Fundus Photography in the 21st Century--A Review of Recent Technological Advances and Their Implications for Worldwide Healthcare

Abstract

Background: The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly.

Literature review: Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera.

Results: Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer.

Conclusions: In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available.

Keywords: fundus camera; ophthalmic screening; portable camera system; portable eye examination kit; retinal photography; slit-lamp adaptors; smartphone-based camera system; tele-ophthalmology.

Fig. 1.

Flowchart depicting evolution and scope of retinal screening and fundus photography.

Fig. 2.

Illustrative representation of the miniature table-top fundus camera iCam. The table-top device images the retina by light-emitting diode illumination covering different parts of the retina through fixation targets. CCD, charge-coupled device.

Fig. 3.

Diagrammatic representation of fundus imaging by the digital retinography system (dRS). Equipped with wireless and Ethernet connectivity, this miniature table-top version also acquires fundus images through light-emitting diode illumination and fixation targets.

Fig. 4.

Modified hand-held fundus cameras using off-the-shelf point-and-shoot cameras. Additional optical components are assembled to transform a commercial digital camera into a fundus camera.

Fig. 5.

Integrated adaptor-detector-based hand-held ophthalmic cameras. The optical assembly is integrated with a display console, making it a user-friendly hand-held instrument. LCD, liquid crystal display.

Fig. 6.

Smartphone-based fundus camera system. An external ophthalmic lens is placed in front of the smartphone's lens for acquiring retinal images using the phone's built-in flash for illumination.

Fig. 7.

Adaptor-based fundus camera system. A smartphone is used as a display console for retinal images, and illumination and imaging optics are integrated to it externally.

Fig. 8.

The proposed complete cycle of tele-ophthalmology.