SightRight
The from Winmau developed SightRight based on a patent of Steven Feeney is an auxiliary for dart players.
On puts it under the board so that the white line in the middle of it starts directly under the bull.
With the help of the SightRight a dart player gets in the habit to always stand at the same place in the centre of the oche and it will help to avoid parallax errors.
Parallax errors are quite common in all sports in which it is important to align right and to throw, strike or push as in darts, golf or snooker. Might be you experienced it when putting, you thought you had aligned yourself and your club right and the ball would roll into the hole or over an obstacle but it didn't happen. Usually that is not an faulty course but an parallax error.
In darts it will show when you think you have aligned right to hit the twenty but your darts land in the five or one - it's some kind of "bend" in your vision.
To stand always at the same place at the oche is one of the requirements to develop a solid throwing action which will improve your accuracy. When you stand exactly in the centre of the oche you'll stop to aim across your body and you'll reach the whole board without to have to move around.
SightRight is easy to use, the explanatory notes are intelligible, detailed and to be followed without problems. They include some more tips how
to optimise the throw as there of course might exist other possible flaws in your technique.
Of course no one can guarantee success to 100 percent especially as their exist people who have no problem with alignment and throwing on the line at all. Those have to look somewhere else for reason for their inaccuracy.
But the "bend" in the vision is so common that global darts really recommends SightRight as an useful tool to improve accuracy and to find your "ideal" stand at the oche especially as the price is very reasonable - it's worth to give it a try.
One can buy SightRight at numerous online shops, the price is around 14.90 pound.
Here the link to three videos in which Steve Feeney and Simon Hall from Winmau give some more information to SightRight and it's mode of operation:
Video 1
Video 2
Video 3