Method and ocular implant for transmission of nerve-stimulation light

Abstract

An improved prosthesis and method for stimulating vision nerves to obtain a vision sensation that is useful for the patient that has lost vision due to age-related macular degeneration (AMD) and retinitis pigmentosa (RP) and other diseases. The present invention utilizes infrared light to cause action potentials in the retinal nerves similar to those which result from rods and cones stimulated by visible light in healthy retinas. In some embodiments, the invention provides a pathway or “image pipe” for transmitting a stimulation pattern of infrared light from an external stimulator array through the eye and focusing the stimulation pattern of infrared light on the retina, especially the fovea. Some embodiments provide improved resolution down to a group of nerves, or even the individual nerve level, with sufficient energy density so as to cause a desired action potential.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of U.S. patent application Ser. No. 13 / 204,610 filed Aug. 5, 2011, titled “Ocular Implant and Method for Transmission of Nerve-Stimulation Light” (to issue as U.S. Pat. No. 8,709,078 on Apr. 29, 2014), which claims priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61 / 514,894 filed Aug. 3, 2011, titled “Sight-Restoring Visual Prosthetic and Method Using Infrared Nerve-Stimulation Light” (Attorney Docket 5032.067PV1), both of which are incorporated herein by reference in their entirety.[0002]This invention is related to the following prior applications and patents:U.S. Provisional Patent Application No. 60 / 715,884 filed Sep. 9, 2005, titled “Apparatus and Method for Optical Stimulation of Nerves” (Attorney Docket 5032.009PV1);U.S. patent application Ser. No. 11 / 257,793 filed Oct. 24, 2005, titled “Apparatus for Optical Stimulation of Nerves and Other Animal Tissue” (now U.S....

AI Technical Summary

Benefits of technology

[0021]The present invention uses infrared nerve stimulation (INS) technology that uses infrared light to cause action potentials in nerve cells in the eye. In recent years, optical-stimulation technology has been developed to stimulate nerves. This INS technology can achieve much higher precision and selectivity of stimulation than using electrical current to trigger nerve action potentials. In some embodiments, the present technology uses pulsed, infrared lasers to excite the neural tissue next to the retina directly and without tissue damage. The advent of this technology represents a paradigm shift in artificial nerve stimulation because it allows a high degree of spatial selectivity of neural stimulation without the need for tissue contact.

[0022]The present invention provides an improved prosthesis and method for stimulating vision nerves to obtain a vision sensation that is useful for the patient that has lost vision due to AMD, RP, and other diseases. The invention utilizes infrared light to cause action potentials in the retinal nerves similar to those action potentials that result from rods and cones stimulated by visible light in healthy retinas. In a related invention by one of the inventors of the present invention, an eyeglass-mounted system is described that collects visual information and converts it into a stimulation pattern which is projected into the eye at an infrared wavelength with the purpose of causing an action potential in the retinal nerves with the purpose of recreating sight. As the infrared light stimulation wavelengths are normally strongly absorbed by the vitreous humor and tissues of the eye, in some embodiments the invention provides a pathway or “image pipe” for transmitting a stimulation pattern of infrared nerve-stimulation light, from an external infrared-light-emitting stimulator array, through the eye and focusing the stimulation pattern of infrared light on the nerves of the retina, especially the macula and fovea. In some embodiments, the invention provides improved resolution down to a group of nerves, or even the individual nerve level, with sufficient energy density so as to cause desired action potentials in the targeted nerves.

[0025]In some embodiments, once surgically implanted in the eye, the ocular implant has no internal moving parts relative to the eyeball and no internal electrical parts. Thus, such an ocular implant requires no internal or external electrical-power source. Additionally, the ocular implant does not impede movement of the eyeball after surgical implantation. In some embodiments, the freedom of eye movement relative to the external stimulator light can help provide enhanced patient comfort and enhanced perceived image resolution.

Problems solved by technology

For many patients suffering from retinal degenerative diseases such as advanced or age-related macular degeneration (AMD) and retinitis pigmentosa (RP) there has been little hope for maintaining vision.

There are presently no cures for these debilitating diseases, and, at best, current treatments only slow the disease progression.

The overall social and economic impact of AMD and RP is immense and the importance of treating blindness is profound as this is a problem of significant scope and breadth.

Advanced macular degeneration and retinitis pigmentosa are both diseases that degrade vision in patients and eventually will lead to blindness.

These devices apply an electric current pulse to stimulate the neurons of the visual system which is inherently hindered by a lack of spatial selectivity.

Electrical current spread leads to imprecise nerve stimulation and limits the ability of the neuroprosthesis to restore function.

The limitation of spatial selectivity is based on fundamental physical principles of electrical stimulation.

The technology is further limited by the fact that physical contact is required with tissue, which can lead to damage over time.

Implantation of a complex powered device in very close proximity to sensitive neural tissue forms a significant drawback to this approach, making it impossible to update the technology without further risky surgeries.

Electrical stimulation represents a major challenge in developing implantable devices with long-term system performance while reducing their overall size.

Since no micro-cables are required to be attached to the device, and its overall form and edges are rounded, the device is not expected to stress the retina during chronic implantation.

Electrical stimulation, as described in the above devices and patents, is limited since the spread of electricity does not allow separate or independent stimulation of individual retinal nerve cells or even small-enough groups of nerve cells.

Electrical stimulation thus greatly limits the number of separately stimulated sites that are possible.

Additionally, the electrical-stimulation approach will require implantation of a powered (e.g., an electrically powered) device, which has significant, difficult issues associated with obtaining power into the eye and using the power by devices in the eye.

This area may have some potential, however it will require significant development work, it involves injecting a virus into nerve tissue (which may have significant side effects and FDA-approval issues), and the virus is only partially taken up by nerve cells.

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