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V. V. Juthani, E. Farris; Use of Simultaneous Flicker Chronoscopy in the Detection of Glaucomatous Optic Nerve Progression and Its Association With Visual Field Progression. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3276.
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Simultaneous flicker chronoscopy is a technology where time series retinal photographs are converted into a movie and change is visible as motion. The purpose of this study is to determine if glaucomatous optic nerve progression as seen using simultaneous flicker chronoscopy is associated with visual field progression in patients with glaucoma, and to help elucidate the clinical utility of this mode of image analysis.
Optic nerve images of 300 separate eyes with photos from greater than one date were selected from a database of patients with glaucoma or suspicion of glaucoma. Optic nerve simultaneous flicker chronoscopy videos were created using a proprietary software (MatchedFlicker, EyeIC, Philadelphia, PA). These videos were first screened by one ophthalmology resident (VJ). The videos of the optic nerves that were thought to have progressed were then evaluated by a glaucoma specialist (EF). Those images showing progression by changes to the optic nerve structure, loss of rim tissue, displacement of optic nerve vessels or enlargement of beta atrophy were included. The Humphrey visual fields (HVFs) were then evaluated for progression by advancement of depth and degree of scotoma as analyzed by GHT analysis. Eyes that had progression of both the optic nerve and HVF were identified.
Simultaneous flicker videos of 300 different eyes were evaluated. 60 were initially thought to have progressed. Upon review by EF, 9 out of these 60, or 3% of total eyes screened were determined to have true progression using the above criteria. The average time to progression was 616.4 days. Among these 9, 2 eyes were seen to have progression on HVF (22.2%), 5 eyes were not seen to have progression (55.6%), and in the remaining 2 eyes, visual field deficits were too advanced to assess for progression (22.2%). False positives in the detection of optic nerve progression were most commonly due to image artifact, spontaneous venous pulsations, image misalignment, and differences in image brightness.
Simultaneous flicker chronoscopy is a new method of evaluating optic nerve progression in patients with glaucoma. In our series, only 2 of the 9 eyes showed immediate correlation between optic nerve progression and visual field progression. Further studies and temporal visual fields must be performed to determine if the changes seen on simultaneous matched flicker may predict future corresponding visual field deterioration.
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