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Rupert R. Bourne, Zahra Jessa, Achilles Mandalos, Lydia Chang, Tim Quinnell, Rebecca Chadwick, John Shneerson; The Role Of Circadian Rhythm, Sleep Cycle And The Dark/light Environment In The Behaviour Of Twenty-four Hour Intraocular Pressure In Patients With Glaucoma. Invest. Ophthalmol. Vis. Sci. 2011;52(14):3447.
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To evaluate the role of circadian rhythm, sleep cycle and the dark/light environment in the behaviour of twenty-four hour intraocular pressure in patients with untreated glaucoma
Newly diagnosed patients with primary open angle glaucoma were recruited. Those with an irregular sleep pattern were excluded (actigraphy). To strengthen circadian synchronization, patients were asked to regularize their sleep periods for 7 days prior to admission to the sleep laboratory. Over a 24 hour period, two hourly measurements of supine IOP (pneumotonometer) were taken. Salivary melatonin was collected to establish dim light melatonin onset (DLMO). Lighting was dimmed to <30 lux between 18:00 and 07:00, with polysomnography (PSG) performed throughout the sleep period.
Four patients aged between 46-71 years were recruited. Considerable variation in standard deviation per eye (range: 1- 6mmHg) was noted with inconsistent timing of peak and trough IOP over 24 hours. Mean IOP during light phase (25.5mmHg) was higher than dark phase (21.6mmHg, P<0.001). No significant differences of mean IOP between the 3 circadian phases (light pre-DLMO/dim pre-DLMO/dim post-DLMO). During PSG, IOP was higher following a period of wakefulness than in slow wave sleep (SWS), while IOP measures between non-rapid eye movement (NREM) stages 2 and SWS were similar.
IOP reduction in dim light conditions was demonstrated but there was no association between IOP and circadian phase or stages of NREM sleep. Sleep-wake state may influence IOP. Wide inter-eye and inter-patient variation in IOP behaviour was observed. This study raises important questions about the interpretation of 24 hour IOP results which are important in the management of patients with glaucoma.
Clinical Trial: :
Cambridgeshire 1 Research Ethics Committee, 09/H0304/57
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