Toxic Retinopathies

Common toxic retinopathies:

• Antimalarials – chloroquine / hydroxycholoroquine

• Phenthiazines

• Tamoxifen

• Talc

Antimalarials:

• Maculopathy – once ‘bull’s eye retinopathy’ develops, it is irreversible.

• Management: Refer to RCOphth guidelines 2020.

• Quinine toxicity –> retinal oedema, fixed dilated pupils, attenuated arterioles, constricted visual fields & optic nerve atrophy.

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Phenothiazine:

• Medication for schizophrenia.

• Thioridazine (normal dose: 150-600mg/day) – >800mg/day few wks –> toxicity.

• Chlorpromazine (Largactil) (normal dose: 75-300mg/day) – >2400mg/day few wks –> toxicity

• Beginning – pigmentary changes – “salt and pepper” appearance –> geographic atrophy (late stages)

Tamoxifen:

• Anti oestrogen treatment for breast carcinoma.

• Usual dose is 20-40mg/day.

• Vortex keratopathy and optic neuritis – rare and reversible.

• Crystalline retinopathy.

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Talc maculopathy:

• Extent corresponds with amount and duration of drug abuse (cocaine or methylphenidate/Ritalin).

• Multiple tiny yellow-white glistening particles over posterior pole.

• Can lead to macular oedema, flame-shaped haemorrhages and arterial occlusion with talc emboli.

• Microtalc retinopathy – NFL defect like glaucoma.

• Refer to respiratory physician as ocular talc indicates lung function may be compromised.