The eye is essentially a camera, and its camera film is known as the retina, a very specialised structure that senses and processes light. The central part of the retina is known as the macula, which is responsible for detailed central vision including reading and recognising faces. In most people the vitreous gel, which fills most of the eye, naturally and gently separates away from the retina with age. However in some people, it can be abnormally strongly attached to the macula causing pulling or traction (see vitreomacular traction). If the traction is sufficient it can cause a small full–thickness hole (FTMH) to form in the very centre of the macula. Because of this location, even a very small hole can cause symptoms. If the hole does not involve the full-thickness of the macula, we term it as a partial thickness or lamellar hole, and generally does not affect the vision as much as a FTMH.