Brief Answer:
Treatment depends on new or old infection.

Detailed Answer:
Hello
Welcome to Health care magic.

I am Dr. Dadapeer K, an ophthalmologist and I will be answering your question.

I reviewed your history and the report attached with the question.
It seems from the history that your sister is having toxoplasmosis. Her report shows IgG levels are increased with normal IgM level.
This indicates that this is chronic or old infection.
Since the vision in the affected eye is less, this indicates a probable toxoplasma scar of the retina.
Treatment is required or can be done in case of active infection.
Hence first thing to be done is to know the stage of the disease whether it is active or inactive.
This can be found out by examination of retina by indirect ophthalmoscopy and fundus photography.
Hence if possible you can send me a fund us photo so that I can assess and answer your question more accurately.

There are quiet a good hospitals in XXXXXXX like XXXXXXX XXXXXXX Eye hospital and you can get consultation there.

Hope the information is helpful to you.

Do write back to me for further questions.

Thank you
With regards

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