Keratoconus Diagnosis and Progression Criteria Based on Multiple Imaging Devices
Narrative Responses:
Purpose
To evaluate keratoconus diagnosis and progression assessment based on modern anterior segment imaging modalities including Scheimpflug imaging, Placido Topography, Anterior-Segment Optical Coherence Tomography (AS-OCT), and novel Point-Source reflection Topography (PCT).
Methods
Two hundred fifty keratoconic cases were evaluated for keratoconic grading and anterior surface indexing by Scheimpflug imaging (Oculyzer , WaveLight AG), Placido Topography (Vario Topolyzer, WaveLight AG), AS-OCT (RTVue-100, Optovue Inc.) and a newly-introduced PCT (Cassini, i-Optics). The correlations between Scheimpflug- and Placido- derived keratoconic grading and anterior-surface irregularity indices for keratoconus were assessed with the AS-OCT and the PCT- derived keratoconus indices employing paired two-tailed t-tests, Bland-Altman plots, coefficient of determination (r2), and trend line linearity.
Results
Excellent agreement among the Scheimpflug- and Placido- derived keratoconic grading and anterior-surface irregularity indices for keratoconus with the AS-OCT and the PCT- derived keratoconus was observed.
Conclusion
The anterior-segment topographic indices may help aid in early diagnosis, proper monitoring and surgical follow-up in keratoconus by providing quantitative measure of ectasia progression. We present a benchmark for future studies for the development of keratoconus diagnosis, possibly providing an effective tool of postoperative crosslinking or other ectasia-management procedures monitoring.