Eyeworld

EW NEWS & OPINION 8 July 2016 Neovascular glaucoma developed rapidly in 19 of 36 eyes (53%), often within 1–2 months. Seven of 36 eyes (19%) received an additional bolus of intravitreal vancomycin for treatment of presumed bacterial endophthalmitis. These patients had particularly poor outcomes; 5/7 of these eyes were NLP. There are currently 11 other cases of possible HORV for which we have not been able to collect a full data set or images, and all but 2 of these received intraocular vanco- mycin. We don't think the latter 2 represent true HORV based on the information given to us so far. One case had poor vision starting on POD 1 and may represent medi- cation toxicity with severe diffuse retinal microvascular occlusion with sparing of the larger retinal vessels. The second case looks more like a CRVO or combined CRAO/CRVO, with dilated and tortuous retinal veins and diffuse scattered small dot hemorrhages. The differential diagnosis of HORV includes acute postoperative endophthalmitis, viral retinitis, medication toxicity, and CRVO or combined CRAO/CRVO. In endoph- thalmitis, pain and severe anteri- or 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 mini- mally inflamed with a clear view to the retina. Although retinal vasculi- tis 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 vit- reous have been surgically cleared of dense inflammatory infiltrate. Viral retinitis is almost always caused by a member of the Herpes- viridae 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 char- acterize ARN are not seen in HORV. HORV often features large patches of retinal hemorrhage that are uncom- mon with ARN. CMV retinitis may cause more intraretinal hemorrhage than ARN, but is usually slowly pro- gressive unless the patient is severely immunocompromised. Finally, viral retinitis is not typically associat- ed with an intraocular procedure, which is a requisite feature of HORV. Medication toxicity after cata- ract surgery can cause TASS and/or retinal vascular occlusion. Intraoc- ular aminoglycosides are known to be potentially toxic to the retina at standard doses; retinal toxicity has also been more recently reported with inadvertent intracameral in- jection of high doses of cefuroxime. The presentation and appearance of medication toxicity after cata- ract 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 complica- tion 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 oc- clusion, 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, particu- larly with anti-VEGF injections, but persist for months despite treat- ment 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 po- tential mechanism. Considering that vancomycin was the only surgical adjuvant in common used in all 36 eyes of 22 patients in our current series, the conclusion was that this is the most likely culprit. The timing of HORV is consistent with a type III hypersensitivity similar to leuko- cytoclastic vasculitis, a potentially analogous reaction in the skin that has been seen rarely with systemic vancomycin. In addition, type III Joint ASCRS/ASRS continued from page 3 continued on page 16 Bilateral hemorrhagic occlusive retinal vasculitis in a 55-year-old man after cataract surgery with intracameral vancomycin 18 days (right eye) and 11 days (left eye) prior to presentation. Vision is 20/30 in the right eye (A) and no light perception in the left (B). Note the severe peripheral ischemia in the right eye (C) and complete non-perfusion in the left eye (D) on fluorescein angiography. Source: Ryan Terribilini A B C D

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