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Graves' Orbitopathy


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target="_blank" rel="nofollow" href="#ulink_a37039cf-9415-5acc-b596-7ec9d87f5cb7">57] by using a bowl or arc perimeter, with mean excursions shown in Table 4. An age-related decline in excursions, especially elevation, has been noted by some but not all studies [56, 57, 61]. What does not appear to be useful in assessing or monitoring muscle function is imaging. Neither MRI volumes nor ultrasound correlate with muscle function, clinical course, or subjective diplopia [6265].

      5.Corneal pathology: While minor corneal pathology requires slit-lamp examination to detect punctate fluorescein staining, sight-threatening pathology is evident with simple torch examination. In this situation, the eyelids do not close gently to cover the cornea, which remains visible. The lower conjunctiva is generally red, and if ulceration has developed, a grey opacity or even an abscess will be seen in the inferior cornea. This constitutes an emergency.

      6.Visual disturbance: Clinical assessments for DON comprise the following:

      (a)best-corrected visual acuity of each eye, which is most accurately measured with a logMAR chart, although Snellen charts are more widely available;

      (b)colour vision testing in the blue/yellow axis is most likely to pick up early defects of DON; however, red-green pseudo-isochromatic charts (e.g., Ishihara) are more readily available and remain very useful in this context (see the section “How Do You Decide whether a Patient Has Dysthyroid Optic Neuropathy?”). Each eye is tested separately using a reading correction as required;

Lateral rectus (0°) (abduction) 46.2a to 52b
Superior rectus (67°) 43b
Elevation centrally (90°) 33.8a
Inferior oblique (141°) 46b
Medial rectus (180°) (abduction) 47.5a to 51b
Superior oblique (216°) 49b
Depression centrally (270°) 58.4a
Inferior rectus (293°) 62b
By convention, ocular excursions away from primary fixation (gaze straight ahead) are designated as 0° for pure abduction, i.e., right gaze for the right eye and left gaze for the left eye. The degrees for each gaze direction follow from this reference point such that they increase in a clockwise direction for the right eye and an anticlockwise direction for the left.
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      (c)pupil responses are assessed by the swinging flashlight test for a relative afferent pupil defect; artefacts can easily be produced if a consistent method is not followed, particularly in patients with manifest strabismus; the patient fixates on a distant target, and care is taken to give both eyes equal stimulation with the same alignment to the visual axis while the light is moved between alternate eyes;

      (e)perimetry is reserved for eyes with suspicion of DON; automated perimetry is most commonly used.

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      Both UFOF and BSV measurements show high levels of accuracy with UFOF repeatable to within 8° for single muscle measurement [56], and BSV fields accurate to within 4%.

      The reproducibility of assessments for DON is unknown.