@article{CroftHemert2014fk, abstract = {BACKGROUND AND OBJECTIVE: Accurate quantification of retinal surface area from ultra-widefield (UWF) images is challenging due to warping produced when the retina is projected onto a two-dimensional plane for analysis. By accounting for this, the authors sought to precisely montage and accurately quantify retinal surface area in square millimeters. PATIENTS AND METHODS: Montages were created using Optos 200Tx (Optos, Dunfermline, U.K.) images taken at different gaze angles. A transformation projected the images to their correct location on a three-dimensional model. Area was quantified with spherical trigonometry. Warping, precision, and accuracy were assessed. RESULTS: Uncorrected, posterior pixels represented up to 79\% greater surface area than peripheral pixels. Assessing precision, a standard region was quantified across 10 montages of the same eye (RSD: 0.7\%; mean: 408.97 mm(2); range: 405.34-413.87 mm(2)). Assessing accuracy, 50 patients' disc areas were quantified (mean: 2.21 mm(2); SE: 0.06 mm(2)), and the results fell within the normative range. CONCLUSION: By accounting for warping inherent in UWF images, precise montaging and accurate quantification of retinal surface area in square millimeters were achieved. [Ophthalmic Surg Lasers Imaging Retina. 2014;45:312-317.].}, author = {Croft, D.E. and van Hemert, J. and Wykoff, C.C. and Clifton, D. and Verhoek, M. and Fleming, A. and Brown, D.M.}, date-added = {2014-07-22 17:23:52 +0000}, date-modified = {2018-02-17 12:27:24 +0000}, doi = {10.3928/23258160-20140709-07}, issn = {2325-8179 (Electronic)}, journal = {Ophthalmic Surg Lasers Imaging Retina}, keywords = {retinal imaging; medical; image measurement}, month = {Jul}, number = {4}, pages = {312--317}, title = {Precise montaging and metric quantification of retinal surface area from ultra-widefield fundus photography and fluorescein angiography.}, volume = {45}, year = {2014}, bdsk-url-1 = {http://dx.doi.org/10.3928/23258160-20140709-07}}