Acute retinal necrosis: the effects of intravitreal foscarnet and virus type on outcome

To study the effects of intravitreal foscarnet and the clinical differences between varicella zoster virus (VZV) and herpes simplex virus (HSV) induced acute retinal necrosis (ARN).

Retrospective comparative case series.

Eighty-one eyes of 74 patients.

A retrospective case note analysis was performed in 2 tertiary referral centers.

Presenting and final visual acuity, and progression to retinal detachment.

Thirty-three eyes had HSV-ARN and 48 had VZV-ARN. The average age for HSV-ARN was 34 years and 51 for VZV-ARN (P<0.001). Visual acuity on presentation was similar (P = 0.48), but a larger proportion had better vision (> or =20/60) in the HSV-ARN group (52%) than the VZV-ARN group (35%). A greater proportion of eyes with poor vision (< or =20/200) was found at the 12-month follow-up in the VZV-ARN group (60%) compared with the HSV-ARN group (35%). A greater degree of visual loss in the VZV-ARN group (0.4 logarithm of the minimum angle of resolution [logMAR]) compared with the HSV-ARN group (0.04 logMAR) was detected (P = 0.016). Retinal detachment was 2.5-fold more common in VZV-ARN (62%) compared with HSV-ARN (24%). When comparing eyes treated with (n = 56) and without (n = 25) intravitreal foscarnet, there was a 40% lower rate in retinal detachment (53.6% vs 75.0%) for VZV-ARN (P = 0.23). The numbers with HSV-ARN were too small for analysis.

The results support the difference of outcome in HSV-ARN and VZV-ARN. Therefore, viral identification serves as a key to predicting outcome in these patients. Intravitreal foscarnet seems to be a useful adjunct for the treatment of ARN in that it reduced rate of retinal detachment.