Retinitis pigmentosa (RP) affects the photoreceptors in the back of the eye. Specifically, the rods are damaged first, which results in the typical symptom presentation of difficulty seeing in dim lighting and progressive tunnel vision. As the disease progresses and more rods become damaged, it has been theorized that central vision loss occurs when the cones become damaged, and that damage is due to oxidative stress. The cells die because they do not use glucose efficiently. In this study, researchers at Harvard University explore the relationship between RP & cone damage in the hopes that a non-genetic-based treatment can be developed to protect against the later end-stage disease symptoms. The method they were studying is an adeno-associated virus vector that expresses a molecule, "Txnip" that was shown to protect the cones in RP by making the cells better at alternative energy production.
What this means for Usher syndrome: This treatment may help preserve remaining vision. For Usher patients with end-stage disease progression, there is a possibility of retaining central daytime vision, allowing for continued use of visual cues to assist with activities of daily living.