Spectacular Spectacles

According to the Vision Council in America, ~74% of adults need an aid to correct their vision, with 64% wearing glasses. I’ve worn glasses since I was 3 and so much has changed in the last 20 years or so. I thought it was time to delve a bit deeper into the world of spectacular spectacles, and what research is doing for the future of vision.

Early this year one of our youngest competition winners, Basma, wrote an article about the amazing human eye. There she explained lots of keys terms and what was what inside our eyes. Light is focused on a part at the back of our eyes, called the retina, a complex layer of cells. The retina reacts to light and conveys this information to the brain for further processing. For those of us who suffer from long (hyperopia) or short sightedness (myopia), we can use corrective glasses or lenses. The reason for such a problem is due to the lens within our eye. For example, I am shortsighted with a prescription of -6.00 and -5.25. This means that without any corrective methods, I cannot see my own hand clearly if it is more than 30cm or so from my face. My lenses focus the light too soon, so I use a minus lens (concave) to correct this and focus the light on my retina. For longsighted people, their lenses do not focus the light soon enough, so they use a plus lens (convex) to correct for this and focus the lights sooner. eyeballconvex_concave.png

Since so many people need corrective vision, technology has improved our experiences with inventions such as contact lenses, bifocal glasses, prescription goggles and even laser eye surgery. However, I’ve always wondered how transition lenses worked. Growing up with glasses, I remember the first adverts for these, watching adults walk out in the sun and their glasses change with no effort. How? These are called photochromic lenses; in poor or low light they look like normal glasses, but in sunlight they darken as sunglasses. Generally speaking sunglasses work in one of two ways: (1) they use a coloured filter to only let through light of a certain colour, and block out the rest, or (2) by polarisation. This lens acts as tiny slits, and only allows light through which is travelling in a certain direction, darkening the image you see. Photochromic lenses however are different again. Organic molecules (naphthopyrans) within the glass react with UV light from the sun, so indoors there is very little UV light as our windows etc., block it out, but outdoors the lenses will react and darken. When UV light hits these chemicals, their structure alters and can now “soak up” more light, darkening the glass.photochromatic.png

Another marvel is anti-glare coatings. It may not sound like much but picture looking at a light and not seeing only the light as one crisp shape but also a spiky glow all around it. Now imagine that only when you’re trying to drive at night with all the street lamps…it’s not pleasant in your glasses, and can be dangerous. This is where anti-glare, or anti-reflective coatings have come in recently. These coatings reduce the glare reflected off your glasses, allowing more light to pass into your eye, giving a sharper and clearer image; this can also help in reducing eye strain. These coatings can allow for up to 99.5% of light to enter your eye, helping you to see with ease. The process of applying anti-glare is quite fiddly. If you want to learn more follow this LINK.

Glasses have been around for a very long time; the science of optics has been known for at least 1000 years! What about current research? The first study using CRISPR (i.e. a gene editing tool. I wrote an article about the CRISPR revolution HERE) inside the human body is about to take place in the US. The study will be using CRISPR to treat a genetic eye disorder which causes blindness, and is a common cause of childhood blindness affecting 2-3 of every 100,000 babies. The condition is due to a defective gene which affects the function of the retina. CRISPR will allow scientists to correct the section of DNA which causes the defect, injecting the treatment into the patient’s retina. There will be 18 patients in the trial, from the age of 3 up to adults. This study differs from the controversial work of the Chinese scientist who edited the DNA of twin embryos, as this CRISPR change cannot be passed down to future generations.Gene editing

The advancements in technology surrounding eye conditions is astonishing, enabling optometrists to image the eyes (including internally) and thus, providing the ability to spot early signs of conditions or potentially cancerous sites. The research using CRISPR could lead to a whole new era of scientific investigation; it’s an exciting time to be working in medicine. (If you want to know all about CRISPR, read my previous article here).

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