Reza Ferreira Optometrists Menlyn Retail Park,Pretoria
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| Telephone : +27 12 361 0693 |
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| Telephone : +27 12 361 0695 |
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| Cell : 083 984 0785 |
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| Fax : 086 617 1947 |
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| Email : pta@reza.co.za |
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| Website : www.reza.co.za |
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| Physical Address |
Shop 64-66, Menlyn Retail Park
Cnr Lois & Garsfontein, Menlyn Retail Park - Pretoria, Gauteng |
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| Postal Address |
P.O.Box 234,
Menlyn
0063 |
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 Where We Are
1. When driving on the N1 take either the Garsfontein- or Atterbury off-ramps EAST.
2. We are at Menlyn Retail Park opposite the Menlyn Shopping centre.
3. We have FREE parking, right infront of our practice!!!
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 COMMON EYE PROBLEM
As the most common cause of vision loss among people over the age of 60, macular degeneration impacts millions of older adults every year. The disease affects central vision and can sometimes make it difficult to read, drive or perform other activities requiring fine, detailed vision
short sightedness can be overcome by wearing glasses.
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 THE EYE IN DETAIL
1. Vitreous humour
This fluid preserves the spherical shape of our eyeball, as well as helping to support the retina. Despite having the consistency of egg white it is mainly made of water (99%).
2. Ciliary body
The ciliary body comprises two parts – the ciliary process and the ciliary muscle. It is the latter which causes the lens to change shape. If the eye is focusing on a distant object the muscles relax, causing the ligaments to tighten and the lens to lengthen. When we focus on an object nearby the muscles tighten, the ligaments slacken, and the lens shortens.
The lining of the ciliary body also secretes aqueous humour, the fluid which fills the front of the eye.
3. Lens
The lens is responsible for refracting light. Held in place by ligaments, which connect to the ciliary body, the lens can also change shape to focus on objects at different distances – a reflex known as accommodation. It does this approximately 100,000 times a day.
4. Cornea
Although normally only half a millimetre thick, the cornea is responsible for seventy percent of the total focusing of the eye. It is the most important layer in the refractive procedure and, together with the lens, forms a clear image on the back of the retina.
5. Conjunctiva
The conjunctiva is merely a thin, transparent membrane covering the cornea, and yet its function is vital – it protects the eye from airborne debris. This is actually only one of the protective features of the human eye. Others include the orbit (or eye socket), the eyelashes and, quite surprisingly, the eyebrows – their function being to stop sweat from running into the eye.
Tears, which constantly bathe the surface of the eye, also remove dust and dirt – as well as killing bacteria.
6. Aqueous humour
The watery liquid at the front of the eye, secreted mainly by the ciliary body.
7. Iris
The iris is a thin diaphragm that lies behind - and is visible through - the cornea. The iris contains the pupil, which dilates and constricts to regulate the light that reaches the retina.
8. Choroid
The choroid runs behind the retina and, at the front of the eye, forms the ciliary body. As it contains many blood cells, the choroid supplies the eye with nutrients and oxygen – as well as removing waste.
The choroid also has a high concentration of a pigment called melanin in its cells. It is this pigment that prevents internal reflection within the eye – stopping us from receiving a blurred image.
9. Retina
The back of the retina contains a deep layer of light sensitive cells called rods and cones. This is where the image is projected. Rods are responsible for night vision, while cones are responsible for daytime vision. The cones also allow us to see in colour and detail.
The retina also contains a layer of ganglion cells on the surface. These cells connect the nerve fibres to the optic nerve. This means that the nerve fibres actually pass over the sensitive part of the eye, but, odd as it may seem, no disturbance in vision is caused.
10. Sclera
Basically, this is the white of the eye. Attached to the sclera are six exterior muscles, which enable us to look left, right, up and down. At the front of the eye, the sclera forms the cornea.
11. Optic nerve
The optic nerve is responsible for carrying information about the image to the brain. It contains no sensory receptors itself, and therefore therefore the head of the optic nerve (otherwise known as the Optic Disc) corresponds to the normal blind spot of the eye.
12. Fovea
This area of the retina is packed with cone cells. Because of this, it gives the most acute vision. For example, when we are reading, the word on which we are focusing is being projected onto the fovea.
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 HOW WE SEE
The images we see are made up of light reflected from the objects we look at. This light enters the eye through the cornea. Because this part of the eye is curved, it bends the light, creating an upside-down image on the retina (this is eventually put the right way up by the brain).
What happens when light reaches the retina?
The retina is a complex part of the eye, but only the very back of it is light-sensitive. This part of the retina has roughly the area of a 10p coin, and is packed with photosensitive cells called rods and cones. These allow us to see images in colour and detail, and to see at night.
Cones are the cells responsible for daylight vision. There are three kinds - each responding to a different wavelength of light: red, green and blue. The cones allow us to see in colour and detail.
Rods are responsible for night vision. They are sensitive to light but not to colour. In darkness, the cones do not function at all.
Focusing the image
The lens focuses the image. It can do this because it is adjustable - using muscles to change shape and help us focus on objects at different distances. The automatic focusing of the lens is a reflex response and is not controlled by the brain.
Sending the image to the brain
Once the image is clearly focused on the sensitive part of the retina, energy in the light that makes up that image creates an electrical signal. Nerve impulses can then carry information about that image to the brain through the optic nerve.
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