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Graves' Orbitopathy


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Risk?

      In addition to the clinical assessments described in the section “How Do You Decide whether a Patient Has Dysthyroid Optic Neuropathy?”, several ancillary tests can also help to identify DON. These include visual-evoked potentials, contrast sensitivity and imaging.

      Abnormalities in both latency and amplitude of visual-evoked potentials can be supportive in the diagnosis of DON; however, several issues affect their value in practice. Firstly they can be affected by thyroid dysfunction, which is frequently present at the time when DON develops [13]. In addition, many laboratories have no normal data for patients over 60 years old, making it hard to interpret findings in those who are already the most difficult to diagnose due to confounding pathology [4]. Hence, they should be interpreted with caution in patients with no other evidence of DON.

      Contrast sensitivity, which measures spatial resolution at all levels of contrast, appears to be a sensitive indicator of DON [73]; however, it is less readily available and still subject to confounding pathologies.

      It is not necessary to perform any of these additional tests in all patients at every assessment. They can be very valuable when there are features suspicious for DON as described in “How Do You Decide whether a Patient Has Dysthyroid Optic Neuropathy?”, and, if abnormal, they may be useful for monitoring the response to treatment.