Eruption severity and characteristics in herpes zoster ophthalmicus: correlation with visual outcome, ocular complications, and postherpetic neuralgia.

INTRODUCTION: Herpes zoster ophthalmicus (HZO) is characterized by a typical vesicular eruption affecting the distribution of the ophthalmic division of the trigeminal nerve which can be of varying severity. The correlation of eruption severity and ocular involvement and subsequent visual loss is still to be established. In this prospective longitudinal study we evaluated the correlation of eruption severity with ocular complications, visual outcome and postherpetic neuralgia.
METHODS: Patients with HZO underwent detailed ophthalmological and dermatological examination at presentation and follow-up on 1(st) , 2(nd) and 4(th) week and 3(rd) and 6(th) month. Eruption severity was graded as mild, moderate and severe based on the number of vesicles. The correlation of eruption severity and distribution with ocular complications, visual outcome and postherpetic neuralgia was statistically evaluated.
RESULTS: Severe eruption was seen in 14(28%), moderate eruption in 21(42%) and mild eruption in 15(30%). Severe eruption was significantly associated with increased incidence and severity of ocular involvement (p = 0.04 and p = 0.04 respectively), occurrence of uveitis (p = 0.004), reduced visual outcome (p = 0.002) and the occurrence of PHN (p = 0.05). Lacrimal nerve involvement was also associated with increased incidence (p = 0.03) and severity (p = 0.02) of ocular complications and visual loss (p = 0.01).
CONCLUSION: Increasing eruption severity is a good predictor of occurrence of ocular complications and subsequent visual loss in HZO. Presence of a severe eruption is an indication for early ophthalmic intervention. Nasociliary nerve and lacrimal nerve involvement are also good predictors of ocular complications.