A Protective Eye Shield Reduces Limbal Strain and Its Variability during Simulated Sleep in Adults with Glaucoma

Alison Flatau, Francisco Solano, Joan L. Jefferys, Christopher Damion, Harry A Quigley

Research output: Contribution to journalArticle


Purpose:To determine the effect of wearing a protective eye shield (mask) on limbal strain magnitude and variability in glaucoma eyes when sleeping with 1 side of the face down (FD) against a pillow.Methods:A prospective, randomized, interventional trial was conducted at the Wilmer Eye Institute with 36 glaucoma patients. A contact lens sensor measured limbal strain (output in equivalent millivolts) during intervals of up to 60 minutes in lateral decubitus, FD, and supine positions. Eighteen subjects wore a mask during 1 of 2 FD intervals, with randomized assignment of the interval. Data from additional trials with no mask were included in some analyses. In addition, some facial-feature dimensions from 3D scanned images of 23 subjects were compared with limbal strain data.Results:Wearing a mask trends toward a reduced mean change in contact lens sensor output (limbal strain) on moving to a FD positions [+34.1 mVeq, P=0.01 reduced by -22.3 mVeq, P=0.09 (n=36)]. Mask wearing reduced variability in strain while FD [-22.8 mVeq, P=0.04 (n=18)]. In eyes with past progressive visual field loss, the effect of the mask reduced mean strain change when moving to FD [-44.8 mVeq, P=0.02 (n=31)]. Longer corneal apex to nose-tip and to temple lengths were associated with reduced variability while FD [P=0.02 and 0.04, respectively (n=23)]. Treating both lengths as confounding factors increased statistical significance, particularly for analysis of the no-mask change in strain data moving to and from the FD position [P=0.004 to 0.002 and P=0.03 to 0.01 (n=23)].Conclusion and Relevance:Wearing a mask reduced limbal strain and variation in limbal strain during simulated FD sleep, particularly in eyes with past field worsening, as did some facial features.

Original languageEnglish (US)
Pages (from-to)77-86
Number of pages10
JournalJournal of Glaucoma
Issue number1
StatePublished - Jan 1 2018


  • glaucoma
  • intraocular pressure
  • limbal strain
  • protective eye shield

ASJC Scopus subject areas

  • Ophthalmology

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