2. Your environment
I wear size 9 shoes. It doesn't matter what day of the week or the time of day, they are always size 9's! My feet might be a bit swollen at the end of the day but I'm still going to wear a size 9.
So what? I hear you cry!
1. Eyetests are subjective
I wear size 9 shoes. Every day of the week and any time of the day - always size 9's! They might feel a bit tight at the end of the day but always size 9's.
"So what?" I hear you ask........
When we test your eyes we measure to a very fine tolerance and the four main elements of a prescription (sphere, cylinder, axis and add) can each be adjusted up and down in the tiniest of steps. The result relies of our skill and experience and your responses to questions like "Is it better with one or two?" or "Is it sharper on red or green?". These questions help us decide which tiny step to choose in each of those 4 main elements of the prescription but you may have noticed how difficult the question appears to be to answer correctly sometimes? That's because we are not asking you to choose between a size 8 or 9 or 10 shoe - we know you are a size 9 by this point but are trying to decide if you are an 8.9, a 9.0 or a 9.1 - difficult decision to call!
If you multiply those 4 main elements of choice out you can easily get to 81 correct answers for someone's prescription. If you go to 10 opticians today for an eyetest, you may well get 10 different 'correct' prescriptions!
Once we have completed a subjective result we then try and test it further based on environment.
4. Managing your expectations
We can refine your prescription based on your visual demands in your world. Do you drive?, Do you read? If you do read, is it books, newspapers, tech devices?, Do you have specific hobbies that require vision correction? How far is your TV from your sofa? etc.
If we understand what your real life is like we can make better judgements on the prescription that best suits those needs.
Before your next appointment, have a think about what areas of your life you have the most visual challenges so that we can maximise how we can help you.
3. Your general health and wellbeing
Illnesses can affect your prescription results. Your eyes have focussing muscles and just like the rest of the body they get tired too. Even a common cold will affect your ability to focus. Do please let us know if you are poorly so that we can best support you visually.
Often it might not be the illness but the medication you are taking. Anti-histamines, pain killers and HRT drugs all might have an affect and there are many more simple over the counter drugs that can affect vision. Complex therapy drugs will have big affects so please always let us know what medications you might be taking and we can advise you accordingly.