Can we measure the intraocular pressure when the eyeball is against the pillow in the lateral decubitus position?

Purpose: To evaluate the amount of intraocular pressure (IOP) change in the eye against the pillow in the lateral decubitus position (LDP). Methods: Thirty eyes from 15 healthy volunteers (12 men and three women) aged 293 (range 25-37) years participated in this study. Using the rebound tonometer (Icare PRO, Icare Finland Oy, Helsinki, Finland), the IOP of both eyes was checked in sitting, supine, right and left LDPs. In the LDP, the additional IOP measurements were taken with the lower eyeball against the latex pillow. Results: Baseline IOP in the sitting position was 12.7 +/- 1.9mmHg in the right eye and 12.8 +/- 2.2mmHg in the left eye. Ten minutes after shifting from the sitting to the supine position, IOP increased significantly (right eye: +1.4 +/- 1.4mmHg, p=0.006; left eye: +1.8 +/- 1.5mmHg, p=0.001). Changing from the supine to the right and left LDP increased significantly the IOP of dependent eye (right eye: +2.3 +/- 1.8mmHg, p=0.001; left eye: +1.5 +/- 1.8mmHg, p=0.011). When the dependent eye was compressed against the pillow in the LDP, the IOP of the dependent eyes increased significantly after 10min (right eye in the right LDP: +4.1 +/- 4.9mmHg, p=0.011; left eye in the left LDP: +3.4 +/- 3.7mmHg, p=0.006). Conclusion: The IOP was significantly elevated when the eyeball was against the pillow in the LDP.