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Kaspar Schürch, Stephen H Tsang, Winston Lee, Katherine Boudreault, Tobias Duncker, Russell L Woods, Francois C Delori, Janet R Sparrow; Quantifying Fundus Autofluorescence Rings in Patients with Retinitis Pigmentosa. Invest. Ophthalmol. Vis. Sci. 2016;57(12):148. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Quantitative fundus autofluorescence (qAF) enables measurement of fundus AF intensities amongst groups of individuals. We applied the qAF approach to study the high autofluorescent rings that are often a feature of fundus autofluorescence (AF) images obtained from patients with retinitis pigmentosa (RP).
Ten (10) RP patients (age 15 to 56 years; total 17 eyes) having clearly defined autofluorescent rings, clear lenses and no floaters were selected for study. Inheritance was autosomal dominant in 3 patients and autosomal recessive in the others. AF images (30°, 488 nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. After exclusion of the vessels, gray level intensities in rectangular regions of interest (ROI) (2395 ± 930 pixels) over and outside the ring were obtained in the superior, temporal and inferior aspect of each ring. qAF-units were calculated. Control values consisted of previously published data from age-similar healthy subjects with no family history of retinal dystrophy. qAF values are reported relative to the 95% confidence interval (CI) for the same retinal location in age-matched healthy eyes.
qAF values outside and over the rings could be higher, similar or lower than qAF values at the same position in age-similar healthy eyes. Seven (7) eyes were found to have higher qAF-units in all 3 quadrants over of the ring compared to qAF values at the same location in healthy age-matched eyes. Additionally, in 2, 1 and 0 eyes qAF was only higher temporally, inferiorly and superiorly, respectively. Thus in 24/51 eyes (47%) qAF in the ROI over the ring was higher than in healthy eyes. One eye had qAF-units below the 95%CI outside the ring, with values over the ring being within the normal range in all 3 quadrants.
Although the qAF values associated with AF rings in the RP patients varied, in 47% of cases, qAF over the ring was outside the 95% CI for age-matched healthy eyes. The high qAF indicates that increased fluorophore production may be a factor in the formation of the rings.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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