Ancient Lenses
Roman Emperor Nero viewed the fights of his gladiators through a natural magnifier – which was made out of Emerald. He lived from December 27 AD to June 68 AD and was the Roman Emperor for twelve years. Archaeologists have found ancient lens-shaped pieces of glass, but they were not ground to what we know of today as optical quality. Most ancient lenses were convex shape, which is shaped like a pillow shape, with the thickest part in the middle and thin on the edges. This means that close objects could be enlarged, so were probably used for writing. The lenses focus the light to a spot, and this intense spot of heat could be used for other things – not just sight. They could also have been used to light fires and possible treating wounds via cautery. There is no evidence at this time that any lenses were mounted or worn as eye-glasses.
It is believed that glasses were invented in 1268-1289 in Italy. The earliest glasses were made from crystal. People held them in front of the eye as they were so heavy! Unfortunately natural crystal is not a uniform structure, so there would have been blurry areas within the lens. They soon manufactured glass to a better standard. The early glass lenses created a lot of chromatic aberrations, causing the person to see a blurry rainbow out the edges of the lens. In 1730 Chester More Hall used two lenses fused together – one of ‘old crown glass’ and the other of a newer ‘flint glass’. This corrected the issue of chromatic aberration, which lead to a high demand of glasses from the mid-1700s onwards.
Knowledge from the old days
There are many things our grandmother told us that still hold true. For example using a gold wedding ring to treat a stye. We know now that styes are caused by a block oil duct on the eyelid rim. Rubbing a gold wedding ring on the eye was thought to ease it. Now we suggest a hot compress, as the heat liquefies the oil – and we know that rubbing continuously with the ring would have generated heat. Nowadays we also say to use massage to help clear out the blockage, which would have been helped by rubbing. Interestingly gold is a natural anti-bacterial which would have also helped the eye to heal.
I also read recently about an ‘eye surgeon’ from the 16th century. A lot of these so called eye doctors at this time started off their career as a barber and medical treatment was a side-line to them. Cupping and bloodletting were some of the common procedures they would undertake. Interestingly the white and red striped poles you see even now in the barbershop come from the day when they would be drying their blood-filled bandages out to dry.
Georg Bartsich (1535-1607) used to travel to fairs to help treat people. He fashioned his own equipment – like a spoon to scoop an eyeball from its socket. He would only perform surgeries by the wax and wane of the moon and was guided by the signs of the zodiac. He developed a particular interest in eyes and published a book on the topic. I found it interesting to read why he thought cataracts developed:
From the albumin arising from the brain which thickens
From the blood mixed with too much evil humour
An impure stomach, liver or spleen
Irregular and course foods
Excessive crying
From injuries
In 2017 we know the most common cause of cataracts is age. In the world, it is the leading cause of blindness – but in New Zealand we have great surgeons who are able to help us out long before blindness sets in. I find it interesting to think about the past and what little knowledge they had about the eyes and it makes me even more grateful for the care we can provide people to help them look after their eyesight.
Melissa Hay, Visique Optometrists, 155 Kitchener Road, Milford 09 489 4797 milford@visique.co.nz
