Abstract
Purpose :
Eyes of glaucoma patients may be damaged during sleep. We conducted a prospective randomized interventional trial to test our hypothesis that wearing a protective eye shield or “mask” would reduce variability in and the magnitude of limbal strain experienced in glaucoma eyes when sleeping in a position with one side of the face down (FD), resting against a pillow. We also test our hypothesis that facial geometry influences responses to the FD position, and that in some individuals, facial features "mimic" the effects of the mask.
Methods :
The study was conducted at the Wilmer Eye Institute with 36 glaucoma patients. A contact-lens sensor (CLS) measured change in limbal strain (output in mVeq) during simulated sleep for intervals of up to 60 minutes in sitting, lateral-decubitus, FD (CLS-instrumented eye toward pillow) and supine positions. Eighteen subjects wore a mask during one of two FD intervals, with randomized assignment of the interval during which the mask was worn. Dimensions of 18 facial features were acquired from 3-D scanned images of 23 subjects.
Estimates of means, 95% confidence intervals and p-values for change in CLS with position are derived from Generalized Estimating Equation (GEE) linear models that take into account correlations among repeat measurements on a given participant.
Results :
Among all subjects tested without the mask, strain increased with FD posture and decreased with leaving FD (34.1 and -32.4 mVeq, respectively, p=0.01, 0.02, n=36). Wearing the mask reduced these changes by 22.3 and 34.5 mVeq each (p=0.09, 0.16). Including all subjects, wearing the mask reduced the variation in strain while FD (median difference in standard deviation = -22.8 mVeq, p=0.03, n=36). In study eyes with past progressive field loss, the mask reduced mean strain increase moving to FD by 44.8 mVeq (p=0.02, n=12). In contrast, eyes with no past field progression had only a 6.8 mVeq (p=0.68, n=19) increase moving to FD and no mask effect (p=0.73).
Preliminary analysis of facial scans suggests a longer distance from eye to nose tip reduces eye-pillow contact when FD. Statistical support for this was found in the CLS data on moving away from the FD position (p=0.04, n=23).
Conclusions :
Wearing a sleep mask reduced limbal strain and variation in limbal strain during simulated sleep in FD posture, particularly in eyes with progressive visual field loss.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.