April 2014
Volume 55, Issue 13
ARVO Annual Meeting Abstract  |   April 2014
Analysis of Predictors of Keratoconus Progression
Author Affiliations & Notes
  • Naoko Kato
    Ophthalmology, National Defense Medical College, Tokorozawa, Japan
    Ophthalmology, Keio University School of Medicine, Tokyo, Japan
  • Kazuno Negishi
    Ophthalmology, Keio University School of Medicine, Tokyo, Japan
  • Megumi Saiki
    Ophthalmology, Keio University School of Medicine, Tokyo, Japan
  • Kazuo Tsubota
    Ophthalmology, Keio University School of Medicine, Tokyo, Japan
  • Footnotes
    Commercial Relationships Naoko Kato, None; Kazuno Negishi, None; Megumi Saiki, None; Kazuo Tsubota, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 4208. doi:
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      Naoko Kato, Kazuno Negishi, Megumi Saiki, Kazuo Tsubota; Analysis of Predictors of Keratoconus Progression. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4208.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose: Keratoconus is a congenital, progressive, ecstatic disease of the cornea. However, the mechanism of exacerbation is unclear. We retrospectively analyzed the characteristics of keratoconus patients to identify predictors of disease progression.

Methods: This study retrospectively analyzed 55 eyes of 35 patients (10 females and 25 males; age, 25.3±8.0 years) with keratoconus, who were followed for at least 6 months at our institute. In addition to standard ophthalmic examinations, we investigated the change in manifest refraction (spherical equivalents [SE] and cylinder power [Cyl]), steepest keratometric value (Ks), and thinnest corneal thickness (TCT). We also asked the age at which the patients were diagnosed with keratoconus. We defined progression as a decrease of more than 0.5 diopters per year (D/Y) for SE and increases of 0.5 D/Y for Cyl and Ks. We assigned progression scores from 0 to 3 as follows: 0, no progression observed for SE, Cyl, and Ks; 1, one of the factors progressed; 2, two factors progressed; and 3, all three factors progressed.

Results: The age at diagnosis ranged from 14 to 41 years. At the first visit, SE, Cyl, Ks, and TCT were -4.41±4.24 D, -3.05±2.01 D, 50.42±7.25 D, and 451.7 ± 62.1 µm, respectively. SE progressed - 0.95 ± 5.93 D/Y, Cyl increased 0.44 ± 3.07 D/Y, the steepest K-value increased 0.44 ± 3.07 D/Y, and the TCT decreased 4.45 ± 18.08 µm per year. Spearman’s rank correlation test showed that the rates of change of SE, Cyl, and the progression score were correlated with the change in TCT (ρ = 0.3375, 0.3816, and -0.331; p = 0.0165, -0.0063, and 0.0189, respectively). Ks was correlated with the rate of change of Cyl (ρ = 0.3012, p = 0.0269). The rate of change of Ks was correlated with patient age at the first visit (ρ = -0.2845, p = 0.039).

Conclusions: A thin, steep cornea may help to predict the progression of keratoconus. Particularly, the decrease in corneal thickness is an important indicator of progression; however, patient age could be a secondary factor.

Keywords: 574 keratoconus • 464 clinical (human) or epidemiologic studies: risk factor assessment • 479 cornea: clinical science  

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