April 2011
Volume 52, Issue 14
Free
ARVO Annual Meeting Abstract  |   April 2011
Evaluation of the Diagnostic Performance of the Ocular Response Analyzer for Subclinical Keratoconus
Author Affiliations & Notes
  • Fernando Fuentes Bonthoux
    Ophthalmology, Hospital de Clinicas, University of Buenos Aires, Buenos Aires, Argentina
    Special Studies Section, Pförtner Laboratory, Buenos Aires, Argentina
  • Jeremias Galletti
    Ophthalmology, Hospital de Clinicas, University of Buenos Aires, Buenos Aires, Argentina
    Special Studies Section, Pförtner Laboratory, Buenos Aires, Argentina
  • Tomas Pförtner
    Special Studies Section, Pförtner Laboratory, Buenos Aires, Argentina
  • Footnotes
    Commercial Relationships  Fernando Fuentes Bonthoux, None; Jeremias Galletti, None; Tomas Pförtner, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science April 2011, Vol.52, 5172. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Fernando Fuentes Bonthoux, Jeremias Galletti, Tomas Pförtner; Evaluation of the Diagnostic Performance of the Ocular Response Analyzer for Subclinical Keratoconus. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5172.

      Download citation file:


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

      ×
  • Supplements
Abstract
 
Purpose:
 

To evaluate the performance of previously derived diagnostic cutoff points for corneal hysteresis (CH) and corneal resistance factor (CRF) for detecting subclinical keratoconus.

 
Methods:
 

65 eyes from 65 healthy subjects in group 1 and 67 eyes from 67 keratoconus patients were evaluated with Ocular Response Analyzer (ORA), corneal topography, aberrometry and anterior segment optical coherence tomography. Only eyes with central corneal thickness (CCT) between 441 and 560 µm were included, and for group 2, the eye with the lowest average corneal power (ACP) was chosen. Observations were stratified in 20-µm intervals to which cutoff points obtained from previous work on an independent sample were applied. The Keratoconus Severity Score (KSS) was used to grade keratoconus.

 
Results:
 

Group 2 eyes had lower CCT (µm, 515.1±3.516 vs 492.0±3.386, p<0.01), CH (9.417±0.1951 vs 8.427±0.1702, p<0.01) and CRF (9.095±0.2161 vs 7.382±0.1985, p<0.01). CH and CRF cutoff points had overall 79.1% and 82.1% sensitivity and 50.8% and 60.0% specificity, respectively, for detecting keratoconus. 49 eyes (73.1%) in group 2 did not meet topographic criteria for keratoconus (KSS≤2), but fellow eyes of these observations had manifest keratoconus (KSS≥2). CH and CRF sensitivity for these subclinical keratoconus eyes was 85.7% and 81.6%, respectively. False positive cases for both parameters had significantly more negative refractive spherical equivalent (for CRF, -6.619±0.9553 vs -10.03±1.185, p=0.03), but did not differ meaningfully in ACP or higher-order aberrations of the first corneal surface.

 
Conclusions:
 

CH and CRF can detect subclinical biomechanical abnormalities if the confounding effect of CCT on these measurements is considered. Overall diagnostic performance seems to be better for CRF and the false positive rate could be partially ascribed to highly myopic eyes, which also show weakened corneal biomechanics. ORA could constitute a useful adjunct in the preoperative evaluation of refractive surgery candidates.  

 
Keywords: keratoconus • detection • refractive surgery: other technologies 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×