Purpose:
Exophthalmometry is a common adjunctive tool for diagnosing and evaluating progression of thyroid eye disease (TED). TED patients may exhibit asymmetric eye proptosis from periorbital tissue inflammation. To our knowledge, there has been no assessment of orbital compliance in TED. This study aims to quantify differences in orbital compliance between TED and non-thyroid eye disease (NTED) patients by Hertel exophthalmometry taken in a sitting and supine position.
Methods:
TED patients and randomly selected NTED patients from the Yale Eye Center underwent exophthalmometry. The distance between the corneal apex to the lateral orbital rim were recorded in a sitting position, in a supine position immediately after reclining, and in a supine position after 5 minutes. The 5 minutes allows for equilibrium of orbital compliance. TED and NTED measurements were divided into three categories to account for differences in anatomical characteristics those with sitting measurements <18 mm (category 1), 18-21 mm (category 2), and >21 mm (category 3). The difference between sitting and supine measurements was used to represent orbital compliance, and was analyzed statistically in each category. A single physician took all measurements using a calibrated Hertel exophthalmometer.
Results:
44 NTED and 52 TED eyes were measured. A statistically significant reduction in TED globe recession, when compared to NTED eyes, was measured immediately after reclining or after 5 minutes in a supine position. A statistically significant reduction in TED globe recession was also seen immediately after reclining in categories 1 and 2 and after lying supine 5 minutes in categories 2 and 3 (Table 1).
Conclusions:
Decreased globe recession in TED orbits compared to NTED orbits suggest reduced orbital compliance in TED patients and may be a useful adjunct in the clinical assessment of TED patients.
Keywords: orbit • comparative anatomy