Impact factors on intraocular pressure measurements in healthy subjects
- Correspondence to: Thomas Theelen, MD Department of Ophthalmology, University Medical Centre Nijmegen, Philips van Leijdenlaan 15, 6525 EX Nijmegen, Netherlands; t.theelenohk.umcn.nl
- Accepted 14 June 2004
Abstract
Aim: To evaluate whether intraocular pressure (IOP) calculation by applanation tonometry is determined more essentially by the subject’s neck position or by neck constriction.
Methods: 23 right eyes of 23 healthy subjects (12 male, 11 female) were included. IOP was measured by applanation tonometry with the TonoPen on sitting participants under four different conditions: with open collar upright (A) or with the head in the headrest of a slit lamp (B), with a tight necktie upright (C) or in slit lamp position (D). All measurements with neck constriction were performed 3 minutes after placing the necktie.
Results: Mean IOP was 16.9 (SD 2.3) mm Hg (range 11–21 mm Hg) (A), 18.1 (SD 2.2) mm Hg (range 14–22 mm Hg) (B), 17.9 (SD 2.9) mm Hg (range 12–25 mm Hg) (C) and 18.7 (SD 2.7) mm Hg (range 13–24 mm Hg) (D). Mean IOP increased by 1.3 (SD 2.6) mm Hg (p = 0.028, paired t test, range +0.2 to +2.4 mm Hg) if subjects changed position from A to B. There was no statistically significant difference between measurements with or without neck constriction.
Conclusion: Applanation tonometry may be inaccurate if performed in slit lamp position. In contrast, tight neckties do not significantly affect IOP evaluation in healthy subjects.
- BCVA, best corrected visual acuity
- BMI, body mass index
- IOP, intraocular pressure
- NC, neck circumference
- intraocular pressure
- BCVA, best corrected visual acuity
- BMI, body mass index
- IOP, intraocular pressure
- NC, neck circumference
- intraocular pressure
Footnotes
-
↵* The authors wish to be known that, in their opinion, the first two authors should be regarded as joint first authors.
-
The authors have no proprietary or financial interest in this study.
-
Presented in part as a poster at the 198th meeting of the Dutch Opthalmologic Society, Amsterdam, Netherlands, March 2004, and at the congress of the European Glaucoma Society, Florence, Italy, June 2004.
