Computer games could be good for your eyes

Posted on April 23, 2013 by Ian

It’s not the sort of advice you might expect from your optometrist but current research from McGill University in Canada suggests that playing the video game Tetris may be an effective way of improving a lazy (amblyopic) eye.

Good vision requires more than just a healthy eye. The eye sends electrical signals via the optic nerve to the part of the brain used for visual processing. We call this process the visual pathway or visual system. The visual system is not fully developed at birth. Good development requires each eye to be seeing well in order to build the connections between the eye and the brain. If one eye sees better than the other, the connections it builds will be stronger, leading to a dominant eye that suppresses the other one. This development continues from birth until about 8 years old.

During this time there is a chance to balance the two eyes by covering the stronger eye forcing the weaker eye to behave better. This is only successful in some children and generally accepted not to work in adults at all. The earlier that treatment is started the better the outcome. This is why eye testing from about 3 years old is advised in all children. This should be even earlier if you have a family history of eye problems, if you think you see a squint in your child’s eyes or have any concerns that they are not seeing well.

So could video games offer the answer to improving vision in adults who currently have no other treatment options? By connecting differently shaped blocks as they fall in Tetris, the eyes are forced to cooperate with each other, alleviating suppression of the weaker eye and retraining the brain to use both equally. Results from recent research suggested promising improvements in the vision of the weaker eye and in 3D perception.

Unfortunately kids, this has not been trialed on children yet, although an American trial is planned for later this year. So while we are not advising video games over homework quite yet, this might bag you another few minutes on your DS!

Eye scan can monitor the extent of MS

Posted on February 12, 2013 by Ian

As you may have noticed at your eye appointments over the last couple of years, in addition to taking a retinal photograph of your eyes we offer a scan of the deeper retinal layers, using our Optical Coherence Tomographer (OCT) scanner.

Being one of the first practices or hospitals to have this equipment in Edinburgh we have been learning more and more of the value of these scans as our experience grows and research continues. The most recent neurological research suggests that OCT measurement of the retinal thickness may offer a fast and effective way to monitor progression of Multiple Sclerosis (MS) The research suggests that patients with relapsing MS had rates of retinal thinning up to 42% quicker than those without replases. Perhaps as more therapies are developed to slow MS progression testing retinal thickness will be a useful tool in monitoring how effective these treatments are.

As ever, the eye provides a window to the health of the rest of the body. While we use the OCT more commonly to detect and monitor early signs of eye disease, particularly glaucoma and all types of macular degeneration , we also see the value in having these scans done in your healthy eye to establish baseline data that could be invaluable in the future.

AAO 2012 Phoenix – Day 1: A nerd’s paradise

Posted on October 25, 2012 by Ian

If you love eyes, AAO is like Nirvana. Is your chance to be as nerdy as you like about eyes and no one thinks you’re weird or boring!

I only made it to 4am before I was wide awake but fortunately had a 7.15am start with a breakfast meeting about contact lenses and happy patients. It was OK but I wasn’t inspired to be honest.

Things improved as the day took a decidedly geek turn with a whole hour devoted to the the vitreous humour (of course the Yanks spell it incorrectly). For those of you casting your mind back to A-Level biology the vitreous is clear the jelly like substance that fills most of the eye ball and is 99% water. How can you talk for an hour about a transparent bag of gel that’s 99% water I hear you ask? Well you can and it’s fascinating.

If any of you have experienced flashes and floaters then you may have had a PVD which we talked about in some detail. There is even hope for a new treatment for problems associated with PVD and a possible cure for floaters. This new wonder drug comes out in the US in 2013, so we’ll have to see how long it takes to come to the UK.

Then I had an excellent summary of the latest lenses for keratoconus. We’re pretty much at the leading edge of keratoconus in the UK and so there wasn’t too much new here but there are a couple of new designs coming out this year which sound quite exciting and now I know how to fit them, it should give us a running start when the arrive in the UK.

The afternoon was a bit of binocular vision (how the eyes work together as a pair) and a very interesting discussion of the value of OCT in Glaucoma and other optic nerve analysis. The OCT is scanner that we will have used on you if you’ve come in for an eye exam in the last year or 2.

I’m such a party animal I stayed up until 8pm before crashing out!

AAO 2012 Phoenix – Day 2: A view into the future

Posted on October 2, 2012 by Ian

Well day 2 has been even better than day 1 although it was another 4am start. I’m like a kid in a sweet shop, there are so many interesting lectures I’m having a hard time choosing.

I opted for “What’s new in retina” which was a good choice. The chap (a retinal surgeon) was giving us a sneak peak at some brand new (not even released or published) information about some very exciting new drugs available to treat macular degeneration. You may have heard of Lucentis which is widely used but this next generation drug is used in combination and looks to have incredible results. This kind of research just isn’t accessible in the UK which makes the effort of coming out here feel very worthwhile and exciting to see what’s coming round the corner.

A bit more stuff on injections for macular degeneration rounded out the morning and has given me some rather exciting ideas for where we could go in the future with optometry in Scotland.

The afternoon was a workshop on “Advanced Retinal Examination – 3 mirror and scleral indentation” which is not as bad as it sounds. This was a great chance to practically brush up on some skills to examine the peripheral retina to check more thoroughly for problems like retinal detachment. It was so useful I went an bought a new lens to put my new skills into practice in Scotland and take advantage of the great exchange rate.

Tonight I ‘partied’ until 8pm again but stayed up catching up on emails until 9pm!

Long eyes less likely to have diabetic retinopathy

Posted on September 9, 2012 by Ian

Finally some good news for the short sighted as people with long axial lengths (that is the length of the eyeball, front to back) are less likely to suffer from diabetic eye disease.

Myopia or shortsightedness is where rays of light are focussed in front (or ‘short’) of the retina rather than on it leading to blurry vision. It is easily corrected optically but high myopia can cause many physical problems as the eye is usually larger than normal which causes the focussing short fall – the retina is too far away, if you like.

Myopia is described as pathological when you get up to the doubel digits on your prescription and is linked to an increased risk of a form of macular degeneration, glaucoma and retinal detachment. The larger sized eye means the retina is streched thin over a larger area and so is more fragile and prone to damage.

This study showed that the longer your eye the less likely you are to have all forms of diabetic retinopathy (mild, moderate, severe). It’s rather interesting as it flies in the face of almost every other condition. The authors didn’t speculate why they through this might be the case but it will undoubtedly lead to more research as an estimated 1-2 billion people have myopia and 300 million have diabetes worldwide.

Glaucoma plugs could stop the need for drops

Posted on September 8, 2012 by Ian

A trial of a new method of delivering glaucoma medication by using a slow release punctum plug has started.

Glaucoma usually requires patients to permanently take drops once or twice a day to reduce pressure inside the eye. Patients often find it difficult to remember to take the drops or hard to get them int the eye and methods which overcome these issues would be very useful.

After an initial small trial in Singapore showed promise, this longer South African trial uses a punctum plug containing the popular glaucoma medication travoprost (Travatan) which is taken in drop form once a day. The plugs will be trialled over a period of 2 months with pressure being monitored regularly for any signs of change.

Punctum plugs are normally used for helping treat dry eye by blocking the tear ducts

Bionic eyes shows continued success

Posted on September 2, 2012 by Ian

An Australian group have restored some minimal sight to a patient through an implanted bionic eye.

The implant is connected to an external head mounted camera which sends impulses to electrodes planted underneath the retina. The patient was able to see light and dark and some shapes where she had previously seen nothing for many years.

There are currently over 10 different bionic eye projects around the world at various stages but no one to date has got much further than providing very rudimentary vision. One of the most advanced is the Argus II model in America.

Totally distortion free lens created

Posted on August 25, 2012 by Ian

It’s actually even better than the title suggests as boffins at Harvard have created a ultrathin lens that focusses light without creating any image distortion of any kind at all.

Without going into too much of the detail, lenses focus light but altering the direction and speed of light rays passing through the material. The amount of material a light ray passes through and the curvature of the 2 surfaces of the lens affect the direction light. Varying the thickness and curvature of lenses in different parts of the lens bend rays differently, focussing them or spreading them out as required.

Sort of.

All this bending of light rays causes lots of aberrations which are the names of unwanted optical distortions. Some of these you will have heard of eg defocus (such as in long and short sight) and astigmatism; but there are lots of others you probably won’t have eg coma, Petzval field curvature and so on. All these aberrations degrade the quality of the final image. We design your glasses lenses with special combinations of thickness and curvature to minimise these aberrations but you can eliminate them entirely.

If you are wearing glasses, look out through the edge rather than the centre of your lens at something white like your ceiling. You might see some coloured fringes, look through the other edge and you might see the fringes are now a different colour. This is a type of aberration called ‘chromatic aberration’.

If you’re quaffing a glass of vino, hold up the empty glass to something square behind it like a picture frame. The frame is all distorted and mishapen, this is an aberration called ‘distortion’.

This new Harvard lens has only one surface and is effectively 2 dimensional (60 nanometres thick) and not very like a lens as you would think of it. It uses tiny little V shaped ‘antennas’ made of a layer of gold on a silicone wafer. The little Vs alter the speed of light waves instantly and they don’t require passage through a material to change direction. Altering the size and position of these ‘V’s across the surface alters the lens properties.

It’s quite obvious how a such a thin lens would be helpful in any optical system (including glasses) from a physical point of view, but the lack of aberrations is also very exciting. Super vision lenses are within our grasp!

Potential cure for Dry AMD

Posted on August 11, 2012 by Ian

There has been a breakthrough in the treatment of the previously untreatable form of macular degeneration (‘dry AMD‘).

Kentucky vision Scientists have discovered the complex chain reaction of proteins and enzymes that happens in the retina causing dry AMD. They demonstrated that using drugs to selectively block these proteins and enzymes halted the process in various disease models.

There has been no trial on humans yet but this gives hope to millions suffering from dry AMD. Usually taken to be the unstoppable ageing process of the retina, dry AMD can get progressively worse with no effective treatment options. This new breakthrough could open up a whole raft of drug therapies to halt or prevent the condition developing.

Caffeine raises eye pressure

Posted on August 9, 2012 by Ian

A big and seemingly well designed study has shown the effect of caffiene on intraocular pressure (IOP).

106 patients split into 4 groups (3 types of glaucoma, 1 no glaucoma) and were seen twice. Before 1 visit they were given caffeine or decaf coffee and then the opposite on the second visit. The study was double blind meaning neither the researchers taking the measurements or the participants knew if they had had the decaf or the fullcaf drink.

The results showed that IOP is increased by about 1 unit after caffeine with maximum effect at about 90minutes but the effect is temporary and not very great so needn’t concern coffee lovers with glaucoma.

Previous studies had put the frighteners on some folks with glaucoma claiming coffee was bad for the condition, but this study will hopefully let them enjoy a cappuccino in peace.

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