Quality and learning curve of handheld versus stand-alone non-mydriatic cameras

Abstract

Purpose: Nowadays, complex digital imaging systems allow detailed retinal imaging without dilating patients' pupils. These so-called non-mydriatic cameras have advantages in common circumstances (eg, for screening or emergency purposes) but present limitations in terms of image quality and field of view. We compare the usefulness of two non-mydriatic camera systems (ie, a handheld versus a stand-alone device) for fundus imaging. The primary outcome was image quality. The secondary outcomes were learning effects and quality grade-influencing factors.

Methods: The imaging procedures followed standard protocol and were all performed by the same investigator. Camera 1 (DRS^®) was a stand-alone system, while Camera 2 (Smartscope^® PRO) was a mobile system. In order to evaluate possible learning effects, we selected an examiner with no prior training in the use of these systems. The images were graded separately by two experienced and "blinded" ophthalmologists following a defined protocol.

Results: In total, 211 people were enrolled. Quality grade comparisons showed significantly better grades for Camera 1. Both systems achieved better quality grades for macular images than for disc-centered images. No remarkable learning effects could be demonstrated.

Conclusions: Both camera systems are useful for fundus imaging. The greater mobility of Camera 2 was associated with lower image quality. For screening scenarios or telemedicine, it must be determined whether image quality or mobility is more important.

Keywords: handheld camera; imaging; learning curve; non-mydriatic.

Figure 1

Image quality examples, beginning with grade 1 on the left side and ending with grade 5 on the right side. Note: The upper row is from Camera 1 and the lower row is from Camera 2.

Figure 2

Achieved quality grade (y-axis) for all images (upper panel) and sOD images (lower panel) divided into regions of interest, that is, macula versus disc (x-axis) and camera system (x-axis). Note: Box and whisker diagrams show 5% and 95% quantiles (whiskers) and 25% and 75% quantiles (box). Abbreviation: sOD, selection OD.

Figure 3

Achieved quality grade (y-axis) of images from the right eye of each patient (x-axis) divided into regions of interest, that is, macula versus disc (upper x-axis) and camera system (right y-axis). Note: The gray fields mark the 90% density ellipse.