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Pellucid marginal corneal degeneration: evaluation of the corneal surface and contact lens fitting
  1. C Gruenauer-Kloevekorn1,
  2. U Fischer2,
  3. K Kloevekorn-Norgall2,
  4. G I W Duncker1
  1. 1Department of Ophthalmology, Martin-Luther-University Halle, Germany
  2. 2Institute of Optometry Trothe-Optik, Halle, Germany
  1. Correspondence to: Dr Claudia Gruenauer-Kloevekorn Department of Ophthalmology, Martin-Luther-University, Ernst-Grube-Strasse 40, 06097 Halle, Germany; claudia.gruenauer-kloevekorn{at}medizin.uni-halle.de

Abstract

Aim: To quantify corneal irregularities, to describe the fitting with contact lenses, and to answer the question whether or not contact lenses with a special back surface design could improve visual acuity in patients with pellucid marginal corneal degeneration (PMCD).

Methods: 13 eyes were fitted with contact lenses with a special back surface. Videokeratographic data were assessed. The patients were followed up for an average period of 22.2 months. Lens tolerance and corrected visual acuity were evaluated.

Results: The mean eccentricity did not exceed 0.7 in all patients. Either the superior or the inferior eccentricity, or both, were negative in all patients. Using Fourier analysis all PMCD subjects showed an increased irregular astigmatism of the anterior cornea. Using Zernike coefficients seven eyes (53.8%) had a higher order aberration root mean square error (HOA RMS error) out of the normal range. The visual acuity with contact lenses improved in all eyes with an average increase of 2.7 lines (maximum eight lines). No serious complications were observed.

Conclusions: Quantitative evaluation of videokeratographic data may help to diagnose PMCD and to distinguish PMCD from other ectatic corneal diseases. Contact lenses with a special back surface design can improve visual acuity and lens tolerance.

  • BCVA, best corrected visual acuity
  • CL, contact lens
  • HOA, higher order aberration
  • PMCD, pellucid marginal corneal degeneration
  • RMS, root mean square
  • pellucid marginal corneal degeneration
  • rigid gas permeable contact lens
  • Fourier series harmonic analysis
  • Zernike coefficients
  • eccentricity
  • BCVA, best corrected visual acuity
  • CL, contact lens
  • HOA, higher order aberration
  • PMCD, pellucid marginal corneal degeneration
  • RMS, root mean square
  • pellucid marginal corneal degeneration
  • rigid gas permeable contact lens
  • Fourier series harmonic analysis
  • Zernike coefficients
  • eccentricity

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