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In Reply We thank Choi and Yoon for bringing to our attention their recent article titled “Margin Reflex Distance: Differences Based on Camera and Flash Positions.”1 Their results regarding the error introduced into photometric measurements of margin reflex distance 1 caused by displacement of the flash from the optical axis of the camera indeed correlate extremely well with our own.2 Importantly, they confirm our findings that the error can be minimized by orienting the flash such that it is in the same horizontal plane as the optical axis of the camera, or by minimizing the angle between the flash and the camera lens. Additionally, the use of a ring flash, which we did not explore in our own study, can effectively neutralize the flash displacement artifact.
Bodnar ZM. Validation of Software Measurements of Eyelid Position From Digital Photographs—Reply. JAMA Ophthalmol. 2016;134(5):607. doi:10.1001/jamaophthalmol.2016.0220