Biomechanical and tomographic analysis of unilateral keratoconus

J Refract Surg. 2010 Sep;26(9):677-81. doi: 10.3928/1081597X-20091105-04. Epub 2009 Nov 16.

Abstract

Purpose: To evaluate and compare tomographic, clinical, and biomechanical data of patients with unilateral keratoconus and healthy controls.

Methods: Observational, case-control study. Complete clinical eye examination was followed by topographic (ATLAS), tomographic (Pentacam), and biomechanical (Ocular Response Analyzer) evaluation. Cases were sex- and age-matched with healthy individuals for controls.

Results: Four patients had unilateral keratoconus, and eight healthy patients served as controls. Central corneal thickness was 508±16 μm in the keratoconus group, 531±12.7 μm in the fellow eye group, and 528.6±40.7 μm in the control group (P>.125, all comparisons). Central keratometry was 43.70±2.70 diopters (D) in the keratoconus group, 42.84±1.43 D in the fellow eye group, and 43.81±1.94 D in the control group (P>.45, all comparisons). Corneal astigmatism was 3.30±2.24 D in the keratoconus group, 1.38±1.49 D in the fellow eye group, and 1.34±1.13 D in the control group (P=.037 between the keratoconus and control groups; P=.25 between the keratoconus and fellow eye groups). Corneal hysteresis was 8.13±2 mmHg in the keratoconus group, 8.96±0.86 mmHg in the fellow eye group, and 9.89±1.33 mmHg in the control group (P>.064, all comparisons). Corneal resistance factor was 7.96±2.43 mmHg in the keratoconus group, 8.92±1.39 mmHg in the fellow eye group, and 9.90±2.24 mmHg in the control group (P>.33, all comparisons).

Conclusions: Corneal hysteresis and corneal resistance factor values were not statistically different among the groups; however, a trend for lower values was found for keratoconus and fellow eyes compared to controls. Data should be interpreted with caution because of the small sample.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Biomechanical Phenomena / physiology*
  • Case-Control Studies
  • Cornea / physiopathology*
  • Corneal Topography
  • Female
  • Functional Laterality
  • Humans
  • Keratoconus / physiopathology*
  • Male
  • Middle Aged
  • Photography
  • Tomography
  • Young Adult