24-hour monitoring gives insights on circadian rhythm of IOP before and after SLT

Issue: April 10, 2017

Continuous 24-hour monitoring of IOP showed that the majority of patients with primary open-angle glaucoma have a nyctohemeral IOP rhythm with nocturnal acrophase. It also demonstrated that selective laser trabeculoplasty significantly lowers pressure but does not alter the nyctohemeral IOP rhythm.

The prospective study was conducted in a sleep laboratory affiliated with the University Hospital of Grenoble, France, and included 14 patients with primary open-angle glaucoma. The Triggerfish contact lens sensor (Sensimed) was used for continuous 24-hour IOP monitoring before SLT and then at 1 month and 6 months after SLT treatment. All three monitoring sessions were preceded by a washout procedure to thoroughly eliminate any bias effect from medications. For 1 month before placing the lens, treatments were replaced with one drop twice a day of dorzolamide (Alcon), which was discontinued 1 week before lens placement.

After the washout procedure, mean IOP increased by 5.8 mm Hg. A statistically significant decrease of 3.4 mm Hg and 1.88 mm Hg was achieved after SLT at 1 month and 6 months, respectively. The 24-hour monitoring was successfully conducted, showing that 100% of the patients had a circadian IOP rhythm with significant day-night variations, in which the acrophase was at night. The curve characteristics remained substantially unaltered at 1 month and 6 months after SLT.

Besides the small size of the study, a limitation might be that SLT was performed over 180° of the trabecular meshwork. The authors hypothesized that 360° SLT treatment might have different effects, possibly leading to significant changes in the circadian IOP rhythm. – by Michela Cimberle

Disclosure: The authors report no relevant financial disclosures.

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Source:

Aptel F, et al. J Glaucoma. 2017;doi:10.1097/IJG.0000000000000604.