Feasibility Study of a Chronic Retinal Stimulator in Retinitis Pigmentosa

The chronic retinal stimulation system is an implantable electronic device designed to
provide electrical stimulation of the retina in order to elicit visual percepts in blind
subjects.

This chronic feasibility study will evaluate the ability of subjects to resolve multiple
percepts and patterns under various stimulus conditions and optimize the effectiveness of
electrical stimulus parameters with an initial chronic design.

Inclusion Criteria:

- Confirmed history of retinal degenerative disease in the worse seeing eye with
remaining vision no better than light perception. The fellow eye can have any visual
acuity but must have better vision than the eye that will have the surgery.

- History of former useful form vision in worse-seeing eye

- Acceptable ability to describe visual percepts

- Age eighteen (18) or older

Exclusion Criteria:

- History of glaucoma

- Optic neuropathy or other confirmed damage to optic nerve or visual cortical damage

- Presence of communicable disease/infection

- Pregnancy

- History of claustrophobia

- Inconsistent flash detection thresholds

- Any other diseases that can effect the function of the retina

- Subjects with a Beck Depression Inventory Interpretation score of >30 and subsequent
diagnosis of depression by a psychiatrist.

- Corneal degeneration