title: The Effect of a Diving Mask on Intraocular Pressure in a Healthy Population.
abstract: OBJECTIVE
  Swimming goggles increase the intraocular pressure (IOP) via the periorbital frame pressure and suction effect. In comparison, diving masks have a larger frame rim and incorporate the nose. The exact effect(s) of diving masks on IOP is unknown. This study evaluates the influence of diving masks on IOP in normal, healthy subjects.
  
  
  METHODS
  Tonometry was performed in both eyes of all subjects with an AVIA(®)Tono-Pen by a single investigator. Measurements were taken at baseline without the diving mask and with the subjects wearing a small-volume, double-window diving mask, but with the mask lenses removed. Two IOP readings in each eye were measured, and an additional reading was measured if the difference between the initial 2 was ≥2 mm Hg. Central corneal thickness (CCT) was also measured in each eye, using a contact pachymeter (OcuScan(®)Alcon).
  
  
  RESULTS
  Forty eyes of 20 healthy volunteers (age 29.7 ± 9.3 years; range 21-52) were included. The mean CCT was 544.4 ± 43.5 µm. The mean IOP before the diving mask was worn had been 17.23 ± 2.18 mm Hg (n = 40). The IOP decreased by 0.43 mm Hg (p $1003c; 0.05) to 16.80 ± 2.57 mm Hg after the diving mask had been put on. There was no correlation between IOP change and age (r = 0.143, p = 0.337), gender (r = -0.174, p = 0.283) or CCT (r = -0.123, p = 0.445).
  
  
  CONCLUSIONS
  There was no increase in IOP after the diving mask had been worn. A small but statistically significant decrease in IOP was observed. This study demonstrates that unlike swimming goggles, the strap tension and frame pressure on the periorbital tissue from a diving mask does not increase IOP. Diving masks may be a suitable alternative to swimming goggles for patients with advanced glaucoma or glaucoma filtration surgery.
authors.affiliation: Ophthalmology and Visual Sciences Department, Khoo Teck Puat Hospital, Singapore, Singapore.
authors.forename: Catherina Josephine
authors.initials: CJ
authors.lastname: Goenadi
authors.affiliation: National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore; Vision Performance Centre, Military Medicine Institute, Singapore Armed Forces, Singapore, Singapore.
authors.forename: David Zhiwei
authors.initials: DZ
authors.lastname: Law
authors.affiliation: Ophthalmology and Visual Sciences Department, Khoo Teck Puat Hospital, Singapore, Singapore.
authors.forename: Jia Wen
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Ophthalmology and Visual Sciences Department, Khoo Teck Puat Hospital, Singapore, Singapore.
authors.forename: Ee Lin
authors.initials: EL
authors.lastname: Ong
authors.affiliation: Ophthalmology and Visual Sciences Department, Khoo Teck Puat Hospital, Singapore, Singapore.
authors.forename: Wai Kitt
authors.initials: WK
authors.lastname: Chee
authors.affiliation: Ophthalmology and Visual Sciences Department, Khoo Teck Puat Hospital, Singapore, Singapore.
authors.forename: Jason
authors.initials: J
authors.lastname: Cheng
keywords: Diving mask; Glaucoma; Intraocular pressure; Swimming goggles