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MINAMI ISHII, Tomoka Ishida, Kei Morohoshi, Kyoko Ohno-Matsui; Detection of Zinn-Haller arterial ring in highly myopic eyes by optical coherence tomography angiography. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5750.
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© ARVO (1962-2015); The Authors (2016-present)
The peripapillary arterial circle of Zinn-Haller (ZHAC) is a main feeding vessel of of the optic nerve at the level of the lamina cribrosa, which is the major insult site of optic nerve damage in eyes with glaucoma. We performed an observational clinical study to delineate the ZHAC by non-invasive optical coherence tomography angiography (OCT-A).
306 eyes of 153 consecutive patients with pathologic myopia were examined using OCT-A (RTVue XR Avanti) and whose ZHAC was carefully obsereved by OCT-A and compared to the images of color fundus photo and indocyanine green angiography (ICGA). The location of ZHAC was classified into nasal, upper, temporal (upper-temporal and lower-temporal) and lower. The definition of pathologic myopia was a refractive error (spherical equivalent) <-8.00 diopters (D) or an axial length >26.5 mm.
The ZHAC was visible within the area of myopic conus in 26 of 282 highly myopic eyes (9.2%) by OCT-A. The location of ZHAC was identified in the temporal area in 12 eyes (46.2%), temporal to lower area in 10 eyes (38.5%), upper area to temporal to lower area in 3 eyes (11.5%), nasal and upper area to temporal to lower area in 1 eye (3.8%), respectively. The shape of ZHAC was circular in 18 eyes (69.2%), rhomboid in 4 eyes (15.4%), irregular in 2 eyes (7.7%) and “circular and rhomboid” in one eye (3.5%), respectively. The proportion of the ZHAC shapes detected by ICGA was perfectly the same as the results from OCT-A. OCT-A provided high-resolution images of smaller branch blood vessels from ZHAC comparable to or even better than ICGA.
This study suggested that OCT-A technique can be an alternative method to ICGA to examine the Zinn-Haller ring in eyes with high myopia. Further study of ZHAC with OCT-A may improve understanding of glaucoma and myopic optic neuropathy causing optic nerve atrophy.
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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