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Cornea and thyroid eye disease: biomechanical alterations

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First Author: M.Vieira UK

Co Author(s):    A. Neves   F. Carvalheira   H. Arruda   A. Batista   J. Sousa        

Abstract Details

Purpose:

Thyroid eye disease (TED) is an extra thyroidal manifestation of Graves’ disease, closely linked to thyroid autoimmunity. TED is the most common cause of exophthalmos, with orbital biomechanical changes. Corvis ST is a non-contact Scheimpflug-based tonometer that perform the in vivo study of cornea biomechanics. The aim of this work is to understand the clinical application of Corvis ST in TED.

Setting:

Leiria Hospital Center, Portugal. Ophthalmology and Endocrinology department.

Methods:

For the study, 46/92 normal subjects/eyes, 18/36 with Graves' disease without ophthalmologic disease and 10/20 with TED were prospectively selected and examined with Corvis ST. Active TED was defined according to EUGOGO criteria. Statistic tests with Statistical Package for Social Studies (SPSS) were performed.

Results:

The mean age was 52.3±13.3 years-old, 71.6% females. TED's group had a significantly lower mean of curvature radius highest concavity (CRhc) (7.41±0.823 control's, 7.20±0.993 Graves', 6.78±0.704 TED's; p=0.012, mm) than control's (p=0.011). Active TED's (n=5/10, 6.77±0.885) had a lower mean of CRhc than Graves' (7.20±0.993, p=0.213) and inactive TED's (7.11±0.921, p=0.297). The mean of A1 length (mm) had significant differences among subgroups (p less than 0.0001). Active TED's had a significantly lower mean of A1 length (1.74±0.168, mm) than Graves' group (1.94±0.263, p=0.043) and inactive TED's (1.91±0.263, p=0.047). There are no differences in central corneal thickness nor in intraocular pressure.

Conclusions:

TED's group had a significantly lower CRhc and A1l mean, which denotes a more deformable cornea. Active TED's group had a significantly more deformable cornea than Graves' and inactive TED's group. So, active TED seems to have different corneal biomechanical properties that are independent of Graves' disease. One possible future approach is to prospectively follow TED's patients and perform repeated measurements of Corvis ST. For clinical practice, Corvis ST can be a valuable tool for the diagnosis of active TED screening. Besides the EUGOGO criteria for active TED, Corvis ST can possibly help to grade the severity of TED's disease.

Financial Disclosure:

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