Effect of overnight wear of the Triggerfish® sensor on corneal thickness measured by Visante® anterior segment optical coherence tomography

Purpose To evaluate the effect of overnight wear of the Triggerfish((R)) contact lens sensor (CLS) on central corneal thickness (CCT) using the Visante((R)) anterior segment optical coherence tomography (AS-OCT). Methods Twelve healthy subjects were studied in a sleep laboratory. An ophthalmic examination including ultrasonic CCT, corneal topography, specular microscopy and AS-OCT CCT was performed. Starting at 7pm, the Triggerfish((R)) CLS was fitted on one randomly selected eye. Similar AS-OCT measurements were taken on both eyes every 2hr from 8pm to 8am. The CLS was removed just after the 8am measurement session. Measurements were repeated at 9am. Results Twenty-four eyes of 12 subjects were studied (mean age, 22.1 +/- 2.4years; four men/eight women). CCT significantly increased during the night in both CLS and control eyes (p<0.01). The maximal change was +4.4 +/- 1.7% in the CLS eyes and +2.9 +/- 1.8% in the control eyes (p<0.05). Throughout the night, CCT significantly increased more in eyes with CLS than in control eyes (p<0.05). There were significantly more corneal curvature irregularities after overnight wear of the CLS than in the control eye: +1.63Dioptre (D) versus -0.02D in the 3-mm central zone and +3.17D versus +0.01D in the 5-mm central zone (p<0.01). Conclusion CCT and corneal curvature irregularities increased slightly but significantly more in eyes with the Triggerfish((R)) CLS than in control eyes during overnight wear. Further studies are required to determine whether the corneal curvature changes modify the signal recorded by the sensor.