Parallax-free exophthalmometry: a comprehensive review of the literature on clinical exophthalmometry and the introduction of the first parallax-free exophthalmometer

Stijn W Genders*, Daphne L Mourits, Mohammad Jasem, Roel J H M Kloos, Peerooz Saeed, Maarten Ph Mourits

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


PURPOSE: To present the first parallax-free exophthalmometer design.

BACKGROUND: Exophthalmometry is an important clinical tool. We provide a historic overview of clinical exophthalmometer designs, and we review current problems encountered in exophthalmometry.

METHODS: We present a new and parallax-free exophthalmometer design that we have evaluated in 49 patients visiting our orbital clinic.

RESULTS: The mean age of the patients was 49.8 years and 72% were female. The Pearson interobserver variation was 0.97, and 94% of the Hertel values measured by the two observers were within the limits (1.6 mm) of agreement.

CONCLUSION: This meter appears to be a reliable instrument for exophthalmometry. It is the first instrument that allows for a complete parallax-free measurement.

Original languageEnglish
Pages (from-to)23-9
Number of pages7
Issue number1
Publication statusPublished - Feb 2015


  • Diagnostic Techniques, Ophthalmological
  • Equipment Design
  • Exophthalmos
  • History, 19th Century
  • History, 20th Century
  • History, 21st Century
  • Humans

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