Abstract
Purpose:
To investigate the relationship between 24-hour IOP-related patterns recorded with a contact lens sensor (CLS) in patients with PAC and PACG before and after LPI.
Methods:
A single center, prospective, open label study was to recruit 30 patients with PAC and PACG, of Indian origin. This reports describes the initial findings of the first 6 eligible patients in the ongoing clinical study. Eligible patients underwent 24-hour IOP-related pattern recording using a CLS, on a outpatient basis, in the same eye before (pre-) and 1 month after (post-) LPI. The CLS, that measures spontaneous dimensional changes of the eye at the corneoscleral area (SENSIMED Triggerfish®, Sensimed, Switzerland), was used to record the IOP-related pattern for 24 h in the habitual position. The CLS was placed, after comprehensive ophthalmic examination, including IOP (Goldmann applanation tonometry). Pre- and post-LPI CLS pattern variability was determined for the diurnal, nocturnal and 24-hour periods. Diurnal and nocturnal periods were defined as patients’ wake and sleep periods, respectively, as determined by the lack of blinking during each CLS recording session. Cosine amplitude, time of acrophase and variability were compared between pre-and post-LPI using parametric tests paired t-tests, with level of significance set at α=0.05.
Results:
Six eligible patients were analyzed with a mean age of 57.2±10.3 years (66.6% female). All patients were of Indian origin. The mean IOP was 20.0±3.3 mmHg pre-LPI and 19.5±3.9 mmHg post-LPI, a non-significant reduction of 1.6% (0.33±2.0 mmHg). A statistical trend for reduction the overall number of IOP-related peaks (p=0.052) and throughs (p=0.058) was observed post-LPI as compared to pre-LPI. The number of nocturnal troughs was significantly reduced post-LPI (p=0.004). The amplitude and time of acrophase of the pre- and post-LPI cosine of the CLS output did not differ significantly. A reduction of 11.8 mVeq was observed post-LPI. The amplitude and corresponding time of acrophase was 141.9 mVeq at 03:25 am and 130.1 mVeq with acrophase at 03:34 am, respectively.
Conclusions:
Despite unchanged IOP, the CLS-recorded 24-hour IOP-related pattern provides clinically relevant information with respect to the chronobiology of IOP fluctuation in patients with PAC and PACG after LPI.
Keywords: 568 intraocular pressure •
468 clinical research methodology