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Maria Anna Mavrommatis, Nicole De Cuir, Juan Reynaud, C Gustavo De Moraes, Daiyan Xin, Robert Ritch, Brad Fortune, Donald Charles Hood; A method for measuring changes over time in paravascular defects. Invest. Ophthalmol. Vis. Sci. 2016;57(12):863.
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© ARVO (1962-2015); The Authors (2016-present)
To determine how paravascular defects (PDs) associated with epiretinal membranes (ERMs), high myopia, and glaucoma change over time using en-face slab optic coherence tomography (OCT) images.
13 glaucoma or glaucoma suspect eyes (10 patients) were selected from a larger group of 19 eyes with known PDs based on availability of wide-field (ss) OCT scans at two different time points (mean time between tests 1.5 yrs). All but 4 eyes had high myopia (≤-6D) (2 eyes), ERMs (4 eyes), and/or local arcuate defects (6 eyes), which are associated with PDs.[1,3] En-face images of slabs were generated from wide-field ssOCT cube scans (9x12 mm, 256 b-scans, 512 a-scans; DRI-OCT, Topcon, Inc) using special purpose software (ATL 3D-Suite).[1,2] PDs identified on en-face slab images were confirmed using horizontal b-scans and derived vertical b-scans, where they appeared as fissures and/or holes.[1,3] A b-scan perpendicular to the portion of the blood vessel with a PD was derived and the width of the defect was measured in order to quantify both the length and area of the defects (Fig.). The length and area of the PDs were calculated per blood vessel (BV) and per eye.
In these 13 eyes, PDs were identified at both time points along 1 to 5 BVs per eye for a total of 30 BVs. Although the average lengths of the PDs/BV and PDs/eye were about 8% longer at time 2 (Table), these changes were not statistically significant. Similarly, although the average areas of the individual PDs/BV and the PDs/eye were about 13% larger at time 2, these changes also were not statistically significant. Further, of the 30 PDs/BV, 15 increased in length and 15 decreased in length over time, while 18 (60%) increased in area over time while 12 (40%) decreased in area over time. However, the changes for one eye fell greater than 3 SD from the mean and showed clear increases in PD/BV length (1.97mm) and area (453.16mm2) and PD/eye length (2.58mm) and area (331.34mm2).
Although on average, the PDs did not show a significant increase in length or area over the relatively short period (mean 18 months) of this study, the PD in one eye clearly did. The method described here should prove useful for following eyes with PD over a longer time and for comparing these changes to progressive changes in glaucoma. 1. Hood, Fortune et al. IOVS, 2015 2.Fortune et al. IOVS, 2014 3. Muraoka et al. JAMA Ophthal, 2015
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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