Eye Safety


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Repeatedly we were asked about the risk of injury when using a round shape on a Live Role Play Arrow. These concerns are legitimate. Therefore the following test was developed to quantify the stress applied to a human eyeball in case of a direct hit. As some people prefer the conventional flat shape, two common flat shape models were tested in direct competition.

Though the whole construction aimed at a minimum risk of eye injury it took a while to develop a comprehensible and clear test procedure.

As well as in other tests, the results show the outstanding safety of the IDV arrow in comparison to other common LRP arrows.

Nevertheless, technical precautions can NEVER EVER replace a sensible and responsible behaviour of the user him- or herself.
Stressing the bow more than necessary means giving away precious safety reserves and accepting negligently additional risks.

I also hope that this tests will finally end the discussion about which shape is safer. The answer is simple: "None. It depends on the whole construction and the interaction of the components."

These models were tested in comparison to the IDV-Safety-Arrow:



	Arrow 1: "Classical" design, as used in self-made arrows. A solid pressure-dirtributor is set behind a rubber plate. Glued Polyster foam, wooden shaft



	Arrow 2: Poly-Urethane Foam. One of the most common commercial arrows in the German LRP scene. Glass fibre - Shaft


	Both models were sold in LRP stores and were built in 2003 or 2004. When tested, they showed no signs of deteriation. The inner construction of the IDV-Safety-Arrow is shown and documented on the Site "Sicherheitskopf".

The Test procedure and the considerations it was based on.

The arrow's head to be tested was clamped to a press (in this case an industrial drilling machine) and pressed on a transparent piece of pipe (Outside diameter 50 mm, inner diameter 43 mm and therefore some larger than the human eye socket (30 mm)).
In the inside of the pipe there is a eyeball model made of modelling clay named "Modellin".

The modelling clay sphere fills the pipe exactly to the upper rim.

As shooting at this test equipment will hardly work (I do not hit the pipe), the arrow's head is pressed statically onto the pipe for three times for 2 – 3 seconds each: Once exactly in the middle, two times excentrically.


	The degree of compression of the eyeball model can be taken to estimate the risk of injury. However it seems impossible to state at which degree what kind of injury may occur. Nevertheless it is clear that an increasing compression means an exponentially increasing risk of severe injury.

The dial gauge provides a simple, yet precise way of measuring the force applied as the press bends up approx. proportionally to the applied force.
At the test stand 100 µm (0,004") equals approx. 250 N while 200 µm equals approx. 500 N, which is the weight force of a full size anvil !
While the total forces were only measured roughly with a bathroom scales, it was made sure, that all arrows were tested with exactly the same force

The arrow's heads were pressed onto the simulated eye socket with 250 N and 500 N. After that the compression of the clay sphere was gauged.

Comparable forces are found when a LRP arrow, from a 25 lbs. bow, hits a human head from short distance, with the distribution of the impact impulse between head and arrow considered.


	The results: This static test may deliver results which may seem more critical with some arrow models than a dynamic test would do. Therefore some arrows may look worse than they really are. However, it is extremely unlikely that an arrow will be worse in a dynamic test, after it delivered good results in this test


	IDV-Arrow at 3 x 250N: Compression approx. 7 mm


	IDV-Arrow at 3 x 500N: Compression approx 8 mm


	The IDV Safety arrow shows exactly the results it was designed for: The shaft is caught by the pressure distributor which braces the force equally and elastically onto the rim of the eye socket. The compression of the eyeball modell remains at the same low value even when the force is doubled. Therefore the danger of injury remains at a very low level.



	Arrow 1 at 3 x 250N: Compression approx. 8 - 9 mm


	Arrow 2 at 3 x 250N: Compression approx. 10 mm



	Arrow 1 at 3 x 500N: Compression approx. 12 mm Almost plane mark


	Arrow 2 at 3 x 500N: Compression approx. 15 - 16 mm Strongly concave (hollow) impression !

Ideas, Questions or Suggestions about this test procedure ?
I am looking forwards to an interesting discussion.

Deales and distributors are found at "Kontakte".