How the Technology We See With has Changed

We perhaps take it for granted that despite having been born with less than perfect vision, we can continue to have it corrected by lenses, or more permanently elect to have it corrected by laser eye surgery. This was not always the case. This article will explore how technology has changed in optometry.

Early Lenses

13th century examples exist from Europe of handheld convex lenses that were used in the treatment of presbyopia, or vision loss that was age-related. Today, these are referred to as reading glasses. In Italy, lenses were glass-blown and set in in leather, wood, or animal horn. The glass would be held against the face or perched upon the nose.

It is thought that Salvino D’Armate is likely to have invented eyeglasses in about 1285, although there are sources suggesting it was earlier. Salvino was to share his invention with Italian Monk, Allesandro dell Spina. He was the one who made it public, and due to this, has often been crediting with having invented them himself.

Lorgnettes, that is spectacles on a handle, were thought to have been invented by George Adams around 1770.

In 1784, Benjamin Franklin, an American statesman, inventor, and author, was credited with the invention of the bifocal eye lens, which has become invaluable for those having trouble with both long and short distance vision. In 1827, John Isaac Hawkins was to develop trifocals, recognising those people struggling with all distances. A later development would take away the lines which made it obvious that they were bifocal or trifocal lenses.

Pince-nez, a style of glasses not supported by the ears, became popular in the late to early 20th centuries. It is thought that no spectacles had sides until the second quarter of the 18th century when it became the norm.

In the 1980s, safety was introduced for spectacle wearers when plastic lenses were produced. These would be lighter and harder to break, and as technology progressed, ever thinner and more cosmetically pleasing. This material allowed then for protective coatings to be created for lenses which helped reduce the glare from lights and computer screens.

When too much blue light is being emitted from such devices and screens, it can irritate our eyes, as well as having the potential to disrupt our sleeping patterns too. Hence why so many people are now making the decision to wear blue light glasses, or computer glasses, from somewhere like Felix Gray to act as a filter against this type of light, protecting our eye health in the long run. This wouldn’t have been possible without the creation of plastic lenses and protective coatings.

Representing sunglasses for the spectacle wearer, transitions, or photochromic lenses, were first manufactured in 1990 by Transitions Optical, a company in the US. These allowed for a regular pair of glasses to change from clear to dark when outdoors in the sun, and then back to clear once indoors again. As technology developed, this transition period became quicker and different shades could be chosen between.

Contact Lenses

It was possibly German glassblower Muller, using Herschel’s ideas, who came up with contact lenses. Other reports say it was Adolf E. Fick and Paris Optician Edouard Kalt, who first created and fitted contact lenses in 1888 to correct vision problems.

Contact lenses were first developed for more widespread use in the 1970s. They were made from oxygen-permeable materials and known as rigid glass permeable lenses (RGPs). Rigid lenses would be shaped to naturally cover the cornea with a refracting surface created.

A further technological development has been to create softer and disposable lenses. Soflens were the first of the soft contact lenses to be FDA approved in the US in 1971, to then be supplied from 1972. It was not until 1995 that disposable contact lenses were available. The first of these was the Premier Award lens created in Scotland by Roy Hamilton.

Contact lenses are particularly useful in occupations and hobbies where the wearer’s glasses or spectacles might be damaged. For instance, when playing sport. Then, a cosmetic use for them was thought of – they could be used to change the colour of a person’s eyes. This development came about in 1981 with the invention of coloured contact lenses, which were created by the Ciba Vision Company. This had become possible to produce different colours following the development of the soft lenses during the period 1975 to 1980.

Laser Eye Surgery

Since 1988, when the first vision correction/photorefractive keratectomy (PRK) procedure happened, to correct Marguerite McDonald’s damaged eye, laser correction surgery has become widespread for those seeing the wearing of spectacles as less than flattering, and finding it more comfortable, easier, and safer in their job, to not have to wear something on their face.

Going to a centre like Clarity SMILE for surgery is recommended for hyperopia (farsightedness), myopia (nearsightedness), or astigmatism, but less so for presbyopia (age-related farsightedness).

LASIK has been FDA-approved in the US since 1999. In most cases, patients electing to have the surgery will end up with 20/20 vision.

So, we can now, if we choose to, see without feeling self-conscious or having the bother of fitting contact lenses in a morning.


Ancient Star Explosions Revealed in Deep-Sea Sediments

A mystery surrounding the space around our cosmic region is unfolding thanks to evidence of supernovae found in deep-sea sediments. According to a scientific study which shows the Earth has been travelling for the 33,000 years through a cloud of faintly radioactive dust. The study suggests that these clouds could be remnants of previous supernova explosions, a powerful and super bright explosion of a start.

Researchers searched through several deep-sea sediments from two different locations that date back to 33,000 years using an extremely sensitive instrument called a spectrometer. They found clear traces of the isotope iron-60, which is formed when starts die in supernova explosions.

Iron-60 is radioactive and completely decays away within 15 million years, which means any iron-60 found on Earth must have been formed much later than the rest of the 4.6 billion year old earth and appeared here from nearby supernovae before settling on the bottom of the sea.

Scientists have discovered traces of iron-60 at about 2.6 million years ago, and maybe another at approximately 6 million years ago, suggesting earth had traversed fallout clouds from nearby supernovae. For the last few thousand years the solar system has been moving through a heavy cloud of gas and dust, known as the local interstellar cloud (LIC), whose origins are unclear.

If this cloud had originated during the previous few million years from a supernova, it probably would consist of iron-60, and so the team of researchers decided to search more recent sediments to find out. Turns out, there was iron-60 in the sediment at remarkably low levels – equating to radioactive levels in space far below Earth’s natural background levels – and the distribution of the iron-60 matched earth’s recent travel through the local interstellar cloud. But the iron-60 reached further back and was spread throughout all the 33,000-year measurement period.

The lack of correlation with the solar system’s time in the current local interstellar cloud seems to bring more questions than answers. Firstly, if the cloud was not formed by a supernova where did it come from? Some have theorised that it came from aggressive chemical reactions from distant galaxies that ended up travelling at the speed of light in all directions during the big bang. But there is no definitive evidence to support this kind of claim currently.

But secondly, why is there iron-60 so evenly spread out throughout space? A few scientists have suggested that iron-60 is a key element in the forming of a wide range of planets throughout the universe and it go there through a massive chain of gravitational pulls from different entities with high levels of mass throughout space to explain its even distribution. This is currently speculation at best, but it could provide inspiration for future research methodologies.

Other scientists say there are recent papers that suggest iron-60 trapped in dust particles might bounce around in the interstellar medium, so the iron-60 could originate from even older supernovae explosions, and what we measure is some kind of echo. One thing is for certain though, more data is required to resolve some of mysteries.

There could be potentially so many more secrets about our universe hidden in the depths of our deepest oceans. That might become more of a research focal point for astrophysicists as they attempt to uncover the origins of our universe. Even though it can sometimes feel like we are close to a unifying answer, when more research is done, more questions arise. This is only natural when attempting to quantify the extremely large and extremely small solar system mysteries.