Sir,

Smallpox is caused by infection with the orthopoxvirus variola.1 Declared eradicated by the World Health Assembly in 1980,2 smallpox has been reported to be associated with early ocular complications in 5–10% of patients. Typical early ocular complications of variola infection included periocular and conjunctival pustules, conjunctival phlyctenuels, ulcerative keratitis, and iritis.1 Scar formation after acute corneal infection was the most common cause of vision loss in patients with smallpox, accounting for up to one-third of all blindness in Europe before the introduction of an effective vaccine.3 Although studies from the early part of the twentieth century reported focal areas of iris atrophy termed vitiligo irides as a late complication in up to 50% of patients with smallpox,4 few reports have provided a detailed description of this finding5 and none have provided high-quality photographic images.

Case report

We describe seven patients who were found to have multifocal vitiligo iridis in one eye or in both, 37–60 years after a history of smallpox infection (Table 1). The areas of iris atrophy varied in size (Figure 1) and were bilateral in five of the seven (71.4%) patients (Table 1). Past ocular history was otherwise notable for varying degrees of nuclear sclerotic cataract in all seven patients and for mild myopia in one patient. No patient had a history or signs of herpetic eye disease, or of previous eye trauma or surgery.

Table 1 Clinical characteristics of patients with multifocal vitiligo iridis and a remote history of smallpox infection
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Figure 1
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Slit-lamp photographs showing multifocal vitiligo iridis in seven patients (cases A–G) with a remote history of smallpox infection.

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Comment

Although 2010 marks the thirtieth anniversary of the global eradication of smallpox, as recently as 1967 when the World Health Organization (WHO) launched an intensified plan to eradicate the disease, variola virus was estimated to infect 15 million people annually worldwide (WHO Smallpox Factsheet; http://www.who.int/mediacentre/factsheets/smallpox/en/). Three of every four people infected with smallpox survived, and so a large number of those infected before 1980 still survive, particularly in Africa and Asia, including India. Many of these patients are now approaching an age when they might be expected to seek eye care, most commonly for cataract, as in our cohort. The recognition of vitiligo iridis as a late complication in patients with a remote history of smallpox infection is therefore important to help prevent misdiagnosis as an unrelated cause of focal or multifocal iris atrophy, most notably herpetic eye disease.