How to Read Your Glasses Prescription?

What is a glasses prescription?

A glasses prescription is a written or printed copy of the refractive error of your eyes that’s issued by your optometrist after an eye exam. The optician then dispenses and supplies the glasses based on the given prescription.

The Malaysian Context

As far as I’m concerned, a lot of practices in Malaysia don’t usually issue glasses prescription to their patients after an ‘eye exam’. I deliberately put the words (eye exam) in quotation marks because a lot of eye exams you come across are not really an eye exam in their own right. They are really just a refraction test in most cases to determine your refractive error like short-sightedness without the means to examine your eye health.

Refraction alone ≠ eye exam/test

Worst still, I’d personally come across optical practices in the country that were willing to supply prescription glasses to me based on the ESTIMATED prescription from an auto-refractor. The whole ‘refraction process’ lasted for less than 2 minutes. Therefore, Malaysians are probably more familiar with the printout of their prescription from an auto-refractor than a proper prescription copy issued by an optometrist.


Breaking down a sample prescription

Nonetheless, proper practices that provide comprehensive eye exams will issue a prescription copy to you after an eye test. And these practices run by qualified and registered optometrists as well as opticians DO exist in the country. Although they may look different in their appearance, a glasses prescription comprises 3 main components, namely:

  • SPH (sphere)This shows if you are short-sighted or long-sighted
  • CYL (cylinder)This shows the degree of your astigmatism
  • AX (axis)This will only exist if you have astigmatism and it shows the orientation of your astigmatism

prescription copy that details the spherical and cylindrical power as well as the axis of the glasses

Extra components

Sometimes a glasses prescription contains some other elements like:

  • NEAR-ADD (near addition) 
  • INTER-ADD (intermediate addition)
  • Prism 
  • Base
  • PD (pupillary distance)


Near-addition is the ‘extra power’ on top of the spherical power for people with presbyopia to carry out near work like reading. This ‘extra power’ compensates for the loss of elasticity of the natural lens in a presbyope as part of the normal ageing process.

On some occasions, you will come across an ‘inter-add’ component which is similar to near addition. However, it functions to enable presbyopes to see clearly in an intermediate distance (eg. looking at computer).

prism Is used to correct binocular problems like squint
Prism is sometimes useful to ‘correct’ squint

Prism, on the other hand, allows people with binocular problems (eg.squint) to see clearly just one image (prevent double vision). Besides, PD, which is short for pupillary distance, is the distance between your pupils. A dispensing optician is responsible for measuring the PD as part of the dispensing process. This measurement is important because it allows an optician to fit your glasses PROPERLY especially for people with high prescription.

Conclusion – The importance of glasses prescription

There’s a shortage of optometrists in Malaysia even until to date. However, with more and more optometry graduates, it’s just a matter of time before the country finally sees itself with enough optometrists to serve a population of 3 million. As of now, we are still fairly far behind the 1:8000 optometrists to population ratio as seen in most developed countries.

As a result, other eye care practitioners like opticians and ophthalmologists are required to fill the gap. Besides, there are simply no adequate regulations in place to uphold the standards of optometry in the country. For instance, one can simply buy glasses without a proper prescription copy or have an eye exam done before.

However, things will eventually fall into place. Malaysians will find themselves needing a proper glasses prescription as proof of having a comprehensive eye exam done (or it’s still up-to-date) before they can even buy glasses or contact lenses. This is a means to safeguard the eye health of the public rather than inconveniencing them.

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