Advanced Corneal Imaging in Keratoconus

A Report by the American Academy of Ophthalmology Ophthalmic Technology Assessment Committee Cornea and Anterior Segment Disorders Panel

Anthony N. Kuo, MD;¹ Maria S. Cortina, MD;² Mark A. Greiner, MD,³ Jennifer Y. Li, MD;⁴ Darby D. Miller, MD, MPH;⁵ Roni M. Shtein, MD, MS;⁶ Peter B. Veldman, MD;⁷Jia Yin, MD, PhD, MPH;⁸ Stephen J. Kim, MD;⁹ Joanne F. Shen, MD¹⁰

Ophthalmology, Vol. 131, Issue 1, P107-121 © 2023 by the American Academy of Ophthalmology. Click here for free access to the OTA.

Purpose: To review the published literature on the diagnostic capabilities of the newest generation of corneal imaging devices for the identification of keratoconus.

Methods: Corneal imaging devices studied included tomographic platforms (Scheimpflug photography, OCT) and functional biomechanical devices (imaging an air impulse on the cornea). A literature search in the PubMed database for English language studies was last conducted in February 2023. The search yielded 469 citations, which were reviewed in abstract form. Of these, 147 were relevant to the assessment objectives and underwent full-text review. Forty-five articles met the criteria for inclusion and were assigned a level of evidence rating by the panel methodologist. Twenty-six articles were rated level II, and 19 articles were rated level III. There were no level I evidence studies of corneal imaging for the diagnosis of keratoconus found in the literature. To provide a common cross-study outcome measure, diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were extracted. (A perfect diagnostic test that identifies all cases properly has an AUC of 1.0.)

Results: For the detection of keratoconus, sensitivities for all devices and parameters (e.g., anterior or posterior corneal curvature, corneal thickness) ranged from 65% to 100%. The majority of studies and parameters had sensitivities greater than 90%. The AUCs ranged from 0.82 to 1.00, with the majority greater than 0.90. Combined indices that integrated multiple parameters had an AUC in the mid-0.90 range. Keratoconus suspect detection performance was lower with AUCs ranging from 0.66 to 0.99, but most devices and parameters had sensitivities less than 90%.

Conclusions: Modern corneal imaging devices provide improved characterization of the cornea and are accurate in detecting keratoconus with high AUCs ranging from 0.82 to 1.00. The detection of keratoconus suspects is less accurate with AUCs ranging from 0.66 to 0.99. Parameters based on single anatomic locations had a wide range of AUCs. Studies with combined indices using more data and parameters consistently reported high AUCs.

¹Duke Eye Center, Duke University Medical Center, Durham, North Carolina
²Associate Professor of Ophthalmology, Department of Ophthalmology and Visual Science, University of Illinois College of Medicine, Chicago, Illinois 
³Department of Ophthalmology and Visual Sciences, Carver College of Medicine and Institute for Vision Research, University of Iowa, Iowa City, Iowa 
⁴UC Davis Eye Center, University of California, Davis, California 
⁵Department of Ophthalmology, Mayo Clinic, Jacksonville, Florida 
⁶Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan 
⁷Department of Ophthalmology & Visual Sciences, The University of Chicago, Chicago, Illinois 
⁸Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 
⁹Department of Ophthalmology, Vanderbilt University School of Medicine, Nashville, Tennessee 
¹⁰Department of Ophthalmology, Mayo Clinic, Scottsdale, Arizona