Abstract
Purpose :
To investigate body position-related changes of anterior chamber angle (ACA) dimensions in normal, healthy eyes using anterior segment optical coherence tomography (AS-OCT) imaging.
Methods :
19 eyes of 19 healthy subjects aged 20 to 42 years old were imaged in supine and sitting positions using the Spectralis HRA+OCT and FLEX module (Heidelberg Engineering). The imaged eye (right or left) and order of body positions (seated and supine) were selected at random. One AS-OCT image along the horizontal meridian and one along the vertical meridian were acquired for each eye in both body positions. Pupil diameter (PD), trabecular iris angle (TIA), and angle opening distance (AOD) were measured using the manufacturer-provided image analysis program (Figure 1).Period-effect corrected differences between supine and seated TIA and AOD measures (as a ratio of the measure divided by PD) were analyzed. Significance was determined via a linear mixed model with a random intercept to account for intra-subject correlations.
Results :
10 subjects were imaged first in the seated and then in the supine position, and 9 subjects were imaged first in the supine and then seated positions. Age (34.5 + 6.2 and 32.9 + 7.5, respectively) and gender (F:M= 4:6 and 6:3, respectively) were similar between groups (P=0.618 and P=0.370). Period-effect corrected IOP was significantly higher by an average of 1.63mmHg in the supine position (P<0.001). In the nasal, temporal, superior and inferior quadrants, both period-effect corrected TIA and AOD were similar when comparing seated to supine, even when adjusting for pupil diameter (P>0.05 for all quadrants).
Conclusions :
There is no significant effect of body position on the dimensions of the ACA in young, healthy eyes.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.