Dec 2003 - Age 3 weeks
First visit with Paediatric Ophthalmologist, confirmed definite diagnosis of
Oculocutaneous Albinism (suspected OCA1A type, formerly called Tyrosinase Negative)
with classic indications of symptoms - foveal
hypoplasia, nystagmus, photophobia as well as optic nerve hypoplasia.
No obvious refractive errors other than normal infant long-sightedness. Predicted
visual impairment likely to be severe, eventual visual acuity expected to be
'legally blind' (6/60 or less) but vision will still be improving in first year/s.
Sept 2004 - Age 9 months
Visual Acuity Test with Teller Cards. Result of 6/141
(about 20/470). Alana is using what vision she has very well.
March 2005 - Age 16 months
Visual Acuity Test with Teller Cards. Result of 6/114
(about 20/380). Alana's functional vision is developing beautifully, she has
very mild short-sightedness (-0.25) and no astigmatism at this stage, so no
requirement for glasses. She has no major dominance of one eye over the other
(very mild strabismus but no signs of amblyopia). The visibility of blood vessels
under region of the macula confirms OCA1A is still the most likely type of albinism
she has. (OCA1A was confirmed by genetic testing in December 2005).
January 2006 - Age 2
years 2 months
Visual Acuity Test with symbol cards (Alana is has enough language skills to
name pictures). Result of 3/60 (equates to about 6/120 or 20/400). Alana's functional
vision is excellent, she still has very mild short-sightedness (-0.25 myopia
or slightly less) and basically no astigmatism, so still no requirement for
glasses. Exotropic strabismus is stable and nystagmus is too. No surgery expected
for some time yet.
July 2006 - Age 2 years
8 months
Visual Acuity Test with symbol cards, result of 3/36 (equates to about 6/72
or 20/240). Right eye scored slightly stronger than the left in acuity. Nystagmus
and left eye's exotropic strabismus is stable, possibly slightly improved at
close range. Refractive errors to be assessed at next examination. Functional
vision is excellent.
May 2007 - Age 3 years
5 months
Visual Acuity Test with symbol cards, result of 3/60 (equates to about 6/120
or 20/400). Right eye has slightly better acuity but utilising a null point
in her left eye damps her nystagmus enough for it to score equally to the right
eye. No change in nystagmus (except for her use of her left eye null point to
great effect) and exotropic strabismus is stable. Refractive errors still negligible.
Functional vision is excellent.
May 2007 - Age 4 years
5 months
Visual Acuity Test with alphabet 'matching' cards, result of 3/60 (equates to
about 6/120 or 20/400). Appears to have no stereopsis (depth perception) at
all according to testing. Right eye still has slightly better acuity but utilising
a null point in her left eye damps her nystagmus enough for it to score equally
to the right eye. No change in nystagmus (except for her use of her left eye
null point to great effect) and exotropic strabismus is stable. Alana now has
some significant astigmatism in both eyes but while we assume it is corneal
astigmatism it may be lenticular or both as this was not determined at this
visit - we don't know the degree of astigmatism either, as her usual P.O. was
not there. It was decided to wait another 6 months for further evaluation of
her astigmatism and refractive error (which we will do with her usual P.O. out
of the public system!!) Functional vision is excellent.
Next visit due October
2008 - Age 4 years 11 months
Teller cards are what's used in the preferential looking test. It's a large card with grating stripes on one side and a blank side on the other. The cards are held at a distance of 55cm in front of the child and the child is observed to see which side they look to. The theory being that a child will "prefer" to look at the striped side, rather than a blank side. The stripes get progressively smaller and once the child has no longer a preference, the previous cards acuity is recorded. There are so many variables to this test that it is considered only a gross estimation of vision and can overestimate or underestimate a child's acuity.