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In vivo ocular biomechanical compliance in thyroid eye disease
  1. Hans R Vellara,
  2. Richard Hart,
  3. Akilesh Gokul,
  4. Charles N J McGhee,
  5. Dipika V Patel
  1. Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
  1. Correspondence to Professor Dipika V Patel, Department of Ophthalmology, Private Bag 92019, University of Auckland, Auckland 1142, New Zealand; dipika.patel{at}


Background/aims To compare the ocular biomechanical properties in patients with thyroid eye disease (TED) and healthy participants using a non-contact Scheimpflug-based tonometer (CorVis ST).

Methods All eyes were examined by slit lamp biomicroscopy, corneal tomography and the CorVis ST (CST). Patients with TED were examined by a fellowship trained oculoplastics specialist to determine status and assess severity. The outputs from CST and additionally derived parameters, including maximum orbital deformation (MOD), were compared between healthy participants and patients with TED using Student's t-test. Furthermore, a multiple linear regression analysis was used to control for various factors known to influence ocular biomechanical responses to an air pulse.

Results This study included 20 patients with TED and compared them with a cohort of 152 healthy participants. The mean age of patients with TED was 46.7±19.0 years and the mean age of healthy participants was 35.9±13.8 years (p=0.03). There were no statistically significant differences in gender distributions between both groups (p>0.05). Several CST parameters were significantly different between groups (p<0.05). Of note, however, MOD was significantly lower in patients with TED (0.16±0.04 mm) compared with the healthy participants (0.25±0.05 mm, p<0.001). This dissimilarity remained even after controlling for the various cofactors. Receiver-operating characteristic analysis revealed an area under the curve of 0.91±0.04 (95% CI 0.84 to 0.98, p<0.001) for MOD.

Conclusions The in vivo ocular biomechanics as measured by the CST reflects a reduced orbital compliance. This method of ocular biomechanical assessment may aid in the categorisation of TED severity and assist in monitoring and/or diagnosing TED.

  • Imaging
  • Orbit
  • Diagnostic tests/Investigation
  • Eye (Globe)

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  • Contributors HRV was involved with the conception and design of the study, data acquisition, analysis and interpretation of data, and drafting of the manuscript. He is the guarantor of the paper. RH was involved with conception and design, data acquisition and revising the paper critically. AG acquired data and critically revised the paper. CNJM was involved with interpretation of the data, and critically revising the paper. DVP was involved with the conception and design, and interpretation of data, and critically revised the paper. All authors approved the final version to be published. All authors agree to be accountable for all aspects of the work and in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Competing interests None declared.

  • Ethics approval University of Auckland Ethics Committee (reference number 010853).

  • Provenance and peer review Not commissioned; externally peer reviewed

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