Accurate eye-pressure readings guide glaucoma care. During and after the pandemic, clinicians wondered whether a surgical or KN95 mask pressed against the slit lamp could falsely raise Goldmann applanation numbers. A randomized study from Tel Aviv Sourasky Medical Center offers a reassuring average result—with an important patient-level caveat.
How the measurements were done
Ortal Fogel Tempelhof, MD, and colleagues studied 94 eyes of 47 glaucoma patients. Each eye’s intraocular pressure was measured twice with Goldmann tonometry under three randomized conditions separated by five-minute breaks: no mask, a surgical mask with ear loops, and a nonvalved KN95 mask.
Average vs individual results
- Average pressures differed by less than 0.5 mm Hg across scenarios (about 14.7 mm Hg with surgical masks and 15.1 mm Hg with no mask or KN95).
- No head-to-head pairing of mask conditions showed a statistically significant average difference.
- About 34% of patients still had a swing of at least 3 mm Hg between scenarios—large enough to matter for an individual treatment decision.
The authors pointed to mask fit, positioning under the slit lamp, and breathing pattern as likely reasons for person-to-person variation.
Clinic tips that help
- Sit still and breathe normally while the pressure is taken.
- If a reading seems unexpected, ask whether a repeat without a mask or a handheld check is reasonable before a medication change.
- Bring your mask preference up if you feel it pushes against the device.
One pressure number should rarely drive a major decision by itself. Trends, optic-nerve imaging, and visual fields complete the picture.
Putting one reading in context
Glaucoma decisions rest on patterns: optic-nerve appearance, retinal nerve-fiber imaging, visual fields, and a series of pressures—not a single afternoon number taken while a mask sat awkwardly against the tonometer. If two readings disagree, we repeat under consistent conditions before escalating therapy.
Khanna Vision Institute monitors glaucoma for Moorpark and Simi Valley patients at nearby offices. For more consumer-focused eye reading, visit lalasikcost.com.
Source: Face masks show no significant effect on average IOP readings in glaucoma (Healio Optometry, 10/12/2026). This article is an educational summary written by Khanna Vision Institute and is not a substitute for medical advice.