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Monthly Archives: June 2013

Bacteria and Eye infections: good news

The Journal PLoS One has published a recent study on how good bacteria can counter-act and fight bad bacteria, found in the eye, that are becoming more resistant to antibiotics, infect the eye and can lead to blindness.

The bad bacteria in question are Serratia marcescens and Pseudomonas aeruginosa. The good bacteria are Micavibrio aeruginosavorus and Bdellovibrio baceriovorus.

Here’s how they tested both in a three-part experiment.

The first part of the research was conducted to see whether the first two (the bad bacteria) actually die because of the last two (the good bacteria).

The second a third experiments were done to see whether the ‘good’ bacteria are actually not harmful to the eye. The second tested the bacteria on the cells that are present in the human eye. The results were that the bacteria did not inflame or irritate the eye cells at all.

In the third experiment, they tested again the bacteria against worms. While the worms died quickly after the injection of the bad bacteria, they had an 11-day survival rate (survival between 93.3 and 100%) after the injection of the good bacteria, suggesting that the bacteria was not harmful to their existence.

After these preliminary tests that exhibited very positive results, we await new tests and research on humans, as it seems that the good bacteria, or predator bacteria, can live in the eye without causing any damage to it and can help eliminate the bad bacteria, or the pathogenic bacteria.

For more information on this research, please visit: http://www.sciencedaily.com/releases/2013/06/130620191955.htm


What is strabismus?

Strabismus (often called crossed eyes or squint) is a disorder that affects the eye muscles, causing the eyes to look in different directions and on different things at any one time. Either one or both eyes may look inwards, outwards, upwards or downwards. This misalignment may occur all or some of the time, and may affect the same eye always or alternate between the eyes.

How common is strabismus?

Strabismus is estimated to occur in up to 5% of children, although adults can also develop the problem.

What does strabismus do to eyesight?

Early in the disorder, people with strabismus experience double vision and confusion because the eyes are not focusing on the same thing. Eventually, the view from the ‘turned’ eye will be ignored (suppressed) by the brain as it tries to prevent seeing double. The view of the world is not three-dimensional; it lacks depth and distance. Left untreated, constant eye turning can result in reduced vision in the eye (or Amblyopia, also known as lazy eye).

What causes strabismus?

While strabismus tends to occur in children at a young age, it may also develop in older children and in adults. Complications and injuries to the eye muscle are causes of strabismus. However, strabismus frequently arises from defects in nerves that send signals to the eye muscles or in the part of the brain that controls eye movements. Strabismus is a heritable condition and therefore can run in families. It can occur in people with other disorders, such as Down syndrome and cerebral palsy, or who have had a stroke or head trauma. Strabismus may also arise in people who continually try to correct their far-sighted vision.

Testing for strabismus

Normally, it is advised that all children have their eyes examined at about nine months of age. However, regardless of age, advice should be sought for any notable eye problem.

A complete medical history of the patient is taken, including family history of eye problems and the patient’s general health, other diagnoses and medicines. Essential to the diagnosis, is a detailed history of the eye problem, such as when it began and the nature of the eye turning. For a confirmed diagnosis of strabismus, the eyes are given a thorough examination. This includes observing the eye parts, and tests for visual acuity, alignment, focusing, and refraction (lens strength).

How is strabismus treated?

Treatment of strabismus is necessary as it will not disappear with age and may worsen. Treatment aims to improve the alignment of the eye and enable the eyes to move in a coordinated fashion. It will depend on the characteristics of the condition.

Prescription eye glasses may be used to get rid of eye turn and other problems with vision, such as farsightedness. An eye patch can be worn over the ‘good’ eye to encourage the ‘lazy’ one to function properly. Prism lenses, which change the course of light entering the eye and reduce the extent of eye movement required for the eye to focus, can sometimes correct the problem. Lenses may be all that is needed when the condition is mild but, more often, vision therapy and/or surgery are also required.

Vision therapy aims to improve movement, coordination and focusing of the eyes. The series of eye exercises re-establishes normal vision by educating the eyes and the brain to function together, the eyes to move together, and the brain to effectively merge the images from both eyes into one. Vision therapy is very effective and the improvement is long-lasting.

Surgery performed on the eye muscles aims to align the eyes and make the turned eye appear straight. It involves altering the length or moving the eye muscles. Surgery improves the cosmetic appearance of the eye but may not correct vision, particularly if the problem is not with the eye muscles only. This means that vision therapy may also be recommended to coordinate eye and brain functioning.

‘Lazy Eye’ treated playing Tetris?

This week we want to discuss a recent study that suggests that amblyopia, commonly known as ‘lazy eye’, can be treated by playing tetris.

First, though, it is best to discuss and talk about what the condition actually is.

What is Amblyopia?

Amblyopia is a lower-to-standard acquisition of images through vision. It can happen because the optic nerve is not transmitting the visual messages properly, or when the brain stops acquiring the image from one eye.
Why would the brain do that?
The brain can stop getting an image from one of the eyes because of different reasons. For instance, it could be due to strabismus. In this case, it happens when the brain perceives the images from the two eyes to be different (i.e. it understands that double-vision is occurring).
How can Amblyopia be treated?

Amblyopia is not an intrinsic neurological problem. Rather, it is an acquired bad habit. In patients with amblyopia there is nothing wrong with the eye itself. Hence, because it is a problem of developmental nature, the brain can be re-taught to “see” from the weaker eye.
Since now, most of the treatments were thought to be effective only in children. The main treatment was to occlude the strongest eye, either with an eye-patch or by applying drops of atropine. This would force the brain to acquire the image from the weakest eye, and would strengthen the communication between the two.
What is this new research showing?

The aforementioned treatment applications have not been successful with the majority of adults. This recent academic report, however, has found a new approach that can help adults with amblyopia. This report was published in the journal Current Biology and conducted by Li et al. The researchers have found that the brain still maintains a level of plasticity in adulthood. However, it has not been tackled in the right way. This research suggests that covering the strongest eye might be detrimental, indeed, to curing amblyopia. What these researchers did was to force the eyes to work together.

Why tetris?

Here’s where tetris comes along: one eye was forced to see the blocks falling and the other eye was only allowed to see the ground where they would fall. After two weeks, patients had already improved vision. Further studies are needed to confirm whether covering the strongest eye might indeed not be the best treatment to cure amblyopia. In any case, this remains an interesting research. The journal article of this research can be found here.