Sleep Apnea and Intraocular Pressure: Effects of Continuous Positive Airway Pressure Treatment

Abstract

Abstract: : Purpose:To evaluate newly diagnosed sleep apnea patients for nyctohemeral variations of intraocular pressure (IOP) before and after continuous positive airway pressure (CPAP) treatment. Methods:Intraocular pressure of 12 sleep apnea patients without glaucoma was measured hourly throughout a 24h period before and after CPAP treatment. IOP was measured in upright position during daytime and in supine position during the night. Tonopen ^R, a portable tonometer which provides short measurements in any posture, was used. Polysomnography was performed simultaneously. Results:Before CPAP treatment, 4 patients exhibited a nyctohemeral rhythm of IOP encountered in glaucoma patients with mean values higher during the day than during the night. Five patients did not exhibit any 24–h IOP rhythm. Only 3 patients had a normal nyctohemeral rhythm of IOP, similar to the rhythm described in healthy subjects with mean values of IOP higher at night than during the day. After CPAP, among the 9 patients with abnormal rhythm before treatment, 6 subjects normalized their 24–h IOP rhythm (night > day IOP) and 3 patients remained unchanged (absence of 24–h rhythm). The 3 patients with a normal IOP rhythm before CPAP keep their individual rhythm similar after treatment. Conclusions:Sleep apnea is responsible for a change of the nyctohemeral rhythm of IOP. Continuous positive airway pressure treatment may normalize the abnormal rhythms associated with sleep apnea. Further studies are required to understand the association between sleep apnea and abnormalities of IOP nyctohemeral rhythm.

Keywords: intraocular pressure • circadian rhythms