Choroideremia
Choroideremia (CHM) is a slowly progressive, X-linked (heritable) retinal disorder.
The disorder is rare, occurring in 1 in 50,000 individuals in the general population.
Affected males develop night blindness in their early years and gradually lose
peripheral vision which results in legal blindness by age 40.
CHM male
Normal
Normal male
fundus
Right eye
Normal male
Left eye
Fundus of a 9 year old CHM male (left): the pigment layer has a “salt and pepper”
appearance (represented by black arrows) and is more transparent allowing one to
see the deep blood vessels of the choroid (represented by white arrow), compared
to normal fundus (right photograph)
Fundus of right eye of 13 year old CHM male: the retinal pigment epithelial layer
is patchy, probably thinned, and lacking pigment (arrow)
OD
Fundus of 18 year old CHM male: The pigment layer is now very thin and
possibly absent (black arrow) except in the central area called the macula
(white arrow), which remains healthy. The overlying retina remains intact,
but is transparent.
OD
OS
Right eye
Left eye
Fundus of 26 year old CHM male: The sclera (whitish) is visible
with choroidal blood vessels (white arrow) in the areas outside
the central macula (black arrow). The visual field is
compromised with shaded areas not seeing well.
Goldmann Visual Field- Right eye (CHM)
Fundus – Right eye
Goldmann Visual Field- Normal
Retinal findings in Retinitis Pigmentosa
differ from CHM
• The optic nerve is much paler
than in CHM.
• The blood vessels are thinner
than in CHM.
• There are areas of pigment (also
termed bone spicules) in the
retina more commonly in RP
than CHM (arrow).
• The retinal pigment epithelium
under the macula is atrophic in
this case of RP (loss of structure
within the circle).
Female carriers of choroideremia
• In general female carriers experience a milder form
of choroideremia.
• Some carriers experience a decline in visual
function with difficulty seeing at night after age 50.
• In rare cases, female carriers may exhibit severe
symptoms similar to those of affected males.
Female carrier with signs in the eye
Normal
Normal
Right eye
CHM carrier
CHM carrier
2-D scan of the retina of a choroideremia carrier
showing central thinning of the retina (arrow)
Normal retinal image
CHM carrier retinal image
Fundus of female carrier (left) and
autofluorescent image of the same eye (right).
Note areas of speckling of the pigment layer representing
its deterioration (arrow)
Additional Resources
• Choroideremia Research Foundation:
USA: www.choroideremia.org
Canada: www.choroideremia.ca
• Foundation Fighting Blindness:
USA: www.blindness.org
Canada: www.ffb.ca
• Choroideremia patient survey:
English: http://choroideremiasurvey.questionpro.com/
French: http://choroideremieenquete.questionpro.com/
Contact Us
• For questions or comments about this
presentation please contact us at:
stacey.stone@albertahealthservices.ca
• For information regarding care options
appropriate for you and your family, please
contact your ophthalmologist.