Brief Answer:
Degenerative myopia.

Detailed Answer:
Hi,
Thanks for posting query on this forum,

The macula is the part of the retina responsible for clear vision in your direct line of sight.Macular degeneration is mostly related to a combination of heredity and environmental factors.Over time tissue in your macula may become thin and break down causing complete loss of vision in the effected eye.Unfortunately Macular degeneration can't be cured. However steps can be taken to help slow its progression, such as taking vitamin supplements, eating healthfully.Apart from that she is having Myopic degeneration,It is a condition characterized by progressive stretching of the eye that damages the retina, the layer of light-sensitive cells that lines the back of the eye.Retinal detachment and macular degenration is because of Myopic degeneration.

Treatment
Anti-VEGF therapy using intra-ocular injections of Ranibizumab can be tried to prevent progression of disease.

Advice
As the girl is severely myopic also.

In case of further query feel free to ask follow up question.

Thanks

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