Oren Golan1, Andre L Piccinini2, Eric S Hwang3, Ildamaris Montes De Oca Gonzalez4, Mark Krauthammer5, Sumitra S Khandelwal4, David Smadja6, J Bradley Randleman7. 1. Keck School of Medicine of the University of Southern California, Los Angeles, California, USA; Tel Aviv Souraski Medical Center, Tel Aviv University, Tel Aviv, Israel. 2. Keck School of Medicine of the University of Southern California, Los Angeles, California, USA; Sadalla Amin Ghanem Eye Hospital, Joinville, Santa Catarina, Brazil. 3. Keck School of Medicine of the University of Southern California, Los Angeles, California, USA. 4. Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. 5. Tel Aviv Souraski Medical Center, Tel Aviv University, Tel Aviv, Israel. 6. Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel. 7. Keck School of Medicine of the University of Southern California, Los Angeles, California, USA; USC Roski Eye Institute, Los Angeles, California, USA. Electronic address: randlema@usc.edu.
Abstract
PURPOSE: To identify the best metrics or combination of metrics that provide the highest predictive power between normal eyes and the clinically unaffected eye of patients with highly asymmetric keratoconus using data from a Dual Scheimpflug/Placido device. DESIGN: Retrospective case-control study. METHODS: Combined Dual Scheimpflug/Placido imaging was obtained from the Galilei G4 device (Ziemer Ophthalmic Systems AG, Port, Switzerland) in 31 clinically unaffected eyes with highly asymmetric keratoconus and 178 eyes from 178 patients with bilaterally normal corneal examinations that underwent uneventful LASIK with at least 1 year follow-up. Receiver operating characteristic (ROC) curves were generated to determine area under the curve (AUC), sensitivity, and specificity for 87 metrics, and logistic regression modeling was used to determine optimal variable combinations. RESULTS: No individual metric achieved an AUC greater than 0.79. A combined model consisting of 9 metrics yielded an AUC of 0.96, with 90.3% sensitivity and 92.6% specificity. Among those 9 metrics included, 5 related to corneal pachymetry: Opposite Sector Index and Anterior Height BFS Z from the anterior surface, Asphericity and Asymmetry Index, Posterior Height BFS Z, and Posterior Height BFS X from the posterior surface. The strongest variable in the model was the thinnest point location on the horizontal (x) axis. CONCLUSION: While individual metrics performed poorly, using a combination of metrics from the combined Dual Scheimpflug/Placido device provided a useful model for differentiating normal corneas from the clinically normal eyes of patients with highly asymmetric keratoconus. Pachymetry values were the most impactful metrics.
PURPOSE: To identify the best metrics or combination of metrics that provide the highest predictive power between normal eyes and the clinically unaffected eye of patients with highly asymmetric keratoconus using data from a Dual Scheimpflug/Placido device. DESIGN: Retrospective case-control study. METHODS: Combined Dual Scheimpflug/Placido imaging was obtained from the Galilei G4 device (Ziemer Ophthalmic Systems AG, Port, Switzerland) in 31 clinically unaffected eyes with highly asymmetric keratoconus and 178 eyes from 178 patients with bilaterally normal corneal examinations that underwent uneventful LASIK with at least 1 year follow-up. Receiver operating characteristic (ROC) curves were generated to determine area under the curve (AUC), sensitivity, and specificity for 87 metrics, and logistic regression modeling was used to determine optimal variable combinations. RESULTS: No individual metric achieved an AUC greater than 0.79. A combined model consisting of 9 metrics yielded an AUC of 0.96, with 90.3% sensitivity and 92.6% specificity. Among those 9 metrics included, 5 related to corneal pachymetry: Opposite Sector Index and Anterior Height BFS Z from the anterior surface, Asphericity and Asymmetry Index, Posterior Height BFS Z, and Posterior Height BFS X from the posterior surface. The strongest variable in the model was the thinnest point location on the horizontal (x) axis. CONCLUSION: While individual metrics performed poorly, using a combination of metrics from the combined Dual Scheimpflug/Placido device provided a useful model for differentiating normal corneas from the clinically normal eyes of patients with highly asymmetric keratoconus. Pachymetry values were the most impactful metrics.
Authors: Majid Moshirfar; Mahsaw N Motlagh; Michael S Murri; Hamed Momeni-Moghaddam; Yasmyne C Ronquillo; Phillip C Hoopes Journal: Med Hypothesis Discov Innov Ophthalmol Date: 2019
Authors: Louise Pellegrino Gomes Esporcatte; Marcella Q Salomão; Bernardo T Lopes; Paolo Vinciguerra; Riccardo Vinciguerra; Cynthia Roberts; Ahmed Elsheikh; Daniel G Dawson; Renato Ambrósio Journal: Eye Vis (Lond) Date: 2020-02-05