Blue vision

  My daughter is 13 years old, vivacious and healthy.
  On May 16, she was playing with some friends in a park. The day
  was hot and humid. She was rolling down a gentle slope.
  All of a sudden, she complained of dizziness. We took
  her to level ground. There she complained of a headache in the
  back of her head. She saw two of everything, and she perceived
  all colors in terms of blue and black only.
  We took her to the Emergency Room of our county hospital.
  The doctors found no evidence of external damage.
  A catscan did not reveal internal damage either. The
  headache, dizziness and double vision disappeared within
  a few hours. She was released the next day.
  Since then, her vision is normal -- except that she perceives
  all colors as shades of blue; for example: white looks like
  very pale blue, while red looks like navy blue to her. An
  ophthalmologist pronounced her eyes to be just fine, except
  for a slight myopia which she has had for a few years.
  Our local neurologist ordered EEG and MRI/MRA tests.  The
  tests all look fine, but he did not come up with any diagnosis.
  He opined that it could be a migraine. As her condition did not
  change for over two months, even in response to nortriptylene, we
  thought that the diagnosis of migraine was probably incorrect.
  Then we went to see an endocrinologist, who did not have a clue
  as to what it could be (in fact, he asked us why we went to
  see him), and a neuro-ophthalmologist.  After a very thorough
  examination (the visit lasted 2 hours), the neuro-ophthalmologist
  suggested that the blue vision could be a result of my daughter
  getting very scared when she was rolling down the hill and suddenly
  felt so sick.
  Searching through the web, I found references to
  "cerebral achromatopsia". Whereas "congenital achromatopsia"
  seems to be extensively discussed on the web, "cerebral
  achromatopsia" isn't. I have found information on "blue
  cone monochromacy", dyschromatopsia, chromatopsia, etc.
  However, they seem to have other serious visual disturbances
  (and this was made fairly clear in the PBS special "The
  Island of the Colorblind" with Oliver Sacks),
  while my daughter only suffers from "blue vision".
  Would you be able to provide us some pointers? Is
  our daughter's condition reversible? How do we find a
  specialist doctor who can treat her?
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Thanks for your question.  Cerebral achromatopsia is a disturbance of
colour perception which may be complete or partial.  Usually it is a
consequence of lesions in the so-called "extra-striate" visual cortex.
Most reported cases in the medical literature are associated with a
structural lesion (either infarct or hemorrhage to the extra-striate cortex).
The lack of any lesion as indicated by MRI scans leads to the conclusion of
functional impairment.  There are specific psychophysical tests that can
"map out" the exact range of color deficits, but it does not appear to be
of common clinical usage.  The following are a few articles published in
scientific journals about this topic.  They were not intended and are not
written in layman's terms, but you can find them in any good university
library:
Insights into the different exploits of colour in the visual cortex.
Proc R Soc Lond B Biol Sci 1994 Dec 22;258(1353):327-34   (ISSN: 0962-8452)
A century of cerebral achromatopsia.
Brain 1990 Dec;113 ( Pt 6):1721-77   (ISSN: 0006-8950)
Achromatopsia in the aura of migraine.
J Neurol Neurosurg Psychiatry 1993 Jun;56(6):708-9   (ISSN: 0022-3050)

It is difficult to predict the recovery for your daughter's symptoms,
because the explanation for the symptoms are lacking.  If you would like
another medical opinion, I would suggest a referral to a neuro-ophthalmologist
at a major academic/hospital center.
I hope this information is helpful.
This information is provided for general medical education purposes only.
Please consult your doctor regarding diagnostic and treatment options.