Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Excellent Underwater Vision Examined by Scientists from Lund

15.05.2003


We humans are poorly adapted for underwater vision. However, the Moken peoples of south-east Asia manage to collect shells, clams and sea cucumbers using no visual aids when diving to a depth of 3 or 4 metres. Scientists from Lund University in Sweden have now measured the visual acuity of these children and have found that their ability to see well underwater is not a myth: their acuity in this environment is indeed superior to that of European children. The scientists have also found an explanation for this phenomenon.



The results are presented in the new issue of the prestigious scientific journal Current Biology. Anna Gislén and Marie Dacke from the Department of Cell and Organism Biology have travelled several times to the Surin Islands (Thailand) where the Moken tribe live. These people are the so-called sea-gypsies, who for thousands of years have lived on their boats and collected food from the ocean. Some of them have settled down in houses built on three metre high stilts by the shore. At high tide the Moken can dive directly into the water from their houses.

Gislén and Dacke have performed a series of visual tests on the Moken children. Using an experimental apparatus placed under the surface, the children viewed striped patterns that were presented either horizontally or vertically. By using thinner and thinner stripes they could determine the resolution limit of the children.


”Underwater, Moken children can resolve stripes that are twice as fine as the finest seen by European children”, says Anna Gislén. ”We asked ourselves if this was due to a biological, possibly genetic, difference or if it was due to learning. For instance, we examined their eyes in detail, but could find no evidence that their corneas had a different curvature than the corneas of European children. Neither was there any evidence that the Moken children had better acuity on land.”

Was there something that these children did underwater that gave them better acuity? Under normal circumstances the pupil opens underwater to let in more light. But the pupils of Moken children constrict under water. The effect is the same as choosing a smaller aperture in a camera: focal depth is increased and resolution is improved. The Moken children also accommodate maximally, that is, the muscles controlling the lens are constricted and the lens changes shape, thus increasing the refraction of light.

”We are currently doing a follow-up study on Swedish children. Even though the study is not yet finished, it does seem that children can learn to adapt their eyes for better underwater vision”, says Marie Dacke.

Göran Frankel | alfa
Further information:
http://www.lu.se

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>