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R Joel Welch, Jonathan Crews, Quan Dong Nguyen; Inexpensive model for learning the technique and principles of wide-angle smartphone ophthalmic photography. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1688.
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© 2017 Association for Research in Vision and Ophthalmology.
Smartphone ophthalmic photography has grown in popularity over recent years; nevertheless, many eyecare professionals struggle to capture smartphone fundus images. This proof-of-concept study demonstrates how an inexpensive eye model can help healthcare professionals master the technique of smartphone retinal imaging before taking images of live patients.
An eye model was made by printing five 25 mm square images on white cardstock paper. The paper was folded into a 25 x 25 x 25 mm cube with images appearing on its inside surfaces. One surface was left blank through which a 7 mm-round opening was made to simulate a mydriatic pupil. Next, an iPhone 6s (Apple Inc., Cupertino, CA, USA) and 20D/28D lenses (Volk Optical Inc., Mentor, OH, USA) were used to capture images of the inside of the model. During image capture, single measurements of the distances between phone, lens, and model were taken. Similar measurements were made during Smartphone fundus photography of a human retina and these distances were compared. Adobe Photoshop (Adobe Systems Inc, San Jose, CA, USA) was used to crop individual images and create montages.
When using the model, best image focus was achieved while holding the 28D lens 4.1 cm from the surface of the model and holding the smartphone 31.3 cm from the condensing lens (Figure 1). For the 20D lens, these distances were 6.0 cm and 36.3 cm, respectively. When photographing a human retina, best image focus was achieved by positioning the 28D lens 4.3 cm from the ocular surface and holding the smartphone 31.0 cm from the condensing lens. For the 20D lens, these distances were 6.2 cm and 36.0 cm, respectively, (Figure 2).
This inexpensive model simulates the technique required for smartphone ophthalmic photography of the human retina. It will help healthcare professionals master the technique of smartphone retinal imaging and liberate patients from the unnecessary consequences (e.g., time, light exposure) of the learning curve associated with the technique. Furthermore, this study demonstrates an attachment-free technique for acquiring wide-angle smartphone fundus photographs thus negating the need to purchase costly smartphone accessories.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Figure 1. Model template, A. Assembled model cube with 7 mm aperture, B. Montage of smartphone images using 28 D lens, C.
Figure 2. Montage image of human retina using smartphone and 20 D lens.
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