Micrometer-scale contact lens movements imaged by ultrahigh-resolution optical coherence tomography

To dynamically evaluate contact lens movement and ocular surface shape using ultrahigh-resolution and ultralong-scan-depth optical coherence tomography (OCT).

Clinical research study of a laboratory technique.

Four different types of soft contact lenses were tested on the left eye of 10 subjects (6 male and 4 female). Lens edges at primary gaze and temporal and nasal gazes were imaged by ultrahigh-resolution OCT. Excursion lag was obtained as the distance between the lens edge at primary gaze and immediately after the eye was quickly turned either nasally or temporally. The inferior lens edges were imaged continuously to track vertical movements during blinking. Ultralong-scan-depth OCT provided quantifiable images of the ocular surface, and the contour was acquired using custom software.

Excursion lag at the horizontal meridian was 366 ± 134 microm at temporal gaze and 320 ± 137 microm at nasal gaze (P > .05). The lens uplift at the vertical meridian was 342 ± 155 microm after blinking. There were significant differences in horizontal lags and vertical movements among different lenses (P < .05). Horizontal lags were correlated with radii of curvatures and sagittal heights at 6-mm and 14-mm horizontal meridian (P < .05). The blink-induced lens uplift first lowered by 104 ± 8 microm, and then lifted 342 ± 155 microm after the blink.

Ultrahigh-resolution and ultralong-scan-depth OCT can assess micrometer-scale lens movements and ocular surface contours. Both lens design and ocular surface shape affected lens movements.