negatively correlated with exophthalmos, IOPg, IOPcc (Pearson=-0.279,-0.385,-0.663,P<0.05), and positively correlated with corneal central thickness and corneal resistance factor (Pearson=0.246,0.583,P<0.05) in TAO group.

CONCLUSIONS

Cornea hysteresis of TAO patients decreased, combined with lower ability of cornea to recover to the primary conditions when upon pressure. CH was negatively correlated with IOPg and IOPcc.(Chin J Ophthalmol, 2016, 52: 263-267).