Distinguishing between a nonischemic and an ischemic central retinal vein occlusion (CRVO) usually requires fluorescein angiography (FA). FA interpretation of the angiogram could be difficult since areas of hypofluorescence might represent ischemia or areas of blockage due to hemorrhage.1 Categorizing a CRVO as ischemic or nonischemic is helpful in establishing a prognosis for the patient. However, in pregnancy, it remains unclear whether FA can cause fetal harm.2 A non-risky alternative is to perform a 12 mm × 12 mm swept-source optical coherence tomography angiography (SS-OCTA) scan to assess the retinal perfusion for diagnosing and managing the patient.
A 32-year-old woman (gravida 2 para 1) at 31 weeks of gestation was referred to the Bascom Palmer Eye Institute because of vision loss in her left eye due to a CRVO. She had a history of amblyopia in the right eye. Best-corrected visual acuity (BCVA) was 20/25 in the right eye and 20/200 in the left eye, with no evidence of an afferent pupillary defect. Fundus examination of the right eye was unremarkable. The left eye revealed diffused superficial and deep intraretinal hemorrhages associated with tortuous vessels, cotton-wool spots along the arcades, and an edematous optic nerve (Figure 1A). To assess the extent of retinal ischemia, FA was avoided due to pregnancy, and a 12 mm x 12 mm SS-OCTA scan (PLEX Elite 9000; Carl Zeiss Meditec, Dublin, CA) was performed (Figure 2). The SS-OCTA instrument operated at 100-kHz with a central wavelength of 1,060 nm. The 12 mm × 12 mm total retinal en face flow image showed vascular tortuosity and no evidence of decreased perfusion (Figure 2A) with a retinal thickness map and accompanying B-scans that demonstrated extensive retinal and optic nerve edema (Figure 2B and 2C). She received an intravitreal injection of 4 mg triamcinolone acetonide (Triescence; Alcon Laboratories, Fort Worth, TX) in the left eye during that first visit. Her blood pressure, complete blood count, and coagulation profiles — which included protein S, protein C, antiphospholipid antibody, homocysteine, and factor V Leiden tests — were all within the normal ranges. Four weeks after the injection, her left eye BCVA improved to 20/25-2. Fundus image of the left eye showed resolving retinal hemorrhages (Figure 1B), and SS-OCTA images showed retinal perfusion and resolution of the retinal edema, optic nerve edema, and vascular tortuosity (Figures 2D, 2E, and 2F). Eight weeks after the injection, she delivered a healthy baby, and 5 months after the single intravitreal injection of steroid, her left eye BCVA was 20/20-2. The retina appeared normal by SS-OCTA imaging (Figure 2G, 2H, and 2I). Over the course of follow-up, the subfoveal choroidal thickness changed from about 400 μm at initial presentation to about 380 μm after 5 months.
Color fundus images of a central retinal vein occlusion in the left eye. (A) At initial presentation, the fundus images revealed diffused pre-retinal and intraretinal hemorrhages associated with tortuous vessels, cotton-wool spots along the arcades, and optic disc edema. (B) Four weeks after a single intravitreal injection of steroid at the first visit, the fundus image showed resolving retinal hemorrhages with a residual cotton-wool spot along the superior arcade.
12 mm × 12 mm swept-source optical coherence tomography angiography images and total retinal thickness maps of the left eye at baseline and at follow-up visits. (A–C) Baseline visit. (D–F) Four weeks after one intravitreal steroid injection. The residual cotton-wool spot along the superior arcade can been seen in the retinal en face flow image and in the thickness map. (G–I) Five months after the intravitreal injection. (A, D, G) Total retina en face flow image. (B, E, H) Total retinal thickness map. (C, F, I) B-scans through the fovea with dashed purple boundaries representing the boundaries for the en face images shown. Flow above the retinal pigment epithelium (RPE) is depicted in red and flow below the RPE is depicted as green.
To distinguish between a nonischemic and an ischemic CRVO, FA is usually performed, but in the presence of retinal hemorrhages, it may be difficult to determine if there are areas of retinal nonperfusion or whether the areas of hypofluorescence represent areas of blockage due to hemorrhage.1 According to the U.S. Food and Drug Administration, fluorescein sodium is classified as category C drug, which means that no adequate animal reproduction studies have been conducted, and it remains unclear whether fluorescein sodium can cause fetal harm when administered to a pregnant woman.2 Now with the availability of longer wavelength OCTA, SS-OCTA scans can assess the retinal perfusion in the macula even in the presence of retinal hemorrhages. The longer wavelength of 1,060 nm allows for better penetration through blood and into the choroid, and this instrument obtains wider field images compared with standard spectral-domain instruments.3 SS-OCTA imaging of our patient confirmed the typical changes found within the superficial and deep plexuses at initial presentation.4 From a single 12 mm × 12 mm SS-OCTA scan, both structure and flow images were acquired and if ischemic or nonperfused areas within the retina had been present, then they would have been detected. However, the scans did reveal the tortuous large hyperreflective retinal vessels on the en face OCT images.5 Combined with the ability to obtain multiple overlapping 12 mm × 12 mm images of the retina, it is possible to generate even wider field montaged images with a field of view of about 80°, and no evidence of decreased perfusion was identified. Although SS-OCTA is not able to view the far peripheral retina, it does allow the clinician to assess the retinal perfusion integrity of the posterior pole in eyes with a CRVO without risking any fetal harm that may arise from FA in pregnancy. For a CRVO, the use of 12 mm × 12 mm SS-OCTA imaging provides all the structural and flow information that is needed for assessing the diagnosis, prognosis, management, and response to therapy.
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- Hanhart J, Brosh K, Weill Y, Rozenman Y. Choroidal nevus-associated neovascular membrane demonstrated by OCT angiography. Case Rep Ophthalmol. 2017;8(1):104–107. doi:10.1159/000458516 [CrossRef]
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- Coscas F, Glacet-Bernard A, Miere A, et al. Optical coherence tomography angiography in retinal vein occlusion: Evaluation of superficial and deep capillary plexa. Am J Ophthalmol. 2016;161:160-171.e1–2. doi:10.1016/j.ajo.2015.10.008 [CrossRef]
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