Comparison of Three Handheld Fundus Cameras for Assessment of the Vertical Cup-To-Disk Ratio

ABSTRACT

Purpose To compare the quality of optic nerve photographs from three different handheld fundus cameras and to assess the reproducibility and agreement of vertical cup-to-disk ratio (VCDR) measurements from each camera. Methods Adult patients from a comprehensive ophthalmology clinic and an intravitreous injection clinic in northern Thailand were recruited for this cross-sectional study. Each participant had optic nerve photography performed with each of 3 handheld cameras: the Volk iNview, Volk Pictor Plus, and Peek Retina. Images were graded for VCDR in a masked fashion by two photo-graders and images with > 0.2 discrepancy in VCDR were assessed by a third photo-grader. Results A total of 355 eyes underwent imaging with three different handheld fundus cameras. Optic nerve images were judged ungradable in 130 (37%) eyes imaged with Peek Retina, compared to 36 (10%) and 55 (15%) eyes imaged with the iNview and Pictor Plus, respectively. For 193 eyes with gradable images from all 3 cameras, inter-rater reliability for VCDR measurements was poor or moderate for each of the cameras, with intraclass correlation coefficients ranging from 0.41 to 0.52. A VCDR ≥ 0.6 was found in 6 eyes on iNview images, 9 eyes on Pictor Plus images, and 3 eyes on Peek images, with poor agreement between cameras (e.g., no eyes graded as VCDR ≥ 0.6 on images from both the iNview and Pictor Plus). Conclusions Inter-rater reliability of VCDR grades from 3 handheld cameras was poor. Cameras did not agree on which eyes had large VCDRs.

KEYWORDS:

• Glaucoma
• photography
• diagnostic techniques
• ophthalmological
• reliability and validity

Acknowledgments

This work was supported by donations from the JaMel and Tom Perkins Family Foundation and the Fortisure Foundation to JDK and by donations from The All May See Foundation and Research to Prevent Blindness to the University of California San Francisco Department of Ophthalmology. LL was supported by an International Clinical Research Fellowship from the Fulbright U.S. Student Program and the Doris Duke Charitable Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the JaMel and Tom Perkins Family Foundation, Fulbright U.S. Student Program, Doris Duke Charitable Foundation, All May See Foundation, Fortisure Foundation, and Research to Prevent Blindness.