Vortex keratopathy (cornea verticillata)

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  Signs: (a) fine greyish or golden-brown opacities in the inferior corneal epithelium, (b) progressing to a whorl-like pattern that originates from a point below the pupil and swirls outwards, sparing the limbus ( Fig. 20.1 ); usually reversible on cessation of medication. Vision is not impaired, but some patients may experience haloes.

  
  

  
  

  
  

  

  
  
  
  
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  Causes: quinolone antimalarials (chloroquine, hydroxychloroquine) and amiodarone.

Chlorpromazine

Long-term therapy may cause subtle and visually innocuous yellowish-brown granular deposits in the endothelium, Descemet’s membrane, and deep stroma.

Argyrosis

Keratopathy in argyrosis (silver deposition) is characterized by greyish-brown granular deposits in Descemet’s membrane ( Fig. 20.2 ); conjunctival involvement may also occur ( Fig. 20.3 ).

Chrysiasis

Chrysiasis describes the deposition of gold in tissues after prolonged administration (chrysotherapy), usually in the treatment of rheumatoid arthritis. Keratopathy is characterized by asymptomatic dust-like or glittering purple granules scattered throughout the epithelium and stroma.

Amantadine

Soon after commencement of therapy, some patients develop reversible diffuse white punctate opacities sometimes associated with epithelial oedema.

Steroids

Both systemic and topical steroids are cataractogenic. The relationship between dose and duration of systemic administration and cataract formation is unclear. Opacities are initially posterior subcapsular ( Fig. 20.4 ) and later anterior subcapsular; early opacities may sometimes regress if therapy is discontinued, but progression commonly occurs despite withdrawal.

Other drugs

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  Chlorpromazine: fine stellate yellowish-brown granules on the anterior lens capsule within the pupillary area ( Fig. 20.5 ) develop in 50% of patients who have received a cumulative dose of 1000 g. The deposits persist despite discontinuation of therapy, but are visually innocuous.

  
  

  
  

  
  

  

  
  
  
  
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  Busulphan: occasionally causes lens opacities.

  
  
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  Gold: innocuous anterior capsular deposits in approximately 50% of patients treated for more than 3 years.

  
  
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  Allopurinol: increases the risk of cataract formation in elderly patients with large cumulative doses.

Rifabutin

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  Acute anterior uveitis, typically unilateral and frequently associated with hypopyon; associated vitritis may be mistaken for endophthalmitis. Treatment involves withdrawal of the drug or reduction of dose.

  
  
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  Drugs that inhibit metabolism of rifabutin (e.g. clarithromycin, fluconazole) increase the risk of uveitis.

Cidofovir

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  Acute anterior uveitis with few cells but a marked fibrinous exudate may develop following several intravenous infusions; vitritis is common and hypopyon may occur with long-term administration.

  
  
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  Treatment with topical steroids and mydriatics is usually successful, avoiding the need to discontinue therapy.