Long-sightedness

Health encyclopaedia - Alphabetical Topic List

| A |

| B |

| C |

| D |

| E |

| F |

| G |

| H |

| I |

| J |

| K |

| L |

| M |

| N |

| O |

| P |

| Q |

| R |

| S |

| T |

| U |

| V |

| W |

| X |

| Y |

Hypermetropia is a sight problem that affects your ability to see close-up objects. Commonly known as long-sightedness, the condition is a type of focussing error, and tends to get worse as you get older.

Sight problems are very common, and many people are either long or short-sighted. Although sight problems sometimes run in families, there are no other significant factors why some of us have better vision than others. Long-sightedness can be easily corrected with glasses, contact lenses, or corrective surgery.

How does the eye work?

The eye is made up of three parts:

the cornea and lens, which focus light at the front of the eye,
the retina, a light sensitive film at the back of the eye, and
the optic nerves- a large collection of communication wires to the brain.

The eye works by focussing light rays on the retina. These rays of light first travel through the transparent cornea, and then through the lens, which helps to focus the light. The image that forms on the retina is transformed into electrical signals, which the nerves carry to the brain so that it can tell us what we are seeing.

Long-sightedness occurs when the eyeball is too short in relation to the focusing power of the cornea and lens. This means that light rays travel to the back of the retina before they have been bent by the cornea and lens. Close-up objects therefore appear blurry because the light rays have not been focussed properly. Long-sighted children often find it easy to see distant objects clearly, because the lens is flexible in young eyes and able to focus easily. As you get older, it becomes more difficult to focus, and the way that you see distant objects may also be affected.