This patient had a central retinal vein occlusion CRVO with substantial progression during the two weeks after her initial presentation to our practice. Such a clinical course is not rare for a CRVO. Initially, there was mild venous tortuosity in all quadrants in the left eye relative to the right eye, and this tortuosity increased between the two visits. The number of cotton wool spots is unusual for CRVOs, and they suggested arterial occlusive disease. However, the fluorescein angiogram did not show significant delay of arterial or venous filling. There was nonperfusion in the posterior pole, which correlated with the many cotton-wool spots. There was disc leakage and leakage from blood vessels due to general retinal ischemia.
CRVOs in otherwise healthy patients under 50 years of age are unusual, and laboratory testing for a hypercoagulable state was indicated. The testing was remarkable for an elevated homocysteine of 20.4 (normal 0-14.5) with normal B6 and folate levels. The CBC was unremarkable, and the angiotensin converting enzyme and lysozyme levels were normal. The patient had a negative Factor V Leiden and an unremarkable immunoelectrophoresis. Treatment of hyperhomocysteinemia is with a combination of vitamin B6 (pyridoxine), folate, and betaine.
An interesting feature of this patient’s presentation was the OCT finding of hyperreflectivity at the level of the outer nuclear layer and outer plexiform layer. Hyperreflectivity at the level of the inner plexiform layer suggests paracentral acute middle maculopathy (PAMM), which is due to capillary occlusion of the middle retinal capillary plexus. PAMM has been associated with CRVO.(1) Less common in the setting of CRVO is occlusion of the deep retinal capillary plexus, which evidently occurred in our patient. Occlusion of the deep retinal capillary plexus has been associated with acute macular neuroretinopathy (AMN).(2) AMN was first reported in 1975 and was thought at that time to be an inflammatory condition.(3) Subsequently, There have been reports of AMN associated with CRVO.(2)
Anatomically, our patient responded well to Avastin treatment with resolution of the macular edema, but the vision did not improve significantly. This was likely due to the severe nonperfusion in the posterior pole.
1. Casalino G, William S, McAvoy C, Bandello F, Chakravarthy U. Optical coherence tomography angiography in paracentral acute middle maculopathy secondary to central retinal vein occlusion. Eye (Lond.) 2016;30:888-93.
2. Bhavsar RK, Lin S, Rahimy E, et al. Acute macular neuroretinopathy: A comprehensive review of the literature. Surv Ophthalmol. 2016;61:538-65.
3. Bos PJ, Deutman AF. Acute macular neuroretinopathy. Am J Ophthalmol. 1975;80:573-84.
