Microsoft word - hydroxychloroquine_and_ocular_toxicity_final oct 2009.doc

The Royal College of Ophthalmologists
Hydroxychloroquine and Ocular Toxicity
Recommendations on Screening
October 2009
  The Royal College of Ophthalmologists 2009 All rights reserved For permission to reproduce any of the content contained herein please contact events@rcophth.ac.uk  The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009 Hydroxychloroquine and Ocular Toxicity
Recommendations on Screening
(Replacing the Royal College of Ophthalmologists Guidelines for Screening 2004
and 1998)

Background
Hydroxychloroquine is a quinolone used primarily by rheumatologists for rheumatoid
arthritis and systemic lupus erythematosus, and by dermatologists for cutaneous lupus.
Although its mechanism of action is not fully understood, it is thought to increase pH
within intracellular vacuoles, which probably interferes with antigen processing in
macrophages and other antigen-presenting cells, thereby down-regulating the immune
response against auto-antigenic peptides1. Chloroquine works in a similar way and is
used for similar clinical indications although much less frequently. Its use in the
prophylaxis and treatment of malaria is diminishing because of widespread resistance.
Systemic side effects of hydroxychloroquine and chloroquine include disturbances in
hepatic and renal function. Ocular side effects include retinal toxicity (which can lead to
permanent visual impairment) and deposition of the drug in the cornea. The
mechanism of retinal toxicity is not well understood, though it appears that the earliest
changes occur in the cytoplasm of ganglion cells and photoreceptors with later
involvement of the retinal pigment epithelium2, where it binds to melanin.
Hydroxychloroquine has been used since the 1960s, and although it appears to be
considerably less toxic to the retina than chloroquine, possibly because chloroquine
crosses the blood-retinal barrier more easily3, a similar pattern of retinopathy has been
observed with both drugs.
The incidence of clinically significant hydroxychloroquine retinopathy appears to be very
low with only 50 cases identified in a literature review to May 20054 and it has been
estimated that at least one million patients have been treated with quinolones during the
same time period5. In the largest single series, one patient out of 1207 developed
retinopathy after 7 years6. In a prospective study of patients taking within the maximum
recommended dose of 6.5mg per kg of lean body weight7, the incidence of irreversible
hydroxychloroquine retinopathy was 2 cases in 400 patients, both of whom received
treatment for over 6 years. Maximum daily dosage and duration of treatment appear
to be more important determinants of the risk of toxicity than cumulative dosage6-9
The risk of retinal toxicity with chloroquine appears to be significantly higher than with
hydroxychloroquine, and the safe daily dose and cumulative dose is less clear6,7. For
this reason, chloroquine should only be considered if other drugs have failed to control
the disease adequately. It is recommended that all patients taking chloroquine should
be counselled on the risk of central visual field loss and ophthalmic examination should
be arranged locally between the prescribing physician and the ophthalmologist.
The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009
Clinical features of ocular complications
Quinolones can precipitate in the corneal epithelium in a diffuse punctate or whorl-like
pattern which can sometimes result in visual haloes. This is much less common with
hydroxychloroquine than with chloroquine4,8. The effect is reversible on stopping the
drug.
The earliest sign of retinal toxicity is fine pigmentary stippling of the macula and loss of
the foveal light reflex, sometimes referred to as premaculopathy. This may progress to
the development of an annular zone of depigmentation of the retinal pigment epithelium
surrounding the fovea (“bulls-eye” maculopathy) with a corresponding perifoveal visual
field defect. If treatment continues, the pigment epithelial atrophy may become
generalised with loss of visual acuity and peripheral visual field loss5. Even if treatment
is stopped, areas of pigment epithelial atrophy may continue to increase for a time
before stablilising7.
The appearances of premaculopathy and “bulls-eye” maculopathy are not specific to
quinolone toxicity and can be seen in the “dry” form of age-related macular
degeneration and in a number of retinal dystrophies.
Early detection of hydroxychloroquine retinopathy
By the time pigmentary changes at the macula are visible ophthalmoscopically, it is
almost certain that some degree of irreversible damage will already have occurred.
There has been considerable interest, therefore, as to whether it is possible to detect
subtle effects of toxicity at a reversible stage.
Static perimetry of the central 10 degrees of vision (for instance the Humphrey 10:2
protocol) can detect small paracentral visual field defects, but is fairly time consuming to
perform, is not widely available outside hospital eye clinics and it is a demanding test
which depends on the subject maintaining steady fixation and concentration.
The Amsler Chart is a grid of squares printed on paper with a central fixation dot. It is
viewed monocularly at 30cm (with reading glasses if required) and a visual field defect
within the central few degrees of vision may be seen as a blank or distorted area
superimposed on the grid, where it can be plotted. The attraction of the test is that it is
cheap to perform and can easily be self-administered. The most commonly used
Amsler chart is a black grid printed on white paper, but a red grid printed on black paper
is also available and may be more sensitive. One study reported that 25 of a sample of
56 patients taking hydroxychloroquine had one or more detectable scotomata when
viewing the Amsler chart under conditions of reduced illumination using cross-polarizing
filters (of which 5 were detected with the red Amsler chart and 2 with the standard
Amsler chart)10. However, it is not clear whether these apparent field defects were
reproducible by other means or whether any progression of the field defects occurred
subsequently, and there was no estimate of the specificity of the test11.
The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009 Multifocal electroretinography (mfERG) involves the projection of an array of hexagonal
light sources onto the retina. Each hexagon flashes on and off independently of the
others in a pseudo-random binary sequence and the electroretinographic signal from
the area of the retina stimulated by each hexagon is extracted by the mathematical
technique of kernel analysis. In a cohort of 12 patients receiving hydroxychloroquine,
mildly reduced mean mfERG amplitudes were found when compared to age-matched
controls. Three patients who stopped treatment appeared to show some recovery in
responses.12. However, no patient had clinical evidence of maculopathy and the
reduction in mfERG responses was small in comparison to the inter-test variability of the
mfERG13. It has not yet been established whether changes in the mfERG predict the
development of clinically significant hydroxychloroquine retinopathy.
The property of lipofuscin in the retinal pigment epithelium to fluoresce when stimulated
with monochromatic light at a wavelength of 488nm is used in the technique of fundus
autofluorescence (FAF) imaging. The fundus is imaged with a scanning laser
ophthalmoscope through a barrier filter which blocks wavelengths below 495nm. FAF
provides an indirect measure of the activity of the photoreceptors and the retinal
pigment epithelium. A cohort of 25 patients on long term quinolones was examined
using FAF. 10 of 19 patients taking chloroquine for 2-20 years had abnormalities of
FAF, whereas 6 patients taking hydroxychloroquine for 1.3-19 years all had normal FAF
appearances14, providing additional evidence that hydroxychloroquine is safer than
chloroquine.
Is there a case for systematic screening for ocular toxicity?
To justify a systematic programme of screening for hydroxychloroquine toxicity, it is
necessary to demonstrate:
1. That there is a causal relationship between the drug and the adverse effect
2. That a test or a combination of tests is capable of detecting toxicity at a reversible
stage with acceptable levels of sensitivity and specificity
3. That an intervention (e.g. stopping the drug) prevents the development of irreversible
retinal damage
4. That the process of screening is acceptable to patients and that the benefits of
screening outweigh any risks.
If all four conditions are met, it is also necessary to introduce an economic evaluation
(the cost of one case of visual loss prevented). Possible risks of screening include
causing unnecessary anxiety to patients, a burden of unnecessary appointments on the
health economy and lost opportunity to benefit from treatment for patients incorrectly
identified as being at risk15.
Although the reviewing group accepts that there is a link between hydroxychloroquine
use and retinal toxicity, it does not believe that the available evidence supports the
introduction of a programme of systematic screening for hydroxychloroquine toxicity at
the present time because clinically significant maculopathy is very rare and there is
currently no reliable test for detecting it at a reversible stage.
The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009
Recommendations for good practice in rheumatology and dermatology clinics

 The maximum dosage of hydroxychloroquine should not exceed 6.5mg / kg lean body weight (typically 200-400 mg daily); if the patient is overweight, check lean body weight with a body mass index calculator.  Establish renal and liver function at baseline assessment  Enquire about any visual impairment which is not corrected with spectacles  Record reading performance with each eye with a reading spectacle correction if worn, using a near vision test type, at baseline and at annual review (see Appendix 1).  If the patient can read a small print size such as N8 or N6 at baseline assessment, treatment with hydroxychloroquine can be commenced.
Although the use of Amsler Charts has not been validated in rheumatology and
dermatology clinics, the specimen patient information chart in Appendix 2 contains
instructions for self-administration of the Amsler test and the patient may be issued with
the instructions and an Amsler Chart (either black on white or red on black).
If visual impairment is suspected, the patient should be advised to consult an
optometrist in the first instance. If any apparent impairment is correctable with
refraction, treatment may then commence. Any relevant abnormality detected by the
optometrist would be referred to an ophthalmologist in the usual way.
Referral to an ophthalmologist
This is appropriate if any patient:
 Has visual impairment or eye disease detected at baseline assessment (confirmed by an optometrist). It should be noted that in elderly patients there is often coincidental ocular morbidity from cataract, glaucoma and age-related maculopathy.  Notices reduced vision (particularly for reading), patchy central vision or distorted central vision whilst on treatment. Patients should be warned to seek advice from the prescriber (as abrupt withdrawal of treatment may provoke a flare-up of their inflammatory disease) and to have their vision checked by an optometrist. Although quinolones are not licensed for children, they are used in specialist units particularly in the management of juvenile idiopathic arthritis, systemic lupus erythematosus and fibrosing alveolitis. Some of these children will already be attending an ophthalmologist for monitoring for the development of uveitis. Little is known about ocular toxicity of hydroxychloroquine in children, and it is recommended that locally agreed protocols should be established between the prescriber and ophthalmologist for such children. The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009 Examination by the ophthalmologist
The assessment should include:
 Enquiry about any disturbance of central vision  Central visual field, using an Amsler Chart (preferably red on black) or automated perimetry (e.g. Humphrey 10-2 protocol).  Stereoscopic slit lamp examination of the retina (e.g. with a 90D or 78 biconvex
Evaluation may need to be extended according to signs and symptoms to include retinal
photography, ocular coherence tomography (OCT), fundus autofluorescence (FAF)
imaging and visual electrophysiological tests.
Subsequent examinations should be at the discretion of the ophthalmologist, but
indefinite follow up is not likely to be required for most patients. For patients who have
received continuous treatment for more than 5 years, an individual arrangement should
be agreed with the local ophthalmologist.
References:

1. Mechanism of action of hydroxychloroquine as an antirheumatic drug. Fox RI. Semin Arthritis Rheum 1993;23(2 Suppl 1): 82-91. 2. Rosenthal AR, Kolb H, Bergsma D, Huxsoll D, Hopkins JL, Chloroquine retinopathy in the rhesus monkey. Invest Ophthalmol Vis Sci 1978;17:1158-75. 3. Raines MF, Bhargava SK, Rosen ES. The blood-retinal barrier in chloroquine retinopathy. Invest Ophthalmol Vis Sci 1989;30:1726-31. 4. Yam JCS, Kwok AKH. Ocular toxicity of hydroxychloroquine. Hong Kong Med J. 5. Marmor MF, Carr RE, Easterbrook MD, Farjo AA, Mieler WF. Recommendations on screening for chloroquine and hydroxychloroquine retinopathy. Ophthalmology 2002;109:1377-1382. 6. Levy GD, Munz SJ, Paschal J, Cohen HB, Pince KJ, Peterson T. Incidence of hydroxychloroquine retinopathy in 1207 patients in a large multi-center outpatient practice. Arthritis & Rheumatism 1997; 40(8):1482-6. 7. Mavrikakis I et al. The incidence of irreversible retinal toxicity in patients treated with hydroxychloroquine, a reappraisal. Ophthalmology 2003;110(7):1321-26. 8. Tehrani R, Ostrowski RA, Hariman R, Jay WM. Ocular toxicity of hydroxychloroquine. Seminars in Ophthalmology 2008;23:201-09. 9. Mackenzie AH, Dose refinements in long term therapy of rheumatoid arthritis with antimalarials. Am J Med 1983; 75(1A):40-5. 10. Threshold Amsler grid as a screening tool for asymptomatic patients on hydroxychloroquine therapy. Almony A et al. Br J Ophthalmol 2005;89:569-574. The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009 11. Lee AG. Hydroxychloroquine screening. Br J Ophthalmol2005;89:521-2. 12. Lai TYY, Chan WM, Lai RYK, Lam DSC. Multifocal electroretinographic changes in patients receiving hydroxychloroquine therapy. Am J Ophthalmol 2005;140(5):794-807. 13. Marmor MF. The dilemma of hydroxychloroquine screening: new information from the multifocal ERG. Am J Ophthalmol 2005;140(5):894-5. 14. Kellner U, Renner AB, Tillack H. Fundus autofluorescence and mfERG for early detection of retinal alterations in patients using chloroquine / hydroxychloroquine. Invest Ophthalmol Vis Sci 2006;47(8):3531-8. 15. Silman A, Shipley M. Ophthalmological monitoring for hydroxychloroquine toxicity: a scientific review of available data. Br J Rheumatol 1997;36:599-601.

Reviewing Group
Dr Brian Bourke, the British Society for Rheumatology
Dr Stephen Jones, for and on behalf of the Therapy & Guidelines Subcommittee of the
British Association of Dermatologists.
Mr Arul K Rajammal, Eye Department, Buckinghamshire Hospitals NHS Trust.
Prof Alan Silman, ARC Epidemiology Research Unit, University of Manchester, UK.
Mr Richard Smith, the Royal College of Ophthalmologists (Chair).
Conflicts of interest
None declared.
Amsler Grids (black-on-white or red-on-black) are available in tear-off pads from Keeler
Limited, Clewer Hill Road, Windsor, SL4 4AA. Phone +44 1753 857177.
www.keeler.co.uk

The Royal College of Ophthalmologists
2009


The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009 Appendix 1.
Reading Chart
READING CHART

Use the texts below to test each eye separately with glasses when appropriate. Record the smallest text
that can be read at a distance most comfortable to the patient
He moved forward a few steps: the house was so dark behind him, the world so dim and uncertain in front of him, that for a moment his heart failed him. He might have to search the whole garden for the dog. The camp stood where, until quite lately, had been pasture and ploughland; the farm house still stood in a fold of the hill and had served us for battalion offices; ivy still supported part of what had once been the walls of a fruit garden; And another image came to me, of an arctic hut and a trapper alone with his furs and oil lamp and log fire; the remains of supper on the table, a few books, skis in the corner; Available from Keeler Limited, Clewer Hill Road, Windsor, SL4 4AA. +44 1753 857177 www.keeler.co.uk The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009 Appendix 2
Information for patients taking hydroxychloroquine

Hydroxychloroquine is used to treat a number of conditions which cause inflammation of
the skin, joints or soft tissues. It has been used in a very large number of people since
the 1960s and has a very good safety record.
It can very occasionally cause problems with the vision, which usually take the form of
small areas of reduced vision or distortion near the centre of the vision. This is a very
rare side effect of the drug, but where it has occurred, the effects have usually been
permanent. It is extremely rare for a problem with the vision to occur in people who
have been taking hydroxychloroquine for less than 5 years.
If you suspect that hydroxychloroquine is starting to cause problems with your vision,
you should first of all ask for advice from the doctor who is treating you with the drug. It
may be necessary to stop hydroxychloroquine, but you may need to start an alternative
treatment to prevent the condition for which you are being treated from flaring up. You
should also consult an optometrist (optician) who will be able to check that there is not
another explanation for the problems you have noticed with your vision. The optician
may recommend that you see an ophthalmologist (eye doctor) if further tests are
required.
You can monitor your vision yourself at home. Any problems caused by
hydroxychloroquine may be apparent when you read newspaper print – for instance by
causing patches of print near the print you are actually reading to go missing.
You may be issued with a special chart called an Amsler Chart with which to test your
vision. The Amsler Chart is a grid of squares with a dot at the centre printed on a piece
of paper. You should hold this at a comfortable reading distance (about 30cm or 1 foot)
and view it with your reading glasses (if you wear any), testing one eye at a time. You
should look steadily at the dot in the centre of the chart. When you do this, if the
squares around the central dot appear even with no patches missing, all is well. You
should test each eye about once every month.
If you notice a change in your vision using either of these tests, you should repeat the
test a few days later and if there is still a problem, report it to the doctor who is treating
the condition for which you are taking hydroxychloroquine and arrange a sight test with
your optician.
Remember, it is very unlikely that you will experience an eye problem with
hydroxychloroquine and even if you do experience an eye problem while you are taking
it, it is much more likely that there will be another explanation for it.
The Royal College of Ophthalmologists - Hydroxychloroquine and Ocular Toxicity Recommendations on Screening – October 2009

Source: http://nicholas-lee.com/library/86/RCOPhth%20Hydroxychloroquine.pdf