To evaluate the effects of transient prone position on vault and anterior chamber angle parameters in ICL implanted patients.

40 eyes of 20 ICL implanted patients with at least 1 month of follow-up were included in the present study. The central ICL vault and anterior chamber parameters including angle opening distance at 500 (AOD500) were measured with the Visante anterior segment optical coherence tomography (OCT) (Carl Zeiss, Dublin, CA) in both the sitting and prone positions by tilting the OCT 90 degrees in the vertical axis and having the patient fixate downwards towards the floor.

The mean central vault was 0.55 ± 0.21 mm (SD) and 0.59 ± 0.21 mm (SD) in the sitting and prone positions, respectively ( p < 0.0001). The nasal and temporal AOD500 were 0.26 ± 0.11 mm and 0.28 ± 0.08 mm, respectively in the sitting position, which decreased to 0.24 ± 0.10 mm and 0.26 ± 0.08 mm in the prone position, however, both were not statistically significant ( p = 0.08, p = 0.09). AOD500 was inversely correlated with vault (r = -0.47; p = 0.0024). There were no significant correlations between increase of vault and anterior chamber depth or white to white nor ICL vault.

Transient prone positioning of ICL implanted patients can induce a significant increase in ICL vault.