Advances in automated alternation flicker

May 01, 2014

The authors have sought to expand the concept of automated alternation flicker to improve detection of glaucomatous optic neuropathy and highlight their findings in this article.

The opportunity to intervene in the disease's natural course by early detection and regular monitoring for progression has motivated a long history of efforts to improve the identification of glaucomatous structural changes. In most ophthalmic practices today, glaucoma is diagnosed and monitored with optic nerve photography and scanning ophthalmic laser imaging. Side-by-side review of optic nerve photographs is the current standard and most commonly applied technique for image review, yet its limitations include inconsistent interpretations leading to low interobserver reliability and a high rate of false positives.1

Alternation flicker

Automated alternation flicker (AAF) has made flicker's application more practical by using an algorithm that automatically aligns and alternates optic nerve photos on any digital display. Thus, flicker can be readily viewed during a patient examination and potentially inform clinical management. AAF has been validated to provide a sensitive method for detecting features of glaucomatous structural progression.

Researcher Dr Brian L. VanderBeek published the high sensitivity of AAF for detecting peripapillary atrophy in Glaucoma, while also noting its advantages over traditional image review strategies.2

"Alternation flicker demonstrated greater agreement and repeatability than side-by-side photographic comparison, the current clinical standard," commented Dr VanderBeek.

AAF has also been shown to be effective in identifying risk factors for functional progression. A study by Dr Ru-Ik Chee and other researchers evaluating the agreement between flicker chronoscopy for structural glaucomatous progression and factors associated with progression found support for flicker's validity.

"Reproducing the established association between age and progression supports the notion that flicker may be a valid tool to judge structural progression. Using flicker, an efficient and clinic-ready tool, we have also reproduced [the association between older age and peripapillary atrophy], further supporting the validity of flicker chronoscopy," wrote Dr Chee in the American Journal of Ophthalmology.3

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