Eyeworld

91 EW INTERNATIONAL February 2015 by Matt Young and Gloria D. Gamat EyeWorld Contributing Writers Rare retinal condition continues to puzzle, but there are ways to treat I t was called Kirisawa uveitis when first described in the Japanese literature in 1971. Since then, acute retinal necrosis (ARN) syndrome has puzzled ophthalmologists. ARN is an extremely rare con- dition with characteristic fundal appearances that nevertheless troubles eye specialists because of its potential to become a visually devastating condition for those affected. ARN can lead to uveitis, retinal detachment, and blindness. Its incidence rate is estimated at 1 case per 2 million people per year, as reported in recent years by surveys from the U.K. In the past 3 decades, the literature on the diagnosis and management of ARN has expanded, and the understanding, diagnosis, and management (both medical and surgical) of the condition have also improved. The uveitis that puzzles Although an immunogenetic predisposition to the disease is being suggested by various studies, ARN is largely a result of dormant herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), or varicella-herpes zoster virus (VZV) reactivation in the retina. However, the exact etiology of such a reacti- vation remains a puzzle. VZV is the causative agent in 70% of ARN cases, while HSV is in 30% of the cases. Typically, ARN occurs in young immunocompetent individuals, 20 to 50 years of age; the age of mani- festation depends on the causative agent. Data published in the Ameri- can Journal of Ophthalmology by JB Ganatra and colleagues in 2000 suggested that VZV or HSV-1 causes ARN in patients older than 25 years, whereas HSV-2 causes ARN in patients younger than 25 years. The study looked into the viral causes of ARN with respect to patient age and central nervous system disease. Additionally, a history of central nervous system infection in an ARN patient suggests that herpes simplex virus is likely to be the viral cause. Challenges in the management of acute retinal necrosis troversial case of ARN at the recent National Healthcare Group Eye immunosuppresion," said Stephen Teoh, MD, director of vitreoretina surgery at the Eagle Eye Centre, Singapore, who presented a con- "The pathogenesis occurs in young, apparently healthy adults with no other systemic illness, usually not in any other form of continued on page 92 Temporal retinitis with defined white edges and hazy view due to dense overlying vitritis. Source (all): Stephen Teoh, MD Montage photos showing peripheral acute retinal necrosis with typical whitish retinitis with scalloped edges and adjacent vasculitis.

• Cover