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Why Do I Need to “Adjust” to My New Prescription?

It is your annual routine optometry appointment, which involves looking at the prescription of your glasses or your contact lenses. Your optometrist has advised you that there has been a change in your prescription and updating your prescription lenses are recommended. You make your way to your dispensing optician, which provides you with expert lens advice, taking in consideration your lifestyle, your occupation and perhaps your hobbies. Whenever you’ve been advised that there has been a prescription change, it is mentioned that you might need some time to “adjust” to your new prescription. What does this mean? Why is it every time you need to take some time for your eyes to “adjust”?

Understanding “Why” Your Prescription Changes

Whenever your optometrist measures your prescription, we always compare your old prescription with your updated one. There are several factors which may impact changes to your prescription, such as uncontrolled diabetes, advancing cataracts or pregnancy. Your glasses and contact lens prescription also “changes” between different optometrists or practitioners.

This is call inter-practitioner variability. The environment your prescription is taken, the equipment used also could give a “different” reading. This means that if you had your eye exam elsewhere last year, by choosing a different optometry practice and optometrist, your prescription could vary. Similarly, if you use different scales to measure your weight, there could be subtle differences in the readings. By definition, differences in readings, no matter how slight is considered a “change.”

Is a change in prescription warranted?

Suppose you’re monitoring your weight. In the morning, it measures 65.0kg. On the same day in the evening, you measured your weight again, and it measures 65.1kg. Is that considered a change?

In optometry, your optical lenses are measured in power units of 0.25D. Depending on the optometry practice, and the technique of obtaining your optical prescription, you can see your prescription could fluctuate in the order of +/- 0.25D. A general rule of thumb is that each 0.25D variation gives you the ability to read an extra line below on the eye chart. So whilst 0.25D of change in your prescription is small, it cannot be neglected without further investigations and tests during your optometry appointment whether updating your current prescription is beneficial.

Understanding “functional” changes in your prescription

At Capital Eye, we understand during your routine eye tests; it is often that you might make an “incorrect choice.” Double-checking your answers are standard; however, we make the judgement whether we change your current prescription dependant on whether the new prescription would actually make you see better, and with more comfort. This is what we call a change in function.

There is little point in getting new glasses based on a minor change that you won’t notice the improvement in vision throughout your everyday living. Sometimes, a small change in vision could significantly improve your comfort of vision. In this case, the benefits of updating your spectacles will be discussed before we proceed in ordering your lenses.

The Bottom Line

Think about the time you bought shoes or any time of clothing that you wear. You might notice shoes across different brands, and shirts and pants with different styles fit and feel differently when you try them on despite the sizes are the same. It may take a couple of days for you to feel comfortable in your new shoes.

A similar process happens when you pick up the glasses. As long as your vision is clear (the prescription), it may take you a couple of days to feel comfortable wearing the glasses confidently.

This adaptation process is especially important for patients requiring multifocal lenses since there is a vast range of different multifocal lenses you can get on the market with varying quality.

It is unlikely you know the type, the brand of multifocals you were given. Perhaps they didn’t work the first time, and you were told to just put up with it. Being an independent optometry practice, we have access to a broader variety of multifocal lenses that would tailor suit your vision requirements. Whether it is for sports, work or study, our qualified optical dispensers are ready to discuss lens options that are best suited for your needs.