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Keratoconus diagnosis using Corvis ST measured biomechanical parameters
Roghiyeh Elham1,2, Ebrahim Jafarzadehpur3, Hassan Hashemi2
1Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran.
Journal of Current Ophthalmology
|September 16, 2017
Summary
The time of the first applanation (A1T) measured by Corvis ST technology effectively diagnoses keratoconus. This corneal biomechanical parameter shows excellent diagnostic ability, even when controlling for central corneal thickness.
Area of Science:
- Ophthalmology
- Biomechanical Engineering
- Medical Diagnostics
Background:
- Keratoconus is a progressive corneal ectasia affecting vision.
- Accurate diagnosis and staging are crucial for effective management.
- Corneal biomechanical properties offer potential diagnostic insights.
Purpose of the Study:
- To evaluate the diagnostic performance of corneal biomechanical parameters obtained via Scheimpflug imaging (Corvis ST) in identifying keratoconic corneas.
- To assess the ability of these parameters to differentiate between healthy and keratoconic eyes.
- To investigate the utility of these parameters for keratoconus staging.
Main Methods:
- Compared 10 biomechanical parameters from 48 keratoconic eyes and 50 normal eyes using Corvis ST.
- Analyzed parameters including applanation times (A1T, A2T), corneal displacement (HCT, HCDA), applanation lengths (A1L, A2L), velocities (A1V, A2V), peak distance (HCPD), and radius (HCR).
- Utilized receiver operating characteristic (ROC) curves to assess diagnostic power and performed analyses on CCT-matched subgroups.
Main Results:
- Eight of ten compared biomechanical parameters showed significant differences between keratoconic and normal eyes (P < 0.05).
- Applanation-1 time (A1T) and highest concavity radius (HCR) demonstrated excellent diagnostic ability (AUC > 0.9).
- A1T correctly identified over 93% of keratoconic eyes and maintained high diagnostic accuracy in CCT-matched subgroups.
Conclusions:
- Applanation-1 time (A1T) is a highly valuable and reliable parameter for diagnosing keratoconus.
- A1T exhibits excellent diagnostic power, independent of central corneal thickness.
- The evaluated biomechanical parameters were not found to be reliable indicators for staging keratoconus severity.
