We all want good glasses. It’s about our vision, one of the most important senses. Our eyewear certainly tells a lot about fashion, personality, and status, but one should never forget that glasses also correct visual inaccuracies. In the simplest case, the lens system of the eye is not focusing the light rays on the retina and hence single focal lens correction is needed. It is clearly important that the lens focal point should be positioned in front of the pupils. This is why the most important measure of the optical industry is PD (Pupillary DistancePupillary distance:
The distance between the center of the pupils. Also known as PD.). Measuring PD, however, raises several hard-to-answer questions. How accurately do we need to measure PD? Why do we say that PD (the horizontal fitting height) is so much more important than the fitting height (the vertical PD)? Is PD constant when the focusing distance is constant? In this blog, we will do our bests to answer these questions with experiments designed by engineers and researchers.
In theory, if one has two glasses with the same correction parameters, then changing these glasses should not cause any discomfort to the wearer. However, this is a very rare case. In most cases, if you change your glasses, takes some time for your eyes to adapt. Why is this so?
We are engineers and researchers with several years around the optical industry. It’s a bit like in the Sting song “An Englishman in NY.”. And as an engineer you can’t help but wonder about the protocols of the optical industry. This is even more so, if you talk not only about PD, but also other measures needed for fitting customized progressive lenses. It is far from being clear how accurately vertex distance, wrap angle or pantoscopic angle need to be measured to have a significant impact on lens quality. Till what extent can one repeat the same head pose twice, and what change does this imply in the lens lookout points? We will design scientific experiments to get the best answers possible to these questions.
In the blog, we will also keep an eye on the optical measurements from the industry’s point of view. We will examine the quality of eyewear bought from independent opticians, optical chains or online. When should an optician be definitely consulted, and when is purchasing online just fine in the sense of producing the same eyewear quality from the optical measurement’s point of view?
We also have plans to touch upon cultural differences in the eyewear industry. Why is the Japanese optical market so much different than that of the EU, UK or the US? We will examine the main development trends of these markets and try to find the core reasons for differences.
Our blog is sponsored by mirameasure.com. We promise that this sponsorship will not mean any bias in our experiments. We will publish all details of the experiments, and invite everybody to repeat and share their results, thoughts and comments in our comments section. We encourage discussions, and believe that the content of this blog will be useful for many in the optical industry, and hopefully sometimes also to interested customers. We will try to keep the posts short and informative, and share the measurement details in separate sections.
We will do our bests to come up with interesting topics, design experiments with scientific rigor and publish all our findings. Enjoy, discuss and challenge!