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Longitudinal analysis of corneal topography in suspect keratoconus
  1. Mariko Shirayama-Suzuki,
  2. Shiro Amano,
  3. Norihiko Honda,
  4. Tomohiko Usui,
  5. Satoru Yamagami,
  6. Tetsuro Oshika (toshika{at}
  1. University of Tokyo, Japan
  2. University of Tokyo, Japan
  3. University of Tokyo, Japan
  4. University of Tokyo, Japan
  5. University of Tokyo, Japan
  6. University of Tsukuba, Clinical Medicine, Japan


    Aims: To examine the incidence of progression of keratoconus suspect to true keratoconus and compare quantitative descriptors of corneal topography between eyes with and without progression.

    Methods: We retrospectively reviewed 34 eyes with suspect keratoconus in 34 patients. Their age at the initial examination was from 13 to 40 years (24.1 ± 7.5, mean ± standard deviation), and the follow-up periods ranged from 3 to 10 years (6.0 ± 2.2 years). Keratoconus suspect was defined as the fellow eye of a clinically apparent keratoconus but that had no slit-lamp signs of keratoconus (Fleischer's ring, Vogt's striae, and Munson's sign) with best spectacle-corrected visual acuity of 20/20 or better. Eyes were monitored for the progression of apparent slit-lamp findings of keratoconus during the follow-up period. By using Fourier analysis of the corneal topography data, regular astigmatism, asymmetry component, and higher order irregularity component were calculated in the central 3-mm zone. Quantitative descriptors of corneal topography were compared between eyes which progressed to true keratoconus and those which did not.

    Results: Five eyes (14.7%) progressed to apparent keratoconus from keratoconus suspect (progression group), and 29 eyes did not (non-progression group). On average, it took 5.2 years for the eyes to develop apparent slit-lamp findings of keratoconus. Cumulative incidence of progression by Kaplan-Meier analysis was 21.5% in 6 years. Asymmetry component and regular astigmatism by Fourier analysis at the initial examination was significantly larger in the progression group than in the non-progression group.

    Conclusion: In our retrospective study, approximately 20% of eyes with suspect keratoconus progressed to true keratoconus in 6 years, and these eyes had presented greater asymmetry and regular astigmatism at the initial examination.

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