DISCUSSION

    PORN is an established variant of necrotizing zoster retinopathy occurring in immunocompromised individuals. It is associated with primary optic neuritis in 20% of cases.

    The main threat to vision is extensive retinal necrosis with resultant retinal detachment, occurring in 70% of eyes and associated with negative prognosis for vision. As a cause of poor visual outcome, optic neuritis occurs in <20% of eyes. CRAO and CRVO are much rarer complications seen in 7% of eyes, but have never been reported previously as combined complications[1].

    Many treatment regimes including intravenous Ganciclovir, Foscarnet, and Acyclovir have been described as monotherapy or in combination. Acyclovir monotherapy results are poor with 90% NLP final acuity[1,2]. Aggresive Ganciclovir therapy alone or in combination with Foscarnet have been described as having lower rates of NLP acuity (34%) than Foscarnet or Acyclovir alone[3]. In spite of these successes, treatment failure and recurrence are the norm[3]. The efficacy of combined

    Figure 1PORN with primary optic neuritis complicated by combined secondary CRAO and CRVO

    Figure 2Fundal fluorescein angiography: delayed filling of retinal arterial (armª²artery time of 90 seconds) and venous vasculatures (arterioª²venous transit time of 7 minutes and 30 seconds)

    Figure 3Panª²Retinal Photocoagulation: quiescence of PORN, however vision remained NLP

    intravitreal and intravenous antiviral therapy has yet to be established.

    Bilateral involvement is common, seen in 50% of cases at diagnosis, and 83% sequential involvement[3]. Prophylaxis for the unaffected eye is controversial, except to confer some degree of temporal protection from disease reª²activation in the affected eye. Although oral Acyclovir has been described for the treatment of Acute Retinal Necrosis and Zoster infections at other sites in the body, no controlled therapeutic trials support these practices[4].

    Prognosis of PORN is poor, with patients¬ð visual acuity of

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  1 Engstrom RE Jr, Holland GN, Margolis TP ,Muccioli C, Lindley JI, Belfort R Jr, Holland SP, Johnston WH, Wolitz RA, Kreiger AE. The progressive outer retinal necrosis syndrome: a variant of necrotizing herpetic retinopathy in patients with AIDS. Ophthalmology1994;101(9): 1488ª²1502

2 Ciulla TA, Rutledge BK, Morley MG, Duker JS. The progressive outer retinal necrosis syndrome: successful treatment with combination antiviral therapy. Ophthalmic Surg Lasers1998;29(3):198ª²206

3 Moorthy RS, Weinberg DV, Teich SA , Berger BB, Minturn JT, Kumar S, Rao NA, Fowell SM, Loose IA, Jampol LM. Management of varicella zoster virus retinitis in AIDS. Br J Ophthalmol 1997;81(3):189ª²194

4 Keating MR. Antiviral agents. Mayo Clin Proc 1992; 67(2): 160ª²178

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