I dag dykker vi ned i øjets anatomi og hvordan synet egentlig virker.

1: Hvordan synet virker

2: Hvad er langsynet / kortsynet

3: Grå stær

4: Laser Eye Surgery

5: Nat linser

6: Elektrisk omformning af øjet

7: Guld i Øjet

8: Chip i øjet

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1: Hvordan synet virker

Hjerne / Synet forbindelse

https://videnskab.dk/krop-sundhed/oejet-kigger-men-hjernen-ser/

2: Hvad er langsynet / kortsynet

Øjets form

3: Grå stær

Hvad er det?

4: Laser Eye Surgery

LASIK

For those who want do do away with corrective lenses, the main option is LASIK (Laser-Assisted In Situ Keratomileusis) surgery, which uses a laser to reshape the cornea by removing microscopic amounts of tissue beneath a thin flap, allowing light to focus properly on the retina. While, for those suitable for treatment, LASIK has a high success rate – around 95% of patients go on to ditch their glasses only a few days after recovering from surgery – it’s expensive and invasive, and cutting into the cornea alters the structural integrity of the eye.
“LASIK is just a fancy way of doing traditional surgery,” said lead researcher and presenter Michael Hill, a professor in chemistry at Occidental College. “It’s still carving tissue – it’s just carving with a laser.”

5: Nat linser

https://www.city-optik-muenchen.de/en/orthokeratologie-muenchen-ortho-k-nachtlinsen/

Orthokeratology, or Ortho-K, offers a revolutionary way to correct vision without the need for glasses or daytime contacts. By wearing special contact lenses overnight, users can reshape the cornea and experience clear vision throughout the day. This method challenges the conventional approach to eyesight correction, offering a non-invasive alternative for those seeking freedom from corrective lenses.

The cornea is the transparent part of the eye on which the contact lens is placed. It consists of five layers of different thicknesses. However, only the uppermost layer, the so-called epithelium, is important for us.

Corneal epithelium

Bowman membrane

stroma

Descement’s membrane

endothelium

The corneal epithelium is about 0.04mm to 0.06mm thick. It is the uppermost layer of the cornea and renews itself completely once in 7 days. Such an epithelium as it occurs on the eye, there is similarly also on the “normal” skin on the human body. Such an epithelium scales itself off and is thus a protection for the underlying tissue. The Ortho-K contact lens makes use of this process by pushing the top layer of the epithelium from the middle of the cornea (directly above the pupil) to the edge by adhesive forces (tensile forces). Since only the top layer of the epithelium is moved here, the natural protective mechanism of the eye is fully preserved. In addition, this effect of orthokeratology is reversible due to the rapid regeneration time of the epithelium. This means that if the contact lens is no longer worn, it will take another 7 days for the old shortsightedness to be restored. Orthokeratology is in no way harmful to the eye compared to laser eye surgery, which destroys tissue in much deeper layers (stroma) in order to achieve a lasting effect. Recent studies from the USA, on the other hand, have even pointed out that the eye dioptres in orthokeratological contact lenses remain very constant, i.e. do not change. For this reason, Ortho-K contact lenses are also used with children who are already very shortsighted at a young age. In general, there is no age limit for orthokeratology.

6: Elektrisk omformning af øjet

https://bli.uci.edu/laser-free-vision-correction-uses-electrical-current-to-reshape-eye/

Electric Eye Treatment (EMR - electromechanical reshaping)

Denne teknik er stadigvæk ikke godkendt til mennesker, men de er i gang med kliniske forsøg.

Scientists have developed a novel, non-invasive technique that reshapes the cornea using only a mild electric current and a temporary pH shift.

The cornea is the clear, dome-shaped surface at the front of the eye, acting as a transparent window that helps focus incoming light. It’s made of tightly packed collagen fibers and is designed to be strong and smooth. When light enters the eye, the cornea is the first lens it hits – and it’s here that most of light-bending (refraction) occurs in order to focus the light onto the retina at the rear of the eye. However, if the cornea has an irregular curve, it results in conditions such as nearsightedness (myopia) and farsightedness (hyperopia).

What Hill and colleagues propose is instead working with the composition of the cornea to reshape the dome without removing any material from it.

Made primarily of collagen, the cornea maintains its shape thanks to the arrangement of charged molecules and proteins. The researchers discovered that by applying a low-level electrical current through a specially designed platinum “contact lens” electrode, they could change the pH of the tissue, increasing the acidity of the corneal tissue, which would make it pliable just long enough to reshape – like fitting something into a mold. In this case, the mold is the platinum lens.

Then, once the current stops and the pH returns to normal, the cornea hardens again and holds its mold-fitted shape. The whole process takes about a minute, requires no cutting or removal of tissue, and, so far, has shown no structural damage or cell death in the tested samples.

7: Guld i Øjet

https://www.sciencealert.com/gold-injections-in-the-eye-may-be-the-future-of-vision-preservation

The macula is responsible for the central, high-resolution, color vision that is possible in good light. This kind of vision is impaired if the macula is damaged, as in macular degeneration (AMD).

AMD: Sygdommen ødelægger de celler i nethinden, der opfanger lys, og gør det svært at se skarpt. 20-30 procent af befolkningen over 70 år får denne sygdom.

Biomedical engineer Jiarui Nie, from Brown University in Rhode ...