title: Corneal changes after suspending contact lens wear in early pellucid marginal corneal degeneration and moderate keratoconus.
abstract: OBJECTIVE
  This case study reports on how refraction, visual acuity, and ocular higher-order aberrations changed after rigid gas-permeable (RGP) lens wear was suspended by a patient with early pellucid marginal corneal degeneration (PMD) and by a patient with moderate keratoconus. Alterations in central corneal power and axes, central corneal thickness, and corneal topography were also explored.
  
  
  METHODS
  Ocular aberrations and Scheimpflug photography were measured at 2 visits, 7 days apart, after the patients had removed their contact lenses. Subjective refraction and logarithm of the minimum angle of resolution visual acuities were also recorded at both visits.
  
  
  RESULTS
  In contrast to the keratoconic patient, the patient with early PMD showed changes in subjective refraction (approximately -1.75 diopter cylinder of astigmatism), front surface central powers (∼1.3 diopter [D] horizontally and 2 D vertically), and anterior surface topography (∼1.2 D) between visits. Both patients showed an increase in total higher-order root mean square (HORMS) aberrations after suspending lens wear (∼0.40 μm for the moderately keratoconic patient and 0.22 μm for the early PMD patient).
  
  
  CONCLUSIONS
  Changes in the optical and structural parameters of the cornea after suspending lens wear are likely to be dependent on a multitude of factors, such as the lens fitting and the biomechanical properties of the cornea. The findings of this report may be useful to practitioners when refracting or refitting existing RGP lens wearers with ectasia or to those involved in prescribing aberration-controlling contact lenses for conditions such as keratoconus and PMD.
authors.affiliation: Department of Life Sciences, The University of Manchester, Manchester, United Kingdom.
authors.forename: Amit
authors.initials: A
authors.lastname: Jinabhai
authors.forename: Hema
authors.initials: H
authors.lastname: Radhakrishnan
authors.forename: Clare
authors.initials: C
authors.lastname: O'Donnell
mesh_terms: D000328:Adult; D003261:Contact Lenses; D003315:Cornea / Q000473:pathology*; D003316:Corneal Diseases / Q000150:complications* / Q000473:pathology* / Q000503:physiopathology; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000503:physiopathology / Q000534:rehabilitation; D004867:Equipment Design; D005260:Female; D005740:Gases / Q000493:pharmacokinetics; D006801:Humans; D007640:Keratoconus / Q000150:complications* / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D010539:Permeability; D012029:Refraction, Ocular; D014792:Visual Acuity
chemical_list: D005740:Gases