Table of Contents
Chloroquine and Hydroxychloroquine Screening Procedures
Risk
- Risk increases in the following:
- After 5 years of use
- Hydroxycholoroquine Daily dose >5.0mg/kg real weight
- Cholorquine Daily dose >2.3 mg/kg real weight
- Renal disease- subnormal glomerular filtration rate
- Tamoxifen use
- Preexisting macular disease
- Risk may be higher than previously believed as more sensitive testing employed (OCT, MERG)
Toxicity
- Irreversible Toxicity as evidenced by perimacular retinal thinning, photoreceptor and RPE loss
- Early signs are loss of outer segment structural lines and increased parafoveal autofluorescence
Timeline
- Baseline Examination within first year of use
- Annual Screening after 5 years of use if on acceptable doses without other risk factors
Recommended Screening Procedures
Ocular Exam
- Dilated Retinal Exam (low sensitivity)
Automated Visual Field
- White 10-2
- Interpret with a low threshold for abnormality
- Retest if abnormalities appear
One or More Objective Tests (abnormalities may be before field loss)
- SD-OCT
- Cross section of macula
- localized thinning of parafoveal region especially the outer-segments and RPE structural lines
- loss of the inner-/outer-segment line may be early sign
- mfERG
- Especially in suspicious or unreliable visual field loss
- Paracentral voltage reduction
- Fundus Autofluorescence
- Increased autofluorescence possibly from accumulation of outersegment debris
Tests NOT recommended for screening
- Fundus photography
- Time-Domain OCT
- Fluorescein Angiography- not proved to be more senstive than other tests
- Full-field ERG- may be useful in those with manifest toxicity to evaluate degree of damage
- Amsler grid
- EOG