1New England College of Optometry, Boston, Massachusetts
2Wenzhou Medical University, Wenzhou, Zheniang, China
3Wang Vision, Boston, Massachusetts
∗[email protected]
Supplemental Digital Content: Video 1, available at https://links.lww.com/OPX/A470. This video demonstrates a new device that, when attached to a smartphone, is used for objective vision screening. It consists of a cylindrical main body, which holds the optical elements. On the top is the beam splitter. On the side is a handle to oscillate the beam side to side. This simulates the appearance of moving the entire instrument. The peephole creates a field of view for the camera lens of the smartphone. A nanosticker is used to adjust the alignment of the peephole and the camera lens as well as to hold the device firmly in place against the phone. The LED source, which provides the light for the retinal reflex, is inserted into the cylindrical container.
The following steps are used to prepare and use the device:
• Align the peephole of the device over the camera lens of the smartphone and press to attach it with the nanosticker.
• Turn on the video recording function of the camera. A round image formed by the peephole will be seen at the center of the video screen.
• Zoom the magnification of the camera to 5×.
• Turn on the light source, and from a distance of 1 m, project the beam onto the child’s forehead.
• Aim the vertical line in the middle of the beam onto the bridge of the nose just between the two eyes.
• Guide the child to look at a distant object.
• Slowly move the handle up and down and adjust the aim so that the beam enters both eyes symmetrically.
• As the beam crosses the child’s pupils, the retinal reflex will be seen on the screen and recorded.
• The speed and direction of the retinal reflex motion relative to the overall beam are indicative of the refractive status of the eye. The clarity of the ocular media can be assessed from viewing the retinal reflex.
• This child has approximately 1 D of myopia; therefore, the 1-m retinoscopic reflex is close to neutral. A series of lenses will be put in front of her left eye to simulate various refractive errors.
• With this lens, simulating 2 D of hyperopia, the reflex has obvious “with” motion.
• With this lens, simulating 1 D of hyperopia, there is a faster and brighter “with” motion and a wider reflex as neutrality is approached.
• With this lens, simulating 2 D of myopia, there is “against” motion of the retinoscopic reflex. As the device is moved closer to the eye, at about 50 cm, the reflex approaches neutrality, indicating 2 D of myopia.
• This girl is emmetropic. The 1-m retinoscopic reflex shows slight “with” motion.
• This boy has mild myopia with oblique astigmatism. Notice the “with” motion moving diagonally.
• With his astigmatic visual connection, the motion is that of an emmetrope.
Video 2, available at https://links.lww.com/OPX/A471. In this video of a young boy, the bright horizontal retinal reflex moves in the same direction as the retinoscopic beam, indicating the presence of moderate hyperopia. In this video of a young girl, the dim retinal reflex with the device at 1 m moves rapidly in the opposite direction from the motion of the beam of light. By moving the device closer to the eyes, the beam is brighter. Neutrality of the reflex motion occurs at 25 cm in the right eye and at 20 cm in the left eye, indicating 4 D of myopia and 5 D of myopia, respectively. This video shows how the smartphone attachment can be used to examine a newborn with very little effort, although it does require an assistant to hold the lids. In the right eye, a bright retinal reflex moves in the same direction as the retinoscopic beam, indicating hyperopia. Note the oblique motion of the retinal reflex in the left eye, indicating hyperopic astigmatism.
Submitted: October 7, 2019
Accepted: August 21, 2020
Funding/Support: None of the authors have reported funding/support.
Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest.
Study Registration Information: This article simply describes the prototype of an inexpensive device that can be used for visual screening in remote areas and storing the results for documentation or consultation. In-house testing has demonstrated its feasibility. Formal clinical validation studies are planned at Wenzhou Medical University to refine its final design, ensure its clinical precision, and test its scalability.
Author Contributions and Acknowledgments: Conceptualization: G-JW, JYW, CS, JQ, FL, DR, HP, JC; Data Curation: G-JW, JYW, CS; Formal Analysis: G-JW, JYW, CS; Investigation: G-JW, JYW, CS; Methodology: G-JW, JYW, CS; Resources: G-JW, JYW, CS; Validation: G-JW, JYW, CS; Visualization: G-JW, JYW, CS; Writing – Original Draft: G-JW, JYW, CS; Writing – Review & Editing: G-JW, JYW, CS.
The authors would like to acknowledge Hong Dongcun and Yuan Zhijian for their help with mechanical engineering.
Supplemental Digital Content: Direct URL links are provided within the text.
