Toxic Retinopathy
Retinal changes resulting from use of
medications.
Toxic retinopathy is rare.
Toxic retinopathy can remain asymptomatic for a long time.
Loss of visual acuity occurs if the macula is
affected.
Chloroquine in doses exceeding 250 g causes retinal damage. Macularedema can
occur initially. Later, punctate pigment epithelial changes develop, which may
progress to bull’s eye maculopathy with concentric rings of hypopigmentation
and hyperpigmentation in the macular region (Fig. 12.32). These findings are usually bilateral and symmetrical. Other
toxic retinal changes are listed in the appendix.
The diagnosis is made by binocular ophthalmos-copy with the
pupil dilated and confirmed by electrophysiologic studies that include an
electroretinogram, electro-oculogram, and visual evoked poten-tials (see Fig.
12.2a).
Retinal pigment epithelium or retinal bleeding canresult from many other retinal disorders, and may also be associated with the underlying disease for which the medication was prescribed.
The medication should be discontinued if possible.
Regular ophthalmologic follow-up examinations are
indicatedbefore and during treatment that involves medications with known
ocular side effects.
The clinical course depends on the specificmedication and dose.
Findings may improve after the medication is discon-tinued. However, with
chloroquine in particular, findings may continue to worsen even years later.
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