Sir,

Amiodarone, a diiodinated benzofuran derivative, is used to treat patients with atrial and ventricular arrhythmias and angina pectoris.1, 2 Its use has been associated with numerous side effects including pulmonary fibrosis, thyroid dysfunction, gastrointestinal problems, neuropathy, dermatopathy, and ocular effects.1, 3, 4, 5 Ocular changes caused by amiodarone may involve the lens, the retina, the optic nerve, and more commonly the cornea.3, 5, 6, 7 Amiodarone keratopathy (AK) has a prevalence of 70–100%, but only 10% of patients experience visual disturbances.6, 7 AK is typically bilateral.3, 6, 8 We report an unusual case of unilateral AK in a patient using an occlusive contact lens in the contralateral eye.

Case report

A 67-year-old male patient who had been using an occlusive contact lens (Optifree Xpress) for 5 years was reviewed to evaluate the status of the cornea. The occlusive contact lens had been prescribed for the left eye to prevent troublesome diplopia, which could not be controlled with prisms (Figure 1a). He had a past ocular history of thyroid eye disease treated with systemic corticosteroids, orbital radiotherapy, and adjustable suture squint surgery. He had paroxysmal atrial fibrillation (AF), which had been well controlled for the past 2 years with amiodarone 400 mg/day.

Figure 1
figure 1

(a) Occlusive contact lens in situ in left eye. (b) Amiodarone keratopathy in the right eye: the verticillate, whorl-like greyish golden brown epithelial deposits are seen extending into the visual axis. (c) Photograph of left healthy cornea with no evidence of amiodarone keratopathy.

Full size image

On examination, the visual acuity was 6/5 unaided in both eyes. There were greyish brown corneal epithelial opacities in a verticillate, whorl-like pattern occupying the right inferior cornea and extending into the visual axis, a picture consistent with amiodarone keratopathy (Figure 1B). The left cornea was clear (Figure 1C). Visually the patient was asymptomatic and he was advised to continue with his CL use.

Comment

Amiodarone keratopathy was classified by Orlando et al6 in 1984 into four grades: grade 1 describes fine greyish golden-brown opacities in the epithelium at the inferior pupillary margin; grade 2 is characterized by a more linear pattern extending towards the limbus; grade 3 is characterized by extension of the lesion into a verticillate, whorl-like pattern that may involve the visual axis; grade 4 describes additional ‘clumps’ of golden-brown deposits. These four grades represent an orderly progression and appear to directly correlate with dosage and duration of amiodarone therapy.6, 9

Histologically, these deposits represent intracytoplasmic lysosomal-like inclusions of membranous lamellar bodies within the basal epithelial cells.7 Some investigators believe that these inclusions represent lipofuscin, others that they are drug–lipid complexes.7, 9 More recently, in vivo confocal microscopy has shown that amiodarone keratopathy may involve deeper corneal layers including the stroma and endothelium.10

AK usually appears simultaneously in both eyes.3, 6, 8 It is unlikely that the unilaterality of our patient's keratopathy was a result of early asymmetry as he had been on a moderate dose of amiodarone for 2 years. Patients on amiodarone are known to develop photosensitivity and cutaneous pigmentation.1, 4 We propose that the occlusive contact lens and the resultant lack of exposure to ultraviolet light prevented the keratopathy in the contralateral eye. In a previous case series, asymmetrical AK was reported in a patient with unilateral ptosis.4 Ultraviolet radiation may produce a phototoxic reaction which promotes the binding of the drug or its metabolites to the corneal tissue. Protective measures such as the use of sunhats and sunglasses may prevent the development of AK.