Abstract
Purpose: :
To describe a simple method for rapid screening for exophthalmos (XO). Background: Frontal visual assessment of XO is often hindered by alterations in periocular soft tissues i.e. droopy lids or brows or redundant tissue. While quantitative methods for assessing XO are well established, they have significant limitations for screening detection of XO which is a key feature in the diagnosis of Thyroid Eye Disease (TED). They are expensive and require training. The vast majority of patients in whom XO is being detected are intially seen by non-specialists who neither own nor use the devices. Finally, due to individual biologic and ethnic variation, the use of absolute quantitative standards for identification of XO in TED is now being abandoned by expert groups. There is a great need for a rapid screening test for XO, employable by non-specialists to allow for people with suspected early TED to be identified and referred for appropriate diagnosis and treatment.
Methods: :
40 consecutive patients with suspected XO were studied following informed consent. Frontal periocular photographs(FP) and Hertel exophthalmometry (HXO) were performed and photographs were taken from the patient's sides in 3 ways. First simple lateral photographs (LP), 2nd LPs with a straightedge aligned with the midpoint of the brow and oriented vertically resting gently on the periocular soft tissue (LP1), 3rd as LP2 but with the straightedge pressed firmly posteriorly resting on the orbital rim (LP2). Brow XO (XOB) was defined as intersection of the line extending from the posterior edge of the straightedge with the cornea surface during LP1 or LP2.The frontal and lateral photographs were then presented to ophthalmologists in random order for assessment of whether XO was present.
Results: :
FP had the lowest detection rate for XO, followed by LP, then LP1. LP2 had the highest detection rate of XOB. Eyelid malpositions and soft tissue changes appeared responsible for the low detection rate by FP. Differences in LP1 and LP2 were seen in cases with significant periocular soft tissue. LP2 detected clinically documented thyroid associated XO in some cases when HXO measurements were well below "accepted gender and ethnic based numerical values".
Conclusions: :
This study demonstrates that lateral is superior to frontal assessment for detection of XO. Brow based exophthalmometry, while not quantitative, can be more sensitive than HXO using demographic based values in detecting clinically significant XO and is thus a useful screening test. BXO like other XO methods has less value with extreme variations in orbit anatomy. Numerical changes in XO are best done with HXO.
Keywords: orbit • eyelid • face perception