title: Rates of visual acuity change in patients receiving hyperbaric oxygen in monoplace and multiplace chambers.
abstract: BACKGROUND
  Changes in visual acuity are a known side effect of hyperbaric oxygen (HBO₂). We conducted a quality improvement initiative to better quantify visual change risk and to identify possible risk factors.
  
  
  METHODS
  Vision was checked weekly in a clinical HBO₂ population by Snellen eye chart. Visual acuity change was defined as Snellen test worsened to 20/40 or greater or by loss of 2 lines.
  
  
  RESULTS
  Of 85 patients treated from January 2013 to February 2015 with 10 HBO₂ sessions and ≥ 2 weeks of visual acuity testing, 53 (62%) were male. All were treated for UHMS-approved indications. A total of 34 patients (40%) had no change in visual acuity, 27 (32%) had a 1-line change, and 24 (28%) had at least a 2-line worsening in visual acuity. The number of sessions for those with at least a 2-line change was 36 ± 15 (15-60). A 2-line change occurred at similar rates for monoplace and multiplace patients (29% and 32%, respectively), but monoplace patients more frequently reached 20/40 or worse (32% vs. 18%). Seven of 11 patients with existing cataracts had ≥ 2 line change, as did six of 14 patients (43%) with a history of head/neck radiation.
  
  
  CONCLUSIONS
  In this retrospective review of quality improvement data, 28% of patients had a 2-line change in visual acuity by Snellen exam after treat-ment with HBO₂. Further study of possible risk factors, including chamber type, is warranted.
authors.forename: Susan
authors.initials: S
authors.lastname: Churchill
authors.forename: Kayla
authors.initials: K
authors.lastname: Deru
authors.forename: Gail
authors.initials: G
authors.lastname: Wilson
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cable
authors.forename: James E
authors.initials: JE
authors.lastname: Bell
authors.forename: Lindell K
authors.initials: LK
authors.lastname: Weaver
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000175:diagnosis / Q000209:etiology*; D058996:Quality Improvement; D012189:Retrospective Studies; D012307:Risk Factors; D014787:Vision Tests; D014792:Visual Acuity