title: Hypoxic Corneal Changes following Eight Hours of Scleral Contact Lens Wear.
abstract: OBJECTIVE
  To examine the change in corneal thickness and posterior curvature following 8 hours of miniscleral contact lens wear.
  
  
  METHODS
  Scheimpflug imaging (Pentacam HR; Oculus) was captured before, and immediately following, 8 hours of miniscleral contact lens wear for 15 young (mean age 22 ± 3 years), healthy participants with normal corneae. Natural diurnal variations were considered by measuring baseline corneal changes obtained on a separate control day without contact lens wear.
  
  
  RESULTS
  Over the central 6 mm of the cornea, a small but highly statistically significant amount of edema was observed following 8 hours of miniscleral lens wear, after accounting for normal diurnal fluctuations (mean ± standard deviation percentage swelling 1.70 ± 0.98%, p < 0.0001). Posterior corneal topography remained stable following lens wear (-0.01 ± 0.07 mm steepening over the central 6 mm, p = 0.60). The magnitude of posterior corneal topographical changes following lens wear did not correlate with the extent of lens-related corneal edema (r = -0.16, p = 0.57). Similarly, the initial central corneal vault (maximum post-lens tear layer depth) was not associated with corneal swelling following lens removal (r = 0.27, p = 0.33).
  
  
  CONCLUSIONS
  Although a small amount of corneal swelling was induced following 8 hours of miniscleral lens wear (on average <2%), modern high Dk miniscleral contact lenses that vault the cornea do not induce clinically significant corneal edema or hypoxic-related posterior corneal curvature changes during short-term wear. Longer-term studies of compromised eyes (e.g. corneal ectasia) are still required to inform the optimum lens and fitting characteristics for safe scleral lens wear to minimize corneal hypoxia.
authors.affiliation: *PhD, FAAO †PhD ‡BVisSc Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Kelvin Grove, Brisbane, Queensland, Australia (all authors).
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Vincent
authors.forename: David
authors.initials: D
authors.lastname: Alonso-Caneiro
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Collins
authors.forename: Alison
authors.initials: A
authors.lastname: Beanland
authors.forename: Linda
authors.initials: L
authors.lastname: Lam
authors.forename: Ching Chong
authors.initials: CC
authors.lastname: Lim
authors.forename: Alyssa
authors.initials: A
authors.lastname: Loke
authors.forename: Nhi
authors.initials: N
authors.lastname: Nguyen
mesh_terms: D000293:Adolescent; D000328:Adult; D000869:Anterior Eye Segment / Q000473:pathology; D003261:Contact Lenses / Q000009:adverse effects* / Q000706:statistics & numerical data; D003315:Cornea / Q000473:pathology; D015715:Corneal Edema / Q000209:etiology*; D063171:Corneal Pachymetry; D019781:Corneal Topography; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D008297:Male; D013997:Time Factors; D055815:Young Adult