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Michelle Lima Farah, Murillo Santinello, Luis Eduardo Carvalho, Ronaldo Barcellos; A simple method to measure head tilt using iPhone®. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2933.
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© ARVO (1962-2015); The Authors (2016-present)
Abnormal head posture (AHP) is an important sign of several deseases. Some orthopedical such as scoliosis and congenital torticollis, others ophthalmic such as strabismus varieties, nistagmus, blepharoptosis, visual field and refractive defects. The purpose of the study was to describe a simple methodology for the measurement of abnormal head posture (AHP) using Smartphone app. This was an observational, cross-sectional study.
The app PHOTOS from iPhone® (Apple, Inc., Cupertino, CA) was used in this study, allowing rotation and adjustments of photographic records. Two strips were placed, a horizontal, on the wall behind the exam chair, at the patient’s head height and a sagittal (perpendicular to the wall) on the chair seat. The patients were photographed by IPhone® camera in two positions: frontal, with the head leaning over one shoulder (photo A1 with camera tilted and photo A2 without tilt), and upper axial, viewing forehead and nose turned to the right side (photo B1 with camera tilted and photo B2 without tilt). Another photograph was taken showing two lines, drawn on a card, forming a 32 angle, to prove the method’s precision. Thirty examiners were asked to edit the photographs in the app PHOTOS, according to previous explanation, in order to measure the head rotation related to the horizontal stripe (head tilted to the shoulder), to the sagittal stripe (right head turn) and the angle formed by the two lines on the card. Average of measurement and pattern deviation were calculated from all results obtained by the 30 examiners. The T-Student test was applied and the confidence interval (CI95%) was calculated.
All 30 examiners were able to measure the angles after explanation about the method. The examiners measurements of the card angle had a variation lower than 5%, proving the method’s precision to measure a known angle (p., The average measurements for photo A1 and A2 were 22.8 ± 2.77 and 21.4 ± 1.61, and for photo B1 and B2 were 19.6 ± 2.36 and 20.1 ± 2.33.
The measurement of AHP using iPhone® proved to be a simple and reproducible method. The maximum variation found were 2.88o regarding head tilt around the patient’s horizontal axis and 2.77o around the vertical axis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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