Parents should keep an eye out for children who have problems viewing 3D films as it could be a sign of sight problems, leading UK optometrists say.
Britain's Association of Optometrists says children who have problems with their vision can often go undetected as they are unaware their sight is not normal.
As difficulty watching 3D films could be a sign of visual problems, parents should be on the lookout for any adverse effects.
Signs parents should look out for include dizziness, headaches or visual discomfort or not being able to see the 3D effect.
To get the full 3D effect a person needs good binocular vision, where both eyes see clearly and work together properly allowing good perception of depth.
"Difficulty watching 3D films comfortably can be an early sign of visual problems," said AOP clinical and regulatory officer Henry Leonard.
"To be able to get the full 3D effect and view the film comfortably, you need good binocular vision.
"Children need a clear, sharp image in each eye in order for their vision to develop properly. If something upsets that balance, it can lead to reduced vision - known as amblyopia - in one or both eyes and poor 3D vision. If the problem only affects one eye it can easily go unnoticed, resulting in a 'lazy eye'.
"If children struggle to watch 3D films or fail to appreciate the 3D effect, this could be an early sign that they may be suffering from these kinds of visual problems."
The organisation has created a video for the public to help raise awareness of 3D warning signs which can be viewed at the www.aop.org.uk/patients website.
