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Eric Brinton, Amitha Domalpally, Barbara Blodi; Reading Center Evaluation of Retinal Vein Occlusion Using Wide-field Angiography. Invest. Ophthalmol. Vis. Sci. 2013;54(15):5832.
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To develop a grading protocol to evaluate wide-field fluorescein angiography using the Optos grid in patients with retinal vein occlusions. The Optos widefield retinal imaging device is able to simultaneously image the far retinal periphery and the posterior pole. In addition, the expanded field detects peripheral retinal pathology that would otherwise not be seen on standard fluorescein angiography. This peripheral pathology may be significant in understanding the natural history and response to treatment of macular edema due to retinal vein occlusions. Studies to explore this link would require a standardized protocol to quantify areas of retinal pathology.
Using an Optos imaging device (OPTOS 200Tx SLO camera), fluorescein angiograms of branch and central retinal vein occlusions were taken on 8 patients (12 eyes) from one institution. The angiograms were analyzed using the wide-field grid used in color fundus photography and autofluorescence imaging in the Reykjavik Eye Study on macular degeneration. The wide-field grid was modified by consolidating three small central zones into one central zone in the macula. The mid-peripheral and peripheral zones were not modified. Optos grid placement was done in a standardized fashion using the disc and center of the macula as registration points. Two graders measured the percentage of leakage and non-perfusion in each of the 9 subfields. If < 50% of the subfield was visible due to artifact or dense blood, the subfield was marked as “cannot grade.”
Our results showed that 100% of the central and 97% of the mid-peripheral zones were gradable. Only 33% of the peripheral subfields were gradable, however. The inferior peripheral subfields were much less reliable due to prevalent lid and lash artifacts—only 1 out of 24 inferior subfields was gradable.
The Optos grid is a useful tool that can be used to reproducibly grade the central and mid-peripheral zones of the retina, although the peripheral zones can be difficult to grade. Our wide-field grading protocol uses a simple method of assessing leakage and non-perfusion by percent involvement of a subfield. This protocol allows for correlation of leakage and non-perfusion of the mid-peripheral and central retina. Change over time in percentage involvement of a subfield can also be assessed. These measurements may be of benefit in future trials of macular edema due to retinal vein occlusion.
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