Safety LASIK vs Contact Lenses

The truth about LASIK – could it be safer than contact lenses?

Posted by Dr David IM Robinson

Nervous of LASIK because of the risk of complications? Sticking with your contact lenses?  This post looks at the real risks of contact lens wear and whether LASIK might just be a safer option in the long term.

 

Contacts are safer than they used to be, right?

 

Corneal microbial infection is a rare but potentially catastrophic event, which can cause permanent scarring. It is associated with contact lens wear as well as laser eye surgery among other things.

 

Despite the inconvenience and discomfort, contact lenses have traditionally been seen as a safer option than laser eye surgery as a way of correcting shortsightedness and other visual errors. Recent studies, however, and have concluded otherwise.

 

The past decade has seen hundreds of millions of dollars being poured into research and development of new contact lens materials, designs and wearing modalities.

 

Despite this massive investment, studies show that while comfort has improved, the rate of contact lens-related serious eye infections remains the same.  How is this possible?

 

A medical device becomes a commodity…

 

One theory is that lenses are marketed more casually than ever before, especially one-day lenses, which many users purchase over the Internet for perceived cost savings.

 

Casual attitudes to hygiene, such as not washing hands thoroughly before handling, sleeping in lenses overnight or storing lenses in saline for a second use, all lead to a greater risk of infection. It is thought that these lax attitudes have cancelled out the advantages of better materials and more frequent replacement.

 

How does corneal infection occur?

 

The eye is an almost sterile environment. Unlike the mouth, which literally contains millions of bacteria, the eye has almost none, other than a few that fall in off the eyelashes and eyelids.  Even if bacteria get into the eye, the tears are a powerful antibacterial agent and the lids and lashes sweep them away immediately.  The cells of the outer later of the cornea – or epithelium – are so tightly joined together that bacteria just can’t get through.

 

So, in order to get microbial infection in the cornea (also called microbial keratitis) there must be a compromised corneal surface. These conditions can occur after laser eye surgery as well as in contact lens wear  (and severe dry eye and other ocular surface diseases).  Bacteria and other opportunistic pathogens can gain access to the deeper layers of the cornea and infection can take hold.

 

The microbes can come from anywhere, but there are some regular offenders, such as tap water, dirty hands and contact lenses and their cases.

 

 

Do all contact lenses carry the same risk?

 

Rigid gas permeable (also called RGP or hard) lenses are associated with the lowest risk of contact lens-related eye infections, at about 1 case per 10,000 wearers every year. But hard lenses do not enjoy widespread usage in Australia.

 

Daily wear lenses are associated with an annual risk of twice that of RGPs (2 cases per 10,000 every year).  Extended wear lenses (worn overnight) have an incidence of infection of 12 cases per 10,000 – or 6 times the risk associated with daily wear lenses.

 

The incidence of microbial keratitis per year after LASIK, has been calculated at about 4 cases per 10, 000 (.04%). This was found by averaging many studies around the world. This incidence may be lower in Australia, particularly with an experienced surgeon. This is twice the risk of wearing daily wear soft contact lenses for one year.  But extended wear lenses carry 3 times the risk associated with LASIK every year they are worn.

 

LASIK is usually performed once in a lifetime and so the risk is once off, while contact lenses carry their risk of infection year after year.  (The studies factored in a 10% retreatment rate for LASIK and the results varied very little).

 

By your third year in soft lenses, the risk of a corneal infection is higher for contact lens use than for LASIK, especially where extended wear lenses are worn.  But laser vision correction provides lifestyle advantages and freedoms over contact lenses, especially for travel, water sports and day-to-day convenience and comfort.

 

 

Had enough of uncomfortable contact lenses? Looking for an alternative? Call 1800 25 20 20 and make an appointment with Dr David Robinson today.

 

References

 

Risk for microbial keratitis: Comparative meta-analysis of contact lens wearers and post-laser in situ keratomileusis patients

Journal of Cataract & Refractive Surgery (JCRS) Vol 43 Page 67 January 2017

 

 

 

 

 

 

 

 

 

 

How Smoking Increases Your Chances of Eye Disease & Permanent Loss of Vision

Tobacco smoking harms every single part of the body and can penetrate every organ via the blood stream. Our eyes are therefore just as vulnerable to permanent damage from smoking as our lungs and heart.

Over the decades numerous studies have been conducted to determine the exact effect smoking has on the human eye. These studies have produced evidence, which reveal some frightening statistics.

Here is a brief overview of the effects of smoking on the human eye:
As we get older our chances of developing cataracts naturally increases. However an individual smoker doubles their chances of cataracts and the longer a person smokes the more the risk increases.

‘Macular degeneration (MD) is the name given to a group of degenerative diseases of the retina that cause progressive, painless loss of central vision, affecting the ability to see fine detail, drive, read and recognise faces’ (www.mdfoundation.com.au) The effects of macular degeneration are permanent, irreversible and a cure is yet to be found. Studies have discovered that smokers more than triple their vulnerability to macular degeneration. Even more terrifying is the discovery that females (who’ve smoked for most of their lifetime) over the age of 80 are 5.5 times more susceptible to macular degeneration.

A lesser-known eye disease called Uveitis was found to be 2.2 times more likely to develop in smokers than non-smokers. Uveitis occurs when the ‘uvea’ the middle layer of the eye becomes inflamed. The disease also damages the iris and retina, which are the central structures of the eye and increases risk of cataract, glaucoma and retinal detachment.
The US centre for Disease Control and Prevention has found that smoking can nearly double the risk of developing diabetes. Diabetes can cause retinopathy, a disease which damages the blood vessels within the eye causing complete vision loss. There is further research to be conducted into the link between smoking and adult onset diabetes.

A seemingly less severe eye problem that most believe can be treated with over the counter eye drops is Dry Eye Syndrome. However, dry eye syndrome can be difficult to treat and even more difficult to live with. Cigarette smoke is widely known as an eye irritant causing great discomfort, irritation, itchiness, redness and the constant sensation that there is a foreign body in the eye. Dry eyes is twice as common on smokers and those exposed to tobacco smoke (second-hand
Smoking not only harms your own eyes but if you are pregnant you greatly increase the chance of harming your unborn babies eyes permanently. The dangerous toxins from tobacco enter into the mother’s bloodstream and then flow directly to the placenta – this is the baby’s lifeline whilst in the womb.

A common effect of smoking whilst pregnant on babies is strabismus ie. Cross-eyes and can prevent complete development of the optic nerve – this is a leading cause of blindness in children.

Smoking whilst pregnant significantly increases your chances of giving birth prematurely. Any baby born prematurely is more vulnerable to developing permanent eye disease.

25 Awe Inspiring Facts About the Human Eye

The human eye truly is an incredible feat. Here are 25 fun and fascinating facts that will certainly make you appreciate the marvel of these two little organs.


1.
Every human in the world is born colourblind

2. Every human in the world is also born without the ability to produce tears. Even though we are making crying sounds our tear ducts only start working when we are 4-13 weeks old.

3. Not everything is going to get bigger as you age. Your eyeballs stay the same size throughout your entire life. From the day you are born till the day you die your eyes do not grow.

4.
In the blink of an eye. 1/10th of a second is the average length of a blink.

5. Ever wondered why reading helps you feel tired? You actually blink less when you are reading. This can cause the eyes to feel a bit more dry and exhausted than usual.

6.
Each year on average you blink 5.2 million times. A 14- hour day will see you blinking 14,820 times and that means 17 blinks a minute.

7.
Why do we blink? Each time we blink our eyelids clean and moisten the eyeball keeping it healthy and stopping it from drying up. Blinking is also an automatic ‘survival’ instinct – if something were heading in the direction of your eye it will start blinking straight away.

8. Our 28-gram eyeballs each contain 107 million cells that are sensitive to light. This means every cell receives visual messages from what it is exposed to. 7 million of these cells are called cones; these help us see sharp details and colours. The other 100 million cells are called rods and help us to see in the dark.

9. The human eye can see the difference between around 10 million shades of colour.

10.
Every hour our eyes can process 36,000 bits of information to our brain.

11. The most active muscles in our body are those controlling our eyeballs.

12.
The eyes never sleep. The human eye is the only part of our bodies that can function at 100% of it’s abilities day or night, whenever we need them. They don’t actually get tired!

13. What determines whether or not you have brown or blue eyes is the level of Melanin in your iris. Melanin is a dark brown pigment. The more Melanin the darker the eyes. The less melanin the more the collagen in the eye can come through which is blue.

14.
It is believed that all blue-eyed humans have common ancestory. The first pair of blue eyes date back 6000-10,000 years ago. Prior to blue eyes everyone had brown eyes.

15.
The choroid, which is located behind the retina in our eyes, is jam packed full of blood vessels. This is why we get red eyes in photos. When the light flashes it reflects the light from the back of the eye giving the eyes a red colour in the printed photo.

16.
The only living tissue in our bodies that does not contain any blood vessels is the cornea.

17.
The brain actually creates the colour red for us. Our retinas can’t detect a plain red colour. The yellow and green receptors pick up a blue green and then the brain mixes the colours to create red.

18. Men are 10 times more likely to be colour blind than woman.

19.
Our peripheral vision is very low-resolution and picks up visuals in nearly complete black and white.

20. Just like our brains create a variation of colours for us, it also puts things straight. When our retina receives a visual message it is actually upside down and when it hits the brain it rotates the image to its actual position. Even more than this, our eyes and brain work together to create whole visuals. Not are the images just upside down when they get to the retina they are split in half!

21. Some say that up to 80% of our memories are developed by what we see.

22.
Humans and dogs have a very special ability. They are the only 2 species on the planet that actively seek visual cues from other individuals. Dogs only look for visual cues when they are interacting with humans.

23.
Eyelashes and Eyebrows. Not just there to accentuate our facial structure. The eyelashes act as dust and dirt catchers. Whilst our eyebrows are sponge for any sweat that might drop down our forehead into our eyes (it actually does sting)

24. Why does our nose also have to get runny and overwhelmed when we cry? The tears run down the back of our eyeballs into our nasal passage.

25. People with longer eyeballs than normal are called shortsighted. Those with shorter eyeballs are called farsighted