What is a Prescription
A prescription is the numerical result of your eye exam as written by an optometrist and specifies the value of all parameters the prescriber has deemed necessary to construct corrective lenses appropriate for the patient.
If an examination indicates that corrective lenses are appropriate, the prescriber generally provides the patient with an eyewear prescription at the conclusion of the exam.
To have the most accurate possible prescription and to abide to the General Optical Council, we require a prescription that is under two years old. We recommend that if your prescription is older than this to please make sure you have a sight examination for up-to-date prescription results.
We also need prescription information from the following patients:
- Aged between 16-59 years old
- Under 1 years old
- 60 years old or Over
- Diabetic or have a strong family history of glaucoma.
A prescription can be given to you if you suffer from long-sightedness or short-sightedness.
Long-sightedness, also known as farsightedness or Hyperopia, means that the eyes' focus is "behind" or "too long". which makes it difficult to see objects close up rather than from a distance. This occurs when light from objects viewed will theoretically focus behind the retina rather than on it. However, because the eye is able to naturally fatten the lens and cause light to bend more, this error in focus is overcome. This explains why distance vision is usually good. When the same individual tries to look at something up close, much more effort is required, as light from a near object will fall much further back behind the retina. Near vision is therefore worse.
Short-sightedness, also known as nearsightedness or Myopia, means that the light focuses in front of your retina or 'too short.' This makes it difficult to see objects in the distance whereas objects close up are clearer. This occurs when light from the objects seen focuses in front of the retina rather than on it. This is believed to happen when the eyeball is slightly too long, and is also known as Axial Myopia.
Having 20/20 vision is how we explain perfect vision where a prescription is not required to see clearly and comfortably. The fraction 20/20 is understood as follows: the bottom half of the fraction represents the distance, in feet, at which a perfectly sighted person is able to see a target seen by another perfectly sighted person at 20 feet. However, if you have trouble seeing things in the distance, you might see at 20 feet what a perfectly sighted person sees at 40 feet. So, this means that your vision is measured as 20/40.
Assuming you have perfect sight when you are looking at an object in the distance, light from the object will focus on your retina very precisely. When seeing an object close up, the focus is blurred very momentarily, but this is unnoticeable, because your eye has an automatic refocusing ability that makes the target clear. This refocusing ability is called "accommodation" and works by making the natural lens of the eye larger or more convex in shape. As we get older, we lose more and more of this ability, which is why things close up start to blur after about 45 years of age.