Artificial Eyes 2

Vision Loss

Vision loss refers to a broad spectrum of visual impairment, which includes a reduction in the ability to see clearly. It can range from mild to sever and may involve issues like blurred vision decreased peripheral vision, and difficulty in focusing

Blindness

Blindness, on the other hand, is the complete loss or absence of vision. An individual who is blind has little to no light perception and cannot see objects or shapes

Examples of Optical Low Vision Aids

Correctly refracted glasses, magnifying spectacles, magnifiers and telescopes for low vision

Examples of Non-Optical Devices

• Watches with audible announcements

• Large-print text

• Audible books

• Large-sized numbers and high-contrast colors

• Textured labels

Age-related Macular Degeneration (AMD)

• With AMD you lose your central vision. You cannot see fine details, whether you are looking at something close or far

• But your peripheral (side) vision will still be normal.

• It is a leading cause of vision loss in people 50 years or older

What are two types of inherited retinal degenerations

Juvenile Macular Dystrophy

Retinitis Pigmentosa

Retina Pigmentosa

• Trouble seeing at night

• Decreasing peripheral vision (tunnel vision)

What is the issue of the retina research

The retina is incredibly sophisticated, and regrowing is not possible

Why does vision prostheses used?

In severe vision loss arising from degenerative retinal disease

What are the two main retinal diseases for vision prostheses

• Inherited retinal degenerations such as retinitis pigmentosa, RP

• Age-related degenerative disease such as atrophic age-related macular degeneration, AMD

What does RP and AMD do to the eye

In these conditions, the photoreceptors (rods and cones) in the outer layers of the retina are damaged or lost, but the inner retinal neurons (bipolar and ganglion cells) remain relatively intact

What could an implant device do RP and AMD

The implant devices can wake up and excite the remaining parts of the visual pathway to bring back some basic vision for the people who use them

What are the challenges with implant devices

• Challenges: Transmitting signals between artificial implants and the bodys natural components

• Technology Miniaturization: Electronics have become smaller, but their architecture remains unchanged

• Nature’s Blueprint: Our body’s wiring follows a fractal pattern, offering efficient communication. The curvature of eye makes the process more complicated

• Research Imperative: Achieving seamless communication requires multidisciplinary and complex research efforts.

What happens if you apply to a large voltage to the eyeball

If you apply a large voltage to the eyeball, that signal will go into the eye, shoot down the optic nerve to the brain, so you can see.

What happens when stimulating the back of the brain

He showed that stimulating the back of the brain produced still, centred flashes of light (phosphenes), while stimulating the other areas produced peripheral phosphenes, validating the retinocortical map.

What happened when examining the minimum number of light points required to enable the reading of printed text by recipients

Visual field map of phosphenes generated by the implant. Numbers refer to the electrode being stimulated. Note that some phosphenes are elongated, and some multiple (with curly braces) phosphenes appear when a single electrode is stimulated.

First retinal prosthesis

He reported on the implantation of an electrode array in back of the eye of a blind volunteer.-

Patient Response: - Blind volunteer's post-operative perception: "uniform white light"

What can be expected when with a retinal implant

Could be greyscale, could be blurry or need to be reconstructed

What is the overall system overview of artificial etes

external power, image sensor →Processing → Stimulation electronics → electrodes → retinal