To investigate intraocular pressure (IOP) and ocular biometry change according to the posture change in healthy eyes.

Forty eight eyes of 48 healthy young subjects were enrolled. IOP, central anterior chamber depth (cACD), and axial length were measured after keeping each position for 10 minutes (upright, sitting, supine, and prone positions) by using the TonoPen® and A-scan ultrasonography.

Mean IOP was 19.68 ± 2.15 mm Hg in prone position, 17.19 ± 1.33 mm Hg in supine position, 16.49 ± 1.76 mm Hg in sitting position, and 15.33 ± 1.34 mm Hg in upright position. Difference among the positions was statistically significant ( p < 0.01). Mean cACD was 3.68 ± 0.35 mm in upright position, 3.63 ± 0.32 mm in supine position, 3.59 ± 0.34 mm in sitting position, and 3.47 ± 0.30 mm in prone position. Difference among the positions was statistically significant ( p < 0.01) except for the difference between supine and sitting position. Linear regression analysis revealed that cACD was significantly associated with IOP in prone position (R² = 0.139, p < 0.01).

There was a significant change in IOP and cACD according to the posture change. cACD was significantly associated with IOP only in prone position.