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In a prospective observational case series, Dar et al. evaluated the magnitude and duration of increase in intraocular pressure (IOP) during two principal Islamic prayer positions, Rukū (standing while bowing forward at a 90 degree angle), and Sujud (kneeling with forehead touching the ground) in 47 subjects including 68 eyes of healthy controls and 27 eyes of primary open-angle glaucoma patients (POAG). The Icare-Pro tonometer (Icare, Tiolat Oy, Helsinki, Finland) was used to measure IOP after 30 seconds of each prayer position with an interval of five minutes between the two. Final IOP was recorded in sitting position immediately after Sujud position and repeated after five minutes in case it did not reach within 2 mmHg of baseline IOP.
The main fallacy in IOP measurements was that IOP was not measured in the exact prayer positions but with the participant's head rotated 45 degrees in the direction of the eye being measured. Additionally baseline IOP was not measured prior to the second prayer position.
The IOP rise was similar in healthy controls and POAG with an increase of 20% from baseline value of 16.1 ± 2.9 mmHg (8.6-26) to 19.3 ± 4.2 mmHg (10.2-32.3) following 30 seconds of Rukū (p ≤ 0.0001) and by 37% following Sujud from 16.1 ± 0.4 mmHg to 22.2 ± 3.1 mmHg (14.9-37) (p ≤ 0.0001). 73% eyes returned to baseline when IOP was checked immediately after the prayer position and all eyes returned to baseline values when IOP was rechecked after five minutes.
Transient rise in IOP in POAG and healthy individuals has previously been well documented with head down YOGA postures with return to baseline values within two minutes of assuming a sitting posture.1 A rise in episcleral venous pressure and choroidal congestion are the main mechanisms for these pressure spikes.
A rise in episcleral venous pressure and choroidal congestion are the main mechanisms for these pressure spikesThe present study highlights that transient rise in IOP can occur during traditional Muslim prayer positions. However, the authors conclusion that these findings may have a considerable impact on Muslim patients with glaucoma and put the patients at risk of disease progression is an overstatement which cannot be inferred based on the present study.
Head down positions may have a concomitant rise in cerebrospinal fluid pressure and this may diminish the trans-lamina cribrosa gradient giving a compensating counter-pressure against the rise in IOP.
Nevertheless, the present study lays the foundation for designing a randomized trial to study whether head down postures increase the risk of developing glaucoma or its progression.