macular dystrophy\stargardt: what can be done?

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John H. - 30 Oct 2007 11:49 GMT

Can someone help me understand this:

Does dim light increase the vision cycle activity and therefore raise the
risk of increased rate of damage in macular dystrophy or stargardt?

Is it advisable for an 11 year old girl just diagnosed with either(they are
not sure of exact condition) to wear sunglasses and minimise light exposure?

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Dr Judy - 30 Oct 2007 16:48 GMT

> Can someone help me understand this:
>
> Does dim light increase the vision cycle activity and therefore raise the
> risk of increased rate of damage in macular dystrophy or stargardt?

Some experiments with mice with genetic mutations similar to
Stargardt's found progression of the disease was slower if the mice
were raised in dim light or in total darkness. Whether this would
also be true of humans is not yet known. People with Stargardt's have
abnormally slow vision cycles, whether this is a cause or a result of
retinal degeneration is unknown.

PubMed citations: 14709597, 15067110 use http://www.ncbi.nlm.nih.gov/sites/entrez?db=PubMed
to find them.

> Is it advisable for an 11 year old girl just diagnosed with either(they are
> not sure of exact condition) to wear sunglasses and minimise light exposure?

Based on the mouse studies, some are recommending that people with
Stargardt's use brimmed hats and sunglasses while outdoors. As
Stargardt's does cause light sensitivity, the patient will at least be
more comfortable with sunglasses even if progression of the disease is
not slowed.

http://www.lighthouse.org/medical/eye-disorders/stargardts-disease/

Dr Judy

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John H. - 31 Oct 2007 02:25 GMT

Thanks Dr. Judy,

I had advised light protection but wanted to be sure. Found the link
below last night during my own searching. Vision cycle is slowed
because the problem appears to relate directly to vision cycle
dysfunction. There is even some evidence to suggest that reducing
vitamin A intake can help because the culprit appears to be a
transporter of the same to the RPE fails, vit A builds up, undergoes
changes, becomes toxic and the rest if tragic. There is a mouse model
for the same but the genetics is confounding, as usual unlikely to be
single gene.

Sadly there are no clinical trials but there is some evidence to
suggest that interventions of a lifestyle and dietary change will
alleviate disease progression. However no false hope here, only
minimal modulation.

Oh and I'll start an argument. I have also suggested "palming" because
by reducing retinal activity, even for a few minutes every hour, may
help limit toxic aggregation and give the "house keeping" functions
some hope of reducing the same. Essentially the same logic as reducing
light exposure.

John.

> > Can someone help me understand this:
>
[quoted text clipped - 23 lines]
>
> Dr Judy

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John H. - 04 Nov 2007 06:42 GMT

By the way Dr. Judy, it has become to my attention that naturopaths often
prescribe high doses of vitamin A for juvenile macular degeneration. This is
exactly the opposite of what should be done and there is also some evidence
to suggest that in adult AMD high levels of beta carotene are ill advised.

> > Can someone help me understand this:
> >
[quoted text clipped - 23 lines]
>
> Dr Judy

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