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Refractive Error

Minor eye disorders are common.  Over half the Australian population uses some form of vision correction, whether it be glasses or contact lenses.  Nearly everyone will require some vision correction at some time during their life and this is due to refractive error.

Refractive error is where the image of the object a person is looking at is not focused properly onto the retina (the light-sensitive tissue in the back of our eyes).  Refractive errors can usually be corrected using spectacles or contact lenses.

 

The most common refractive errors are:

MYOPIA

Myopia, is commonly referred to as short sightedness.  It is a condition in which light is focused in front of the retina, resulting in blurred vision.   For myopia to develop, either the eyeball has to become longer (axial length change) or the power of the eyeball has to become stronger (lens or corneal shape changes).  It is now thought that myopia is caused by both genetic and environment factors.  People with myopia can generally see objects at close distances reasonably clear, but will not be able to see distant objects clearly.

There is currently no cure for myopia, but spectacles, contact lenses and refractive surgery can all provide good distance vision for people with myopia.  Myopia development and progression has become of the most investigated areas in vision research not only because the myopia incidence is growing in the younger generation but because high  egrees of myopia carry higher risk of ocular health conditions such as retinal detachment.

At Coady Davenport, Rebekah has a keen interest in myopia development and therefore myopia control.

 

HYPEROPIA

Hyperopia (long-sightedness) is a condition in which the optical components of the eye are not strong enough, and so light is therefore focused behind the retina resulting in blurred vision that is usually worse at shorter distances such as when reading or on the computer.

People with hyperopia usually have reasonable distance vision, but may find that their vision is blurred at near or they may experience symptoms such as eye strain or headaches when doing near work.  Hyperopia is important to detect in the early years as it may cause a turned eye in children (also known  strabismus).  Hyperopia is also important in the early learning years of school as it makes attending to activities at near (such as reading) more effortful, and if it is too hard, the student may avoid, leading to  learning difficulties.

 

ASTIGMATISM

Astigmatism is blurred vision at all distances caused by the shape of the front surface of the eye (the cornea).  It also can be caused by the slight tilting of the lens inside the eye.  Astigmatism is commonly an inherited characteristic or it can be a normal variation accompanying growth.  Spectacles and contact lenses (both hard and soft) can correct astigmatism.

 

PRESBYOPIA (vision after 40)

Presbyopia is the gradual reduction in the amount that the eye can change its focus.  These changes are a normal part of ageing as the lens inside our eyes lose their flexibility.  Usually these changes become noticeable between the ages of 40 and 50, with the inability to focus on near objects.  People in this age group often start to find they have to hold things further and further away to be able to see them clearly.

Presbyopia can be corrected by an optical prescription specifically designed for close work.  This can ben provided in many forms including reading glasses, occupational lenses, bifocals, trifocals or progressive lenses (multifocals).  There are also contact lenses available to correct presbyopia.