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Tarek A Shazly, Gabrielle R Bonhomme; Infrared-Augmented Digital Photography Technique For Pupillary Examination. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4114.
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Infrared photography is a useful tool for detection and documentation of pupillary size and reactivity. Infrared photographs and videos provide documentation and contribute to medical education of students and house-staff. However the dedicated equipment may not be widely available. Infrared cameras are sensitive only to infrared light by blocking visible light. Charge-coupled device (CCD) camera sensors are inherently sensitive to both visible and infrared light. Commercially available point and shoot cameras are typically equipped with infrared attenuating filters. These filters don’t completely block near infrared light in the 800nm-900nm range. Utilizing a regular digital camera for documentation of pupillary abnormalities becomes challenging under dim light conditions and in patients with dark colored irides. This problem can be solved by utilizing infrared illumination.
An unmodified 12 megapixel point and shoot digital camera was used to obtain binocular still photos and videos under different light conditions with near-infrared illumination. A commercially available infrared light emitting diode irradiating near-infrared light of 850 nm was used to illuminate the eyes, since this wavelength minimally stimulates pupillary light reaction while remaining visible to the camera. The infrared illumination allows the capture of clear pupil images in both dim and bright light conditions and allows easy visualization of the pupil despite pigmented irides, by increasing the contrast.
Photos and videos were obtained using the aforementioned technique demonstrating a variety of pupillary abnormalities, including afferent pupillary defects, light-near dissociation, and anisocoria due to Horner syndrome, tonic pupil, and third nerve palsy. This technique also allowed easy, rapid, and accurate measurement and documentation of the pupil sizes under dim and bright conditions.
This infrared-augmented photography technique supplements medical education, and aids in the more rapid detection, diagnosis and documentation of a wide spectrum of pupillary abnormalities. Its portability and ease of use with minimal training.
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