To develop the Crow's Feet Grading Scale for objective quantification of the severity of lateral canthal lines and to establish the reliability of this photonumeric scale for clinical research and practice.
A 5-point photonumeric rating scale was developed to objectively quantify the severity of lateral canthal lines at rest and at maximum contracture of the orbicularis oculi. Nine experts rated photographs of 35 subjects, twice, with regard to the aspect crow's feet in comparison with morphed images. Inter- and intrarater variability was assessed by computing intraclass correlation coefficients.
The agreement between the experts was significantly high. Furthermore, the test–retest correlation coefficients were high for each expert after an overnight interval, demonstrating low inter- and intraevaluator variability.
The 5-point photonumeric scale generated spans the severity of the type of crow's feet for which patients most commonly seek correction. The scale is well stratified for consistent rating.
*Department of Dermatology and Skin Sciences, University of British Columbia, Vancouver, British Columbia, Canada; †Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada; ‡Research and Development, Merz Pharmaceuticals, Greensboro, North Carolina; §Department of Dermatology, University of California at Los Angeles, California; ¶Charité—Universitätsmedizin Berlin, Klinik für Dermatologie, Division of Evidence Based Medicine (dEBM), Berlin, Germany; ∥AboutSkin Dermatology and DermSurgery, Englewood, and Department of Dermatology, University of Colorado, Denver, Colorado; #Division of Cosmetic Sciences University of Hamburg, Germany; **Department of Dermatology, University of North Carolina at Chapel Hill, and Cary Skin Center, Cary, North Carolina; ††Division of Facial Plastic and Reconstructive Surgery, University of California at San Francisco, California; ‡‡Rosenparkklinik GmbH, Darmstadt, Germany; §§Canfield Scientific, Fairfield, NJ
Address correspondence and reprint requests to: Alastair Carruthers, MD, Suite 820-943 West Broadway, Vancouver, British Columbia, Canada V5Z 4E1, or e-mail: firstname.lastname@example.org
Drs. Alastair Carruthers, Jean Carruthers, Derek Jones, Berthold Rzany, Joel Cohen, Martina Kerscher, Timothy Corcoran Flynn, Corey Maas, and Gerhard Sattler are paid consultants to Merz Pharmaceuticals. Dr. Bhushan Hardas, Dr. Mandeep Kaur, Dr. Roman Goertelmeyer, Dr. Alexander Gebauer, Dr. Rainer Pooth, Kathleen McClure, and Ulli Simone-Korbel are employees of Merz Pharmaceuticals. Larry Buchner is an employee of Canfield Scientific.