Abstract
Purpose:
To compare intraocular pressure (IOP) measurements obtained using Icare Pro rebound tonometer and Tono-Pen XL tonometer in supine and lateral decubitus body positions.
Methods:
One hundred eyes of 50 subjects (normal volunteers or glaucoma suspects) were enrolled in this prospective study. IOP was measured in both eyes using Icare Pro and Tono-Pen XL in the sitting position and the recumbent positions including supine, right lateral decubitus, left lateral decubitus. IOP was measured five minutes after assuming each of the recumbent postures in a randomized sequence. The eye on the lower side in the lateral decubitus position was termed as a dependent eye. Agreement of IOP readings between Icare Pro and Tono-Pen was assessed in all recumbent positions.
Results:
Icare Pro and TonoPen IOP readings showed good correlations in supine and lateral decubitus positions (all r>0.7, p<0.005), although Icare Pro readings were higher than Tono-Pen readings (all p<0.001) in all positions. The differences of IOP readings between two tonometers were weakly correlated with central corneal thickness in both eyes, whereas such a positive correlation was found only in the dependent eye in the lateral decubitus positions (r=0.307~0.531, all p<0.005). Both the spherical equivalents and axial lengths were not correlated with the differences between Icare Pro and TonoPen readings in all positions.
Conclusions:
IOP readings obtained with Tono-Pen and Icare rebound tonometer showed good agreement in supine as well as in lateral decubitus positions, although Icare readings were higher than Tono-Pen readings in all recumbent positions. Such differences in IOP readings between different tonometers need to be considered when measuring IOPs in various body positions.
Keywords: 568 intraocular pressure