Although spectacles have become much cooler lately, many people still find wearing glass “uncool”, especially the ones who are prescribed ‘corrective’ lenses by an ophthalmologist. Having to constantly wear glasses can be very annoying!
How Does Human Vision Work?
When we look at any object, light from that object strikes the lenses of the eye and an image of the object is formed on the retina, a screen-like object present inside the eye. This image is sent to the brain through the optic nerve (which connects our eyes to the brain) and the brain perceives the object as it appears in reality. This is essentially how human vision works.
Some Details on the Cornea
The cornea plays a vital role in many aspects of human vision. Primarily, it helps to shield the rest of the eye from germs, dust, and other harmful materials.
Not only this, but the cornea also acts as the eye’s outermost lens. It functions like a window that controls and focuses the entry of light into the eye. The cornea contributes between 65-75% of the eye’s total focusing power.
Although the cornea copes very well with minor injuries and abrasions, deeper scratches can cause corneal scarring, resulting in a haze that can ultimately lead to a serious impairment of vision.
Other than that, excessive strain or aging are some of the other factors that diminish the efficiency of the eye’s lenses.
How Do Cornea-reshaping Lenses Work?
The inability to focus on objects that are placed at a particular distance (near-sightedness or far-sightedness) is often caused due to the cornea being in an inappropriate shape. As the name suggests, cornea-reshaping lenses quite simply reshape the lens and temporarily bring it back to its proper shape. This process, known as corneal refractive therapy, is deemed particularly suitable for people with mild myopia, i.e., near sightedness. However, it is also used to treat patients with hypermetropia (far-sightedness) and astigmatism.
This lens has to be worn, just like regular contact lenses, when one goes to sleep at night (at a time when the eye is presumed to be shut for a long period of time) and taken out in the morning. Due to the external support, the cornea adjusts its shape into the mold overnight. Due to this readjustment of the cornea, the person regains normal vision for a day (for some people, it lasts for a few days). The same process can be repeated every day and the process is completely painless.
Because the restoration of vision is only temporary, it is quite unlikely that it would have any adverse effects on the eye. This process not only temporarily restores proper vision in adults, but can also be used to delay the onset of myopia in children.
The surface of the eye is measured by a corneal topographer, which takes precise measurements so that a perfectly-fitting lens can be made. In some cases, the restoration of vision is not perfect (20/20), but the aim of this technology is to provide vision of at least 20/40, which is an acceptable limit for driving a vehicle.
Day-to-day treatment of the eyes without any pain is rather remarkable, and something that can help millions of people see the world a bit more clearly!
- Orthokeratology – Wikipedia
- Science Daily
- Accelerated Orthokeratology – College of Optometry University of Missouri-St. Louis