Predictors of Photographic Quality with a Handheld Nonmydriatic Fundus Camera Used for Screening of Vision-Threatening Diabetic Retinopathy

Abstract

Purpose: To analyze predictors of image quality for a handheld nonmydriatic fundus camera used for screening of vision-threatening diabetic retinopathy.

Methods: An ophthalmic photographer at an Aravind Eye Hospital obtained nonmydriatic and mydriatic fundus images from 3 fields in 275 eyes of 155 participants over 13 months using a Smartscope camera (Optomed, Oulu, Finland) and a Topcon tabletop fundus camera (Topcon, Tokyo, Japan). Two fellowship-trained retina specialists graded the images. Repeated-measures logistic regression assessed predictors of the main outcome measure: gradability of the fundus images.

Results: Of 2,475 images, 76.2% of the Smartscope nonmydriatic images, 90.1% of the Smartscope mydriatic images, and 92.0% of the Topcon mydriatic images were gradable. Eyes with vitreous hemorrhage (OR = 0.24, p < 0.0001) or advanced cataract (OR = 0.08, p < 0.0001) had decreased odds of image gradability. Excluding eyes with cataract or vitreous hemorrhage, nonmydriatic macular image gradability improved from 68.4% in the first set of 55 eyes to 94.6% in the final set of 55 eyes.

Conclusion: With sufficient training, paraprofessional health care staff can obtain high-quality images with a portable nonmydriatic fundus camera, particularly in patients with clear lenses and clear ocular media.

Keywords: Diabetic retinopathy; Image quality; Screening; Telemedicine.