![Intraocular lens
• It is a tiny, artificial lens that replaces the natural lens that is replaced
during a cataract surgery
• The most common procedure is Phacoemulsification, creating a small
incision in the cornea through which a probe is used to break the
cloudy lens which is removed by the suction.
• The IOL device is then placed in the intact capsular bag.
[ Cataract is the clouding of lens that occurs due to change in lens
proteins, a natural phenomena that occur during aging.]](https://image.slidesharecdn.com/artificialvisionb33-240605070107-56f45550/85/Artificial-vision-system-developed-in-resent-days-10-320.jpg)
![Corneal onlays and inlays
• Inlays are the implants placed in
the corneal stroma for a
correction of presbyopia.
• For a people with refractive
disorder, a combination
procedure can be done: LASIK
to fix the refractive disorder the
same time inlay is implanted.
[ presbyopia: inability to
focus/accommodate at near
objects. Refractive disorders:
myopia, hypermetropia,
astigmatism]](https://image.slidesharecdn.com/artificialvisionb33-240605070107-56f45550/85/Artificial-vision-system-developed-in-resent-days-12-320.jpg)
![Benefits and drawbacks
• The retinal or optic nerve implants are relatively non invasive, as it
is placed in the eye/optic nerve and it does not require brain surgery.
• The technology has been around sometime and has gone numerous
clinical trials making it relatively well established.
• Better image quality [ retinal < optic nerve < cortical]
• The technology for optic nerve/cortical implants is in early stages of
development and the clinical trial have not yet yielded conclusive
result.
• The cortical implants may require brain surgery which carries more
risks and potential complications.](https://image.slidesharecdn.com/artificialvisionb33-240605070107-56f45550/85/Artificial-vision-system-developed-in-resent-days-28-320.jpg)
Artificial vision system developed in resent days
- 1. Artificial vision Presented by: Susmita Bhagat 7th semester
- 2. Introduction • Organ responsible for vision situated in a bony cavity, called the orbit is connected to the brain via optic pathways • Organ of greater complexity • Easier to observe and access for the surgery • Cataract is the principal cause of blindness in Nepal followed by glaucoma and diabetic retinopathy and trachoma. • Globally also the main cause of blindness or vision impairment are refractive errors, diabetic retinopathy, Cataract, age related macular degeneration.
- 4. • Sclera is white outer coating and protective membrane of the eye • Choroid is the inner nutrients containing membrane • Lens helps to focus light on the retina • Cornea helps to focus light so object looks sharps and clear • Iris is the coloured part and regulates the amount of light entering the eye through pupil( opening at the centre of iris) • Vitreous humor is the clear gel that fills inside of the eye. • Retina is light sensitive and sends electrical impulses to the brain via optic nerve.
- 5. Biomaterials used in ophthalmology
- 6. Ideal properties • Ability to deliver oxygen to tissues, refractive changes, tissue integration and healing • Safe, inert and nontoxic • Gas permeability, hydrophobic surfaces, no water retaining( lenses) • PMMA used in lenses must be rigid, non collapsible and hydrophobic
- 7. Recent development in prostheses vision implant technologies 1. Contact lenses 2. Intraocular lenses 3. Inlays and onlays 4. Artificial tear 5. Vitreous substitutes 6. Bionic eyes 7. Tissue engineering
- 8. Contact lens • Synthetic lens that sits on the surface of eye and corrects the vision problems like myopia, hypermetropia, presbyopia, astigmatism. • Soft contact lens made of a very soft and flexible water absorbing material that confronts to the eye shape, usually disposable and lasting for a day , weeks or a month. • Hard contact lens is made up of rigid gas permeable plastic covering only a part of cornea. • From a material point of view, it depends on mechanical properties, lens thickness, wettability, water content, oxygen permeability and handling cost. Final contact lens requires a consideration of wear time, comfort and cost.
- 10. Intraocular lens • It is a tiny, artificial lens that replaces the natural lens that is replaced during a cataract surgery • The most common procedure is Phacoemulsification, creating a small incision in the cornea through which a probe is used to break the cloudy lens which is removed by the suction. • The IOL device is then placed in the intact capsular bag. [ Cataract is the clouding of lens that occurs due to change in lens proteins, a natural phenomena that occur during aging.]
- 12. Corneal onlays and inlays • Inlays are the implants placed in the corneal stroma for a correction of presbyopia. • For a people with refractive disorder, a combination procedure can be done: LASIK to fix the refractive disorder the same time inlay is implanted. [ presbyopia: inability to focus/accommodate at near objects. Refractive disorders: myopia, hypermetropia, astigmatism]
- 14. Vitreous substitute • It fills the posterior space between the lens and the retina. • It is a clear gel, highly transparent, inhomogeneous, consists of several parts with different densities and composition. • Different Substitutes available today make it possible to replace the mechanical function, but its is toxic in the long run. • Currently, silicon oil is the only substitutes used for long run. • Hydrogels and smart hydrogels are a good candidates as a long term vitreous body. • Researches have been ongoing on the use of cross linked hydrogels and others.
- 15. Properties and mechanism • Nontoxic and biocompatible • Clear and transparent with density and refractive index similar to the natural one. • Buffering agent and hydrophilic • Allow the transfer of proteins, metabolites and solutes. • Non biodegradable and non absorbable
- 17. Bionic Eyes • Bionic eyes also known as visual prostheses are implantable devices that are designed to restore vision to individuals with visual impairments. • These devices come in different types, each targeting a specific area of the visual system. • The three main types are retinal implants, optic nerve implants and cortical implants • Optic nerve implants are designed to restore the vision of individuals with optic nerve damage that may result from glaucoma, optic neuritis and others. • Cortical implants are designed to restore the vision of individuals with damage to visual cortex, a part of the brain that process visual information.
- 18. Retinal implants • They are designed to restore the vision of individuals with retinal degenerative disease. • It helps to replace the function of damaged or destroyed photoreceptor cells in the retina. • These cells convert light into electrical signals that are sent to brain . • These implants work by bypassing the damaged photoreceptor cells and directly stimulating the remaining healthy cells in the retina. • It is the most common type of bionic eye.
- 20. Working mechanism • It works on the principle of using electrical stimulation for producing visual sensation in the brain. • It consists of tiny array of electrodes that are implanted in the retina. • These electrodes are connected to a small camera that is mounted on a pair of glasses worn by a patient. • The camera captures the images and sends it to the computer that processes it and send the signals to the electrode . • The electrode gets stimulated and produces a small current that activates the remaining healthy cells in retina. • These cells send signals to the brain , where they are interpreted as visual images.
- 22. AI in Bionic eye development 1).AI based image processing: • To improve the quality of images captured by bionic eye’s camera. • To enhance the resolution, colour and contrast of the images. Example: Use of adaptive optics to correct the optical aberrations in the eye by using deformable mirrors. It reduces the distortion caused by natural curvature of the eye.
- 23. Contd.. 2) Machine learning algorithms • Improves the performances of bionic eyes by analysing the data generated by the devices and optimizing its functions. • Identify patterns in the data and adjusts the settings to enhance the performances. Example: It can be used to adjusts the stimulation patterns in the parameters in the electrode to optimize the perception in visual images.
- 25. Contd.. 3). Neural networks • To develop more sophisticated bionic eyes that can interpret visual information in a more naturalistic way. • They are trained using images captured by bionic eyes and overtime they can learn to recognize patterns in the electrical signals generated by the electrodes. Example: Artificial retina which can mimic the function of natural retina.
- 27. Advancements In technology • AI based approaches have been used in the design, functioning and commercialization of bionic eye to enhance the performances. • Developments of wireless devices that can be implanted in the eye eliminating the need for external components making the bionic eye more comfortable and convenient for users. • Several clinical trials are currently underway to evaluate the efficacy and safety of bionic eyes. For example: The company named second sight has developed a retinal implant that have been approved for use in USA and Europe.
- 28. Benefits and drawbacks • The retinal or optic nerve implants are relatively non invasive, as it is placed in the eye/optic nerve and it does not require brain surgery. • The technology has been around sometime and has gone numerous clinical trials making it relatively well established. • Better image quality [ retinal < optic nerve < cortical] • The technology for optic nerve/cortical implants is in early stages of development and the clinical trial have not yet yielded conclusive result. • The cortical implants may require brain surgery which carries more risks and potential complications.
- 29. Tissue engineering • It is based on the combination of scaffolds, cells and biologically active molecules to promote the development of functional tissues. • The main goal is to assemble functional constructs that restore, maintain or improve damaged tissues or whole organ. • In the eye, it has been reported mainly in the anterior region( cornea, conjunctiva) and significant progress has been made in cell therapies to treat degenerative disease of the retina. • 3D preformed scaffolds using cells and natural or artificial substrate have been studied and enhances the stem cell based medicine.
- 31. References 1. https://scholar.google.com/scholar?as_ylo=2023&q=ai+in+bionic+e ye&hl=en&as_sdt=0,5#d=gs_qabs&t=1701999968668&u=%23p%3 DZVj3Yj1hsZkJ 2. https://scholar.google.com/scholar?as_ylo=2022&q=biomaterials+f or+ophthalmology&hl=en&as_sdt=0,5#d=gs_qabs&t=17020000498 32&u=%23p%3D0qqyZXH1SZIJ 3. https://scholar.google.com/scholar?q=artificial+vision+supra+choro idal+retinal&hl=en&as_sdt=0,5#d=gs_qabs&t=1702000143069&u= %23p%3D7XAkgr15LiUJ