EyeWorld Asia-Pacific September 2016 Issue

September 2016 12 EWAP FEATURE anterior chamber inflammation, often with hypopyon, are characteristic. Conversely, HORV is painless with a relatively quiet anterior chamber. Moderate to severe vitritis, with minimal to no view of the retina, is typical of endophthalmitis, while in HORV, the vitreous is usually minimally inflamed with a clear view to the retina. Although retinal vasculitis and hemorrhage can accompany severe bacterial endophthalmitis (e.g., Streptococcus species), the retina in these cases can only be visualized once the anterior chamber and vitreous have been surgically cleared of dense inflammatory infiltrate. Viral retinitis is almost always caused by a member of the Herpesviridae family. HSV and VZV are the most common causes of acute retinal necrosis (ARN), which may present with rapidly progressive retinal vasculitis. The retinitis and moderate to severe vitritis that characterize ARN are not seen in HORV. HORV often features large patches of retinal hemorrhage that are uncommon with ARN. CMV retinitis may cause more intraretinal hemorrhage than ARN, but is usually slowly progressive unless the patient is severely immunocompromised. Finally, viral retinitis is not typically associated with an intraocular procedure, which is a requisite feature of HORV. Medication toxicity after cataract surgery can cause TASS and/or retinal vascular occlusion. Intraocular aminoglycosides are known to be potentially toxic to the retina at standard doses; retinal toxicity has also been more recently reported with inadvertent intracameral injection of high doses of cefuroxime. The presentation and appearance of medication toxicity after cataract surgery differs from HORV. In medication toxicity, patients usually have poor visual acuity immediately after surgery (on postoperative day 1), while HORV has a delayed onset. Patients with retinal toxicity due to high doses of cefuroxime often have accompanying TASS and severe corneal edema immediately after surgery, which are not features of HORV. In aminoglycoside toxicity, the macula is commonly involved, while peripheral retinal vascular occlusion is unusual. Conversely, in HORV, all cases had peripheral involvement (and more severe cases of HORV also had macular ischemia and whitening). CRVO (or combined CRVO/ CRAO) after cataract surgery may be due to an intraocular pressure spike during surgery, or a complication from a retrobulbar block, and patients usually present immediately on postoperative day 1 with severe visual loss. Conversely, patients with HORV present on average 8 days after cataract surgery, with an unremarkable examination on postop day 1. CRVO after cataract surgery is unilateral, while HORV is usually bilateral and sequential if bilateral sequential cataract surgery is performed. Even if the second eye surgery is delayed, HORV occurs in the second eye (and presents in a strikingly similar fashion to the first eye), distinguishing HORV from postoperative CRVO. The fundus appearance of HORV is also different than in CRVO. The hemorrhages in HORV often appear in large patches, and only occur in regions of vascular occlusion, often along retinal venules. In contrast, CRVO features diffuse, smaller dot/blot hemorrhages, even in areas that are not ischemic. Post-cataract CRVO hemorrhages typically resolve gradually, particularly with anti-VEGF injections, but persist for months despite treatment with HORV. Retinal veins are significantly dilated and tortuous with CRVO, but not in HORV. In HORV, the peripheral retinal vessels were always occluded in our series, while the posterior retinal anatomy appeared normal in less severe cases. This appearance is not typical of CRVO. Regarding etiology, the Task Force consulted with allergists and immunologists to determine a Joint - from page 10 A 68-year-old woman presented with decreased vision 10 days after otherwise uncomplicated unilateral cataract surgery; intracameral vancomycin (1 mg/0.1 ml) was used at the end of the case. Despite treatment with systemic corticosteroids, valacyclovir, PRP, and anti-VEGF injections, visual outcome was counting fingers at 1 foot. Image A: Widefield color photograph demonstrates diffuse peripheral retinal vascular occlusion and associated large patches of retinal hemorrhage following the retinal venules. Ischemic macular whitening is evident. The retinal veins are not tortuous or dilated. Image B: Widefield FA demonstrates retinal vascular occlusion in areas of retinal hemorrhage. Staining of retinal venules is evident. Source: Rahul Mandiga, MD