This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Retina, Subject name: Ophthalmology
Argus 2 implants have been experimentally tried in: 
Select and explain. 
A. Failed penetrating keratoplasty, B. Retinitis pigmentosa, C. Advanced Glaucoma, D. Optic atrophy
B: Retinitis pigmentosa
Answer: B: Retinitis pigmentosa 
Explanation: Argus 2 retinal implants have been tried in Retinitis pigmentosa patients. Treatment modalities for Retinitis Pigmentosa Crisp Car technique Low vision aids Bionic eye Argus 2 retinal implant High dose vitamin A are the modalities tested