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Parekh and colleagues evaluated the safety, tolerability and diurnal IOP patterns obtained in patients with active thyroid eye disease (TED), using the Sensimed Triggerfish contact lens, a novel device sensitive to changes in corneal curvature and circumference. Intraocular pressure-derived corneal geometrical changes are captured by a strain gauge embedded within this unique contact lens. The generated electrical signals are transferred to a microprocessor, and then wirelessly transferred to a patched periorbital antenna and finally to a portable recorder. The device is set to capture 300 data points within a 30-second interval period, repeated every five minutes. Data is expressed in 'arbitrary units', hence, trends, peaks and circadian patterns can be identified, rather than actual IOP measurements in mmHg.
Recognizing patterns of IOP circadian rhythms may better assist in choosing the most appropriate therapy, as well as monitoring the success of therapies applied
In this prospective study, the more proptotic eye of ten TED patients was measured during a 24-hour interval. Safety was good, with only mild conjunctival hyperemia, occasional superficial punctate keratitis and blurred vision, all transient to the period the contact lens was placed on the eye. Tolerability was good, at 1.5 (on a 1-10 discomfort score). Of interest, three patients were measured both pre- and post-orbital decompression surgery. Regarding the circadian patterns observed, a peak was found at early morning (around 6:30 am) in half the patients. Analyzing the wake-sleep and sleep-wake transitions (which also coincide with the sitting-supine and supine-sitting postural changes) a notable change found was a significant decrease of the signal in the morning, transitioning from the sleep-supine to the wake-sitting position.
This study assists in identifying 24-hour IOP patterns in various secondary glaucomas and conditions known to affect the IOP. Recognizing patterns of IOP circadian rhythms may better assist in choosing the most appropriate therapy, as well as monitoring the success of therapies applied.