December 2017


THE EFFECTS OF ALCOHOL ON THE EYES

As 2017 draws to a close, we would like to take this opportunity to wish you and your families a joyful, peaceful and safe festive season, and all the best for the coming year. Frequently called the "silly season", for good reason, the end of the year brings with it many occasions to celebrate, spend time with family and friends, and sometimes indulge in excessive consumption of alcohol. Moderate drinking may lead to some changes in vision, but these are usually short-term. Heavy drinking over an extended period of time often impacts the body and the eyes in a more serious way, and the effects can be more permanent.

Short-term visual effects

Consuming alcohol in moderation is unlikely to have any lasting adverse effects on the eyes, and the symptoms usually disappear shortly after a drinking episode. The way the body responds to alcohol differs from one person to another. The way your body responds depends on the amount consumed and your tolerance threshold.

Alcohol slows the pace of communication between neurotransmitters in the brain. Neurotransmitters are chemical messengers that communicate information around the brain and to the body. The delay in communication between the brain and the eyes affects eye muscle coordination. This may result in distorted or double vision, difficulty with depth perception, difficulty judging distances, and decreased peripheral vision. It makes perfect sense, then, not to drink and drive!

Excessive drinking decreases the reaction time of the pupils, which are unable to constrict or dilate effectively when reacting to ambient light levels and allowing appropriate levels of light into the eyes. This impairs the ability to see contrasting colours and different shades of similar colours, as well as reducing visual sharpness.

Alcohol is a diuretic, leading to dehydration in the body and the eyes. Even a small amount of alcohol can worsen the symptoms of people who suffer from dry eyes, and cause dry irritated eyes and headaches in those who are not sufferers. The symptoms will disappear once the hydration levels of the body return to normal, but it may be useful to have hydrating eye drops or artificial tears on hand when drinking. Alternating alcoholic drinks with water will minimise the dehydrating effects of alcohol.

A typical sign of alcohol consumption is bloodshot or red eyes, which is caused by the dilation or swelling of the blood vessels of the eyes, making them appear more prominent.

Twitching of the eyelids can be triggered by alcohol consumption.

Long-term visual effects

The weakness of the eye muscles can become permanent over time, resulting in involuntary rapid eye movements.

Long-term excessive alcohol use can lead to toxic amblyopia, a permanent loss of vision due to the direct effect of alcohol on the optic nerve which transmits visual images from the eyes to the brain.

The risks of developing cataracts and age-related macular degeneration are increased with the long-term excessive consumption of alcohol.

Certain vitamins and minerals are needed to maintain eye health and healthy vision. The absorption of these essential nutrients by the body is impaired by the excessive use of alcohol. Vitamin A helps protect the surface of the eyes, and the lack of vitamin A can cause night blindness, thinning of the cornea, eye dryness and retinal damage. Vitamin C is an antioxidant which helps support the blood vessels of the eyes, while vitamin E plays a role in protecting the eyes against age-related conditions. Inadequate levels of these vitamins can have a long-term detrimental effect on vision and eye health.


I CAN SEE CLEARLY NOW!
(THE TREES HAVE LEAVES!)

"I think its time for this cataract to be removed." This observation by my optometrist did not come as a surprise! I had known for some time that I had cataracts in both eyes, and that the one in my right eye was considerably worse than the left one, but they were not posing any problems. YET!! Over the past year or so I had begun to notice changes in my right eye. My vision had deteriorated dramatically, to the point that I was unable to read the print on the TV screen, and my optometrist had to change my contact lens script every few months. Night driving had become increasingly difficult, the headlights of oncoming cars too bright, and haloes appearing around street lights and other lights. My left eye could compensate to some extent for activities such as reading and computer work, but distance vision had become a strain, even when I was wearing glasses or contact lenses. Reluctant as I was to have eye surgery, I was forced to agree with my optometrist that the time had come to make an appointment with an ophthalmic surgeon.

Doctors have their individual styles, protocols and procedures for running their practices, and this was my specific experience with my particular ophthalmic surgeon, which may not be the same for another one. After taking a detailed health, family and vision history, she conducted a comprehensive eye examination. She started with a visual acuity test to measure the clarity of my vision with each eye. I am shortsighted, so my vision was not clear without my contact lenses, but my right eye was worse with and without the contact lenses, due to the cataract. A test of the pressure inside my eyes was done.

Using a slit lamp, the surgeon examined the structures of my eyes under magnification, looking for any problems in the cornea, lens and iris. To determine peripheral vision, a visual field assessment was done. In order to see the retina at the back of my eye clearly, the ophthalmologist needed to dilate my pupils by putting drops in my eyes. Apart from the dense cataract in my right eye (as well as the beginnings of one in the left), all was well, and the doctor calculated the measurements for the intraocular lens she would implant in my eye to replace the lens that would be removed. A date was set for the cataract surgery.

A week before surgery, I needed to collect forms from the ophthalmologist's receptionist. These included a consent form for the surgery which needed to be read and signed, a quote detailing the codes required by my medical aid so that I could obtain authorisation, the hospital admission form which I took to the hospital a few days before the surgery, the anaesthetic form with questions regarding my general health, and a prescription for eye drops to be used before and after the surgery. These detailed instructions giving me information about the procedures to be followed helped to lessen my anxiety.

Most people I had spoken to about cataract surgery commented on how easy and uneventful the experience had been. In spite of this, on the day of surgery, I arrived at the day clinic feeling quite nervous. My blood pressure and temperature were taken, and I changed into the hospital gown. Drops were inserted into my eye at regular intervals to dilate the pupil in preparation for the surgery. The anaesthetist came by to introduce herself, and explain that I would be awake but sedated during surgery. A short while later I was wheeled into the waiting area of the theatre, and was then taken into what looked like a laboratory, where the ophthalmologist examined my eyes, checked that the pupil was dilated, and confirmed the measurements of the intraocular lens. Then into the theatre. Once the microscope had been positioned and the sheet draped over me, I felt the prick of the needle in my arm as the sedation was administered. I don't remember much of what happened during the surgery, which I am told took about 40 minutes. All I remember clearly is being wheeled back to the ward and having a patch over my right eye.

Having not had anything to eat or drink since 10.00p.m. the previous night, all I wanted was a cup of tea. In the ward there was a tray of breakfast, including a pot of tea. The eye patch affected my vision, and the first thing I did was to knock over the jug of milk! By the calm manner in which the nurse dealt with it, I thought she had probably dealt with this situation before! I had my tea, got dressed, and was home half an hour later, feeling absolutely fine. The only discomfort was the disorientating sensation of the eye patch.

The next morning the ophthalmologist removed the patch, examined my eye and assessed my visual acuity. The vision in my right eye was 20/20. We were both delighted! With instructions to continue inserting the drops and to return a week later, I left the doctor's room feeling on top of the world. Being shortsighted for as long as I can remember, I have never been able to see clearly without glasses or contact lenses. In fact, when I received my first pair of glasses at age 11, I looked out of the window and commented to my mother that I didn't know people could see individual leaves on trees from that distance. After my cataract surgery, my daughter's first question was: "Do the trees have leaves, mom?"


HOW ACCURATELY DO WE SEE OURSELVES?

The camera never lies. Or does it? Does the camera give a more accurate view of ourselves than a mirror does? Or is the image we see in the mirror a truer reflection of what we really look like? Does the image we have of ourselves match the way other people see us? We assume that the camera records exactly what our eyes see, but the truth is that, although there are some similarities, the camera and the eyes "see" differently. Both the camera and the human eye process light and record images, but the brain interprets and makes sense of what is seen.

Human Eye vs Camera

As with a camera, light enters the eye through the front part of the eye, the cornea, is focused by the lens, and passes through the eye until it reaches the retina at the back of the eye. The pupil and the iris act like the aperture in a camera lens, opening and closing depending on the amount of light reaching the eye and the amount of clarity needed. The retina contains two types of light-sensitive receptors, rods and cones. Rods perceive light while cones are sensitive to colour. Once the eye captures an image, it is sent via the optic nerve to the brain, where the processing happens. Unlike the camera, which snaps a picture and that's it, our eyes receive a continuous flow of images, which the brain later processes into what we actually see.

The eyes "look" while the brain "sees". The brain uses the image from the retina and other stimuli to create an image of which only a small percentage is based on actual eyesight. The rest is generated from the environment, our previous knowledge, past experiences, and expectations. Essentially, our eyesight is a dynamic complex process in which the brain uses a combination of stimuli and information from different sources to finally generate what we see and to make sense of the world around us. While the camera records what is out there, the eye selects the object of greatest interest, often not even registering other objects nearby.

Basically, the camera works very much like the human eye. It uses the lens to focus light onto the sensor, where it is transformed into electrical impulses which are later processed and translated into usable images. Unlike the eye, which is capable of perceiving millions of colours, the camera is not sensitive to colour. In order to be able to produce colour images, the sensor needs a filter array on top of it which will filter out the wavelengths of certain colours. The camera is simply a tool for capturing images, as it lacks the processing power and ability of the brain.

The eyes have a limited spectrum of light that they can capture from a given light source. The camera, which is capable of doing longer exposures, can gather much more light and pack it into one picture, representing the scene much more clearly and brightly than our eyes could. This is especially noticeable when photographing the stars since the human eye would never be able to capture the colours and contrasts as the camera is able to do.

Trust the Mirror

The general belief may be that the camera never lies, but in fact the mirror is more reliable than the camera. By its nature, the camera has to transform a 3D real life image into a 2D photograph, and consequently distorts the image by altering the proportions to some extent. This has a role to play in the fact that some people are more photogenic than others; the angles, features and proportions determine that certain faces photograph better than others.

When looking in the mirror we are seeing a face in motion rather than a static image reflected in a photograph. The still image makes small flaws more noticeable and seem more prominent than they would if one was looking at a face in a natural dynamic way.

A mirror image is literally an image in reverse. A camera picks up the opposite of the image we see when looking in the mirror. No face is perfectly symmetrical, and we get so used to seeing a mirrored version of ourselves that when we see a photograph which is even slightly different from what we are used to we subconsciously notice the tiny differences and think we don't look right. Most people prefer the image of themselves in the mirror to the one in a photograph.

With a mirror, all you can see is you, so you can ‘pose' or change your expression so that you look your best in your own opinion. With a photo, you're sometimes caught in poses that may not suit you, or, if there are other people in the photo, you may compare yourself with them, and that will alter your view of how good you think you look.

The truth is that we don't really know what we look like. The image we have of ourselves is not exactly how other people see us, or of how the camera captures us. Most importantly, in the wise words of well-known author Dr Seuss:


WHILE WE WEREN'T LOOKING

What a year it's been, huh? A rollercoaster in every sense of the word. There were sanctions and nuclear threats and discussions about refugees. Paris celebrated its victory at being awarded the 2024 Olympics, while we mourned the news that we won't be hosting a certain World Cup.

But you know what? A lot of things went almost unnoticed while we had our eyes fixed on Brexit and an orange president who doesn't know when to stop tweeting. (Not to mention another president who threw in the towel after 37 years.)

While all this was happening, most of us didn't even notice that other pretty amazing things were happening. While we had our eyes on Twitter and Trump, others used their eyes to make some incredible discoveries.

Such as... a new species of orangutan was discovered in Indonesia this year. They say it was the first new ape species to be discovered in over a century. I don't know how they found it, but there it is.

And if the discovery of a new orangutan is something special, how about the discovery of a whole new continent?! Yup, a new continent (which is mostly underwater) was discovered this year in the South Pacific. It's called Zealandia, and word is it'll soon be officially recognised as earth's eighth continent. So while we had our eyes on an assortment of Kardashians, someone was busy discovering a whole new land mass.

And we all heard about the total solar eclipse in 2017. But did we know it was also the year of the first observed collision of two neutron stars? (Okay, I have no idea what that means but it sounds like a big deal. I mean, I'm always impressed with firsts and this sounds like a good one...)

Archaeologists in Western Australia discovered the world's largest dinosaur footprint, clocking in at 1.7 metres. Meanwhile, the Cassiopeia jellyfish was discovered to be the first brainless animal that sleeps. (I don't know exactly how they knew it was sleeping, but kind of a big deal anyway, right?)

A jellyfish isn't the kind of thing that makes headlines, especially when British princes are getting engaged. But isn't it great to know that someone out there is keeping their eyes peeled for new kinds of jellyfish and orangutans and who knows what else?

So there you go. It wasn't just a year of terror and nuclear. While we had our eyes on the shocking headlines, other people were using their eyes to discover amazing things. On that note, happy holidays and Happy New Year. Let's see what we can see in 2018.

By the way, please remember to get your eyes checked. Otherwise you might pull a Warren Beatty/Faye Dunaway and read out the wrong winner on Oscar night. And hey, no one wants to be the biggest scandal of the year.