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Clinical Trial
. 2017 Jan;11(1):128-134.
doi: 10.1177/1932296816658902. Epub 2016 Jul 11.

Screening for Diabetic Retinopathy Using a Portable, Noncontact, Nonmydriatic Handheld Retinal Camera

Wenlan Zhang  1 , Peter Nicholas  1 , Stefanie Gail Schuman  1 , Michael John Allingham  1 , Ambar Faridi  1 , Tushar Suthar  1 , Scott William Cousins  1 , Sasapin Grace Prakalapakorn  1
Affiliations
Clinical Trial

Screening for Diabetic Retinopathy Using a Portable, Noncontact, Nonmydriatic Handheld Retinal Camera

Wenlan Zhang et al. J Diabetes Sci Technol. 2017 Jan.

Abstract

Background: Diabetic retinopathy (DR) is a leading cause of low vision and blindness. We evaluated the feasibility of using a handheld, noncontact digital retinal camera, Pictor, to obtain retinal images in dilated and undilated eyes for DR screening. We also evaluated the accuracy of ophthalmologists with different levels of training/experience in grading these images to identify eyes with vision-threatening DR.

Methods: A prospective study of diabetic adults scheduled to have dilated eye exams at Duke Eye Center from January to May 2014 was conducted. An imager acquired retinal images pre- and postdilation with Pictor and selected 1 pre- and 1 postdilation image per eye. Five masked ophthalmologists graded images for gradability (based on image focus and centration) and the presence of no, mild, moderate, or severe nonproliferative DR (NPDR) or proliferative DR (PDR). Referable disease was defined as moderate or severe NPDR or PDR on image grading. We evaluated feasibility based on the graders' evaluation of image gradability. We evaluated accuracy of identifying vision-threatening disease (severe NPDR or PDR documented on dilated clinical examination) based on the graders' sensitivity and specificity of grading referable disease.

Results: Images were gradable in 86-94% of predilation and 94-97% of postdilation photos. Compared to the dilated clinical exam, overall sensitivity for identifying vision-threatening DR was 64-88% and specificity was 71-90%.

Conclusions: Pictor can capture retinal images of sufficient quality to screen for DR with and without dilation. Single retinal images obtained using Pictor can identify eyes with vision-threatening DR with high sensitivity and acceptable specificity compared to clinical exam.

Keywords: diabetic retinopathy; handheld camera; portable imaging; retina; screening; telemedicine.

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Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The authors have completed the ICMJE Form for Disclosure of Potential Conflicts of Interest. For disclosures reported by SGP, PN, and SWC, the funding organization had no role in the design or conduct of the study; collection, management, analysis, or interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication. There are no other disclosures to report.

Figures

Figure 1.
Figure 1.
Images of the Pictor camera in the photographer’s hand (side view) (a) and from the photographer’s perspective (live-view monitor) (b) and example of a slide set composed of the color (c) and corresponding red-free (d) retinal images of a left eye taken with the Pictor camera showing good focus, centration of the macula, and the optic nerve and temporal vascular arcades in view.
Figure 2.
Figure 2.
Demographics of study population and information of acquired Pictor images.
See this image and copyright information in PMC

References

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