How are cataracts treated GCSE?

Cataracts can be treated by removing the lens and replacing with a plastic lens.

How does the eye work GCSE?

Light passes through the eyeball to the retina. There are two main types of light receptors – rods and cones. Rods are more sensitive to light than cones so they are useful for seeing in dim light. There are three different types of cone cells which produce colour vision.

How does the eye focus GCSE?

Accommodation is the process of changing the shape of the lens to focus on near or distant objects. To focus on a near object – the lens becomes thicker, this allows the light rays to refract (bend) more strongly.

How do contact lenses work GCSE biology?

Contact lenses – work by being in ‘contact’ with your eye. They float on the surface of the cornea. They work like spectacle lenses, by focusing and refracting the light. Laser surgery – reshapes the cornea surgically.

How does the theory of laser eye surgery work?

In other words, it too behaves like a mild lens at the front of your eye. So the theory behind laser eye surgery is to change the shape of the cornea, very slightly, to compensate for problems in the lens behind it.

When to have laser surgery for vision problems?

Laser Surgery Can Improve Vision Problems. Presbyopia or aging eye. The eye loses its ability to change focus because of the natural aging process. This often occurs between ages 40 and 50. Refractive surgery can’t correct this problem. It can make distance vision clearer. But it may make near vision worse.

How does laser eye surgery work to correct short sightedness?

The surgeon then lifts this corneal flap back on a hinge and uses the laser to sculpt the bed of the cornea, fixing any irregularity present. LASIK can flatten the cornea to correct short-sightedness, make it steeper for long-sightedness, and create better symmetry to correct astigmatism.

Which is the most common method of laser eye surgery?

The most popular method of which is LASIK, a procedure carried out on more than 90 percent of Laser Eye Surgery patients. To carry out LASIK, a device called a microkeratome is used to create an incredibly thin flap in the epithelium (the skin of the cornea), about a tenth of a millimetre thick.

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