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Chloroquine retinopathy in the rhesus monkey
Investigative Ophthalmology & Visual Science
|December 1, 1978
Summary
Long-term chloroquine administration in monkeys showed no clinical signs of retinal damage. However, extensive pathological changes occurred in the retina and choroid, despite normal ophthalmic appearance.
Area of Science:
- Ophthalmology
- Toxicology
- Pharmacology
Background:
- Chloroquine is an antimalarial drug with potential ocular toxicity.
- Previous studies have indicated a risk of retinopathy with long-term chloroquine use.
Purpose of the Study:
- To investigate the long-term ocular effects of intramuscular chloroquine administration in rhesus monkeys.
- To correlate drug accumulation in ocular tissues with pathological changes.
Main Methods:
- Rhesus monkeys received intramuscular chloroquine 5 days/week for up to 4.5 years.
- Ophthalmic examinations included clinical assessment, fluorescein angiography, and electrophysiology.
- Ocular tissues were analyzed for chloroquine and its byproducts.
Main Results:
- No clinical, angiographic, or electrophysiological evidence of retinal damage was observed during the study.
- Significant accumulation of chloroquine and its byproducts was found in pigmented ocular tissues (choroid, RPE, ciliary body, iris) and the retina.
- Extensive pathological changes, including degeneration of ganglion cells, photoreceptors, choroid, and retinal pigment epithelium, were observed despite normal ophthalmic appearance.
Conclusions:
- Intramuscular chloroquine can cause severe, progressive retinal and choroidal pathology in monkeys, even without overt clinical signs.
- Pigmented ocular tissues have a high binding capacity for chloroquine, leading to accumulation and subsequent damage.
- Ocular monitoring methods may not detect early-stage chloroquine-induced retinal damage.