Related Experiment Video
Updated: Jul 28, 2026
Full-Field Optical Coherence Microscopy for Histology-Like Analysis of Stromal Features in Corneal Grafts
Published on: October 21, 2022
Optimized CorT Total to compare Scheimpflug vs dual Scheimpflug/Placido imaging devices.
Tanner J Ferguson1, Andre L Piccinini, Praneetha Thulasi
1From the Cole Eye Institute, Cleveland Clinic (Ferguson, Randleman), Cleveland, Ohio, USA; Sadalla Amin Ghanem Eye Hospital (Piccinini), Joinville, Brazil; Emory Eye Center, Emory University (Thulasi), Atlanta, Georia, USA; ASSORT Pty. Ltd. (Ong), NewVision Clinics (Stamatelatos, Alpins), and Department of Ophthalmology, University of Melbourne (Alpins), Melbourne, Australia.
The CorT Total method using Scheimpflug imaging better aligns with manifest refractive cylinder than manufacturer-provided total corneal power (TCP) measures. This optimized corneal topographic astigmatism calculation improves refractive outcomes.
Area of Science:
- Ophthalmology
- Optometry
- Corneal Imaging
Background:
- Accurate measurement of total corneal power (TCP) is crucial for refractive surgery planning.
- Existing methods for assessing corneal astigmatism have limitations in predicting refractive outcomes.
Purpose of the Study:
- To compare manufacturer-provided TCP measurements from Scheimpflug and dual Scheimpflug/Placido devices with an optimized corneal topographic astigmatism (CorT Total) calculation.
- To evaluate which method best correlates with manifest refractive cylinder.
Main Methods:
- A retrospective case series analyzed 209 eyes using Pentacam HR (Scheimpflug) and Galilei G4 (dual Scheimpflug/Placido) devices.
- Optimized CorT Total was computed from measured TCP data.
- Ocular residual astigmatism standard deviation (ORAsd) was used to compare measurement accuracy.
Main Results:
- The Scheimpflug CorT Total demonstrated the lowest ORAsd (0.306 D), indicating better agreement with manifest cylinder.
- This was statistically comparable to the dual Scheimpflug/Placido CorT Total (0.322 D).
- CorT Total from Scheimpflug imaging showed a statistically significant improvement over device-specific measures.
Conclusions:
- The CorT Total, particularly when generated with Scheimpflug imaging, provides a more accurate representation of corneal astigmatism relevant to refractive outcomes.
- This optimized calculation surpasses standard manufacturer-provided TCP measures from both imaging platforms.
