Chloroquine, Hydroxychloroquine and Retinal Toxicity: Are Ophthalmologists Concerned?

1. The primary determinants of risk of retinopathy with use of Chloroquine (CQ) and Hydroxychloroquine (HCQ) :
   • Dose (≤5.0 mg/kg/day)
   • Weight (real patient weight)
   • Duration of treatment¹
2. There is a risk of retinal toxicity after long-term use. At the AAO*’s recommended dose of ≤5.0 mg/kg/day(real weight), patients have less than 1% risk in the first 5 years of therapy and less than 2% up to 10 years. The risk increases to 20% after 20 years. Risks are much greater with higher doses.²
3. The proposed doses to treat COVID-19 are actually 4-5 greater but used very briefly. Based on Marmor et al.’s recent article, extreme doses of CQ/HCQ do accelerate retinal damage, but more probable after many months rather than days.¹
4. If these drugs are suggest to be used for >1 year, annual screening should be considered.¹
5. Retinopathy is not of serious concern regarding CQ/HCQ usage during the pandemic, but as new treatment protocols emerge, risk of retinopathy should still be carefully studied.¹

This data mainly comes from the analysis of the article by “COVID-19 and Chloroquine/Hydroxychloroquine: Is There Ophthalmological Concern?” by Marmor et al, that analyzes the risk of retinal toxicity in light of its usage during the pandemic.

Sources:

1. Marmor, M. F. (2020). COVID-19 and Chloroquine/Hydroxychloroquine: Is There Ophthalmological Concern? American Journal of Ophthalmology. doi: 10.1016/j.ajo.2020.03.029
2. Marmor, M. F., Kellner, U., Lai, T. Y., Melles, R. B., & Mieler, W. F. (2016). Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy (2016 Revision).Ophthalmology, 123(6), 1386–1394. doi: 10.1016/j.ophtha.2016.01.058

*AAO = American Academy of Ophthalmology