Refractive surgery encompasses a collection of operations designed to correct focusing errors of the eye. There are a number of such errors including:
- Myopia (Shortsightedness)
- Hyperopia (Longsightedness)
- Astigmatism (Uneven bending of light rays)
1. Myopia (shortsightedness)
Myopia or shortsightedness is a condition in which the eye can see close objects but has difficulty bringing distant objects into focus.
Myopia is often detected in childhood and typically the condition progresses during the teenage years generally running a 10 – 15 year course but levels off in early adulthood. As a result there may be a need for new glasses every six to twelve months during this period of progression. There is usually very little change in this condition after the early to mid twenties.
Hypermetropia is a condition in which the eye can see distant objects more clearly then close objects. With this condition the rays of light focus behind the eye because the eye is either too short or the cornea too flat. Depending on the degree of severity, people who are longsighted may have reduced near vision and distance vision, but have greatest difficulty with close work.
For normal, undistorted vision, the cornea should be smooth and equally curved in all directions. In an astigmatic eye, the cornea curves more in one direction than the other so that the surface is more like the shape of a football or rugby ball rather than a soccer ball.
Astigmatism distorts or blurs vision for objects at any distance. It is usually evident from an early age and will require some form of vision correction. Low level astigmatism is very common, and may not be bothersome. Astigmatism commonly occurs together with myopia or hypermetropia.
Presbyopia is the effect of the ageing process on your vision. As you age it is not uncommon to experience a gradual difficulty in focusing your eyes for reading or close work. This is a condition that can be easily corrected with reading glasses, but it is normal to require a gradual increase in their strength over the years. It will not bother most people until they are in their mid 40s, an age when the lens gradually starts to lose some of its flexibility.
Bifocal or multifocal lenses may need to be prescribed for people with presbyopia if they also suffer myopia, astigmatism or hypermetropia.
After the laser vision correction procedure you will typically be normally sighted and you will be just like every other normal-sighted person in that, when you reach your mid-forties reading glasses will usually be required. The excimer laser has no effect on your eye's focusing muscles or the lens. As such, the excimer laser cannot directly help patients who are solely experiencing the effects of presbyopia. However, Monovision can be used to help overcome some of the limitations arising from presbyopia.
Monovision is a treatment for presbyopia where one eye may be corrected by laser for reading and the other eye for distance vision, so in effect you use one eye for near sight and the other for distance.
This treatment is not suitable for everyone but we can discuss the details with you and discuss your suitability. Your regular eye care practitioner can provide a contact lens for a trial of Monovision to see if this option suits your lifestyle. A choice for laser vision correction is a lifestyle decision, whether it is for practical, professional, sporting or leisure purposes.