RT Journal Article
SR Electronic
T1 Impact factors on intraocular pressure measurements in healthy subjects
JF British Journal of Ophthalmology
JO Br J Ophthalmol
FD BMJ Publishing Group Ltd.
SP 1510
OP 1511
DO 10.1136/bjo.2004.049924
VO 88
IS 12
A1 T Theelen
A1 C F M Meulendijks
A1 D E M Geurts
A1 A van Leeuwen
A1 N B M Voet
A1 A F Deutman
YR 2004
UL http://bjo.bmj.com/content/88/12/1510.abstract
AB 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.