Posts Tagged ‘eyeball’

The Perfect System

Sunday, June 20th, 2010

The eye is one of the most amazing organs in our bodies. Our sight is the most precious of our senses, and these small and perfect globes make sight happen by refracting light through it’s systems to help us make sense of our world. The eye is an incredibly complex and sensitive structure, all finely tuned, so it’s not surprising that tiny abnormalities result in visual defects and lead us to need help to correct our sight.

For perfect sight, light has to enter the eye and focus on the back surface. If your eyeball is too long, you’ll be short sighted. If it’s too short, you’ll be long sighted. Specs or contact lenses position the light in the right place so you can see clearly. If the curve of your cornea, the clear window at the front of the eye, is imperfect, then this will also create a problem with focussing.

Light enters the eye through the pupil, the black hole at the centre of the eye. It travels through the crystalline lens, a transparent structure that changes shape to let us see both close up and far away. Muscles hold the lens in place and stretch and relax to alter its shape and therefore its focus. If the lens is not the perfect size and shape then this will add to the visual defect of the eye. So you can see that there are several reasons why you may need glasses or contact lenses.

Once your optical system has been corrected and is working as it should, light reaches the light sensitive layer, the Retina, which lines the back of the eye. Here the image we see is upside down and in reverse! It travels to the brain through the optic nerve, where thankfully it’s put the right way round.

Ophthalmologists and opticians are lucky in that they’re the only clinicians who can examine their specialist organ without cutting their patient open! Thanks to ever advancing screening equipment and retinal imaging systems we can see inside your eyes and spot the very first signs of problems. This fantastic and beautiful system works on our behalf for every minute of our waking day, so look after it by attending your check ups and taking a few minutes to appreciate and maintain it.


To Wear or Not to Wear?

Wednesday, March 24th, 2010

A common question that we’re asked is one that may seem to have an obvious answer. If I wear my glasses, will it make my eyes weaker? Will I start to rely on them? Some patients are clearly so concerned that they put themselves at risk by leaving their specs off unless they absolutely have to wear them.

So, why do we need glasses and how do they work? Put simply, you are short sighted if your eyeball is too long, and long sighted if it’s too short. Light is focused in front or behind the retina and your sight is blurred. Some visual defects are also down to irregularities in the surface of the Cornea, the clear area we look through at the front of the eye.

So, as the reason for your sight defect is physical, wearing glasses or leaving them off will not change your sight. All that happens is that your brain realises that life is easier with the specs on, and you get used to seeing clearly. This makes you feel reliant on them, but if you left them off for a day or two this effect would be lost.

At best you’ll get a headache if you don’t wear them, which will quickly improve once you put your glasses back on. At worst you could cause an accident by not seeing clearly and failing to react. Never drive without your specs if you’ve been told you need them to reach the driving standard.

Keeping your glasses on your face, where they belong, will keep the frame in good condition, and save any eye strain. They’ll always be there when you need them, and you’re utilising the gift of sight at it’s maximum standard. The good news is that leaving them off will not make your sight worse, so don’t panic if you do feel more comfortable under some circumstances without them on, it is allowed as long as you’re not behind the wheel!

Under Pressure

Friday, February 26th, 2010

The eye disease Glaucoma is a cause of blindness that can be easily treated if detected at an early stage, with the result of no loss of vision. As the patient often doesn’t suffer any symptoms until the disease has progressed, it is a definite reason to keep up to date with your eye examinations. Glaucoma occurs due to a build of pressure inside the eyeball. This happens when the fluid produced in the eye cannot drain away as it is meant to. The pressure builds and begins to affect the Optic nerve, which then reduces the sufferer’s field of vision. This usually happens so slowly that the patient is not aware of the problem.

Acute Glaucoma is a different issue, in that symptoms do appear, as the disease occurs suddenly. The eye will be painful and vision is quickly affected. Immediate treatment is vital to save sight. For either form of Glaucoma treatment may involve eye drops or surgery. Close monitoring is also vital, to keep the delicate balance between the in and out flow of fluid within the eye.

If you have Glaucoma then the NHS will pay for your sight tests, which should be done yearly. Close relatives over the age of forty will get their tests through the NHS too, as the problem can be hereditary. If you are diagnosed make sure your children, siblings and parents know and tell them to go for a check-up. The Optician screens for Glaucoma by reading the internal pressure of the eye, checking your field of vision, and examining the Optic nerve when they look into your eye. Usually pressure is checked by bouncing a puff of air onto the eye ball, to read the pressure. Older screening equipment needed anaesthetic drops so the eye could be touched, but nowadays the test is non-invasive. Field screeners emit flashes of light that you register to give a read out of your peripheral vision. There are different formats of tests, but all are quick and simple, and give a record of how good your field of vision is at a given time. When the Optician looks inside your eye with their ophthalmoscope they can examine the Optic disc and check for any changes or signs of high pressure. Subtle changes with any of these tests may be early signs of Glaucoma, so your Optician may refer you to the Hospital for further investigation. Always take their advice seriously and follow up warnings. It might just save your sight.