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Computer vision syndrome (CVS) is a condition resulting from focusing the eyes on a computer or other display device for protracted, uninterrupted periods of time and the eye's muscles being unable to recover from the constant tension required to maintain focus on a close object.
There is some confusion over how the focusing mechanism of the eye works. [clarification needed] In the 1977 book, Eye and Brain, [13] for example, the lens is said to be suspended by a membrane, the 'zonula', which holds it under tension. The tension is released, by contraction of the ciliary muscle, to allow the lens to become more round, for ...
When an eye focuses light correctly on to the retina when viewing distant objects, this is called emmetropia or being emmetropic. This means that the refractive power of the eye matches what is needed to focus parallel rays of light onto the retina. A distant object is defined as an object located beyond 6 meters (20 feet) from the eye ...
This dilation may pose a problem since a larger pupil is less efficient at focusing light (see pupil, aperture, and optical aberration for more.) Patients who have accommodative spasm may benefit from being given glasses or contacts that account for the problem or by using vision therapy techniques to regain control of the accommodative system.
It results in decreased vision in an eye that typically appears normal in other aspects. [1] Amblyopia is the most common cause of decreased vision in a single eye among children and younger adults. [1] The cause of amblyopia can be any condition that interferes with focusing during early childhood.
Both of these mechanisms are crucial in stereoscopic vision. Vergence or independent inward/outward rotation of eyes is engaged to fixate on objects and perceive them as single. Incorrect vergence response can cause double vision. Accommodation is the eye’s focusing mechanism and it is engaged to produce a sharp image on a retina.
Myopia is the most common eye problem and is estimated to affect 1.5 billion people (22% of the world population). [ 2 ] [ 4 ] Rates vary significantly in different areas of the world. [ 2 ] Rates among adults are between 15% and 49%.
The experience of eye strain when reading in dim light has given rise to the common misconception that such an activity causes permanent eye damage. [3] When concentrating on a visually intense task, such as continuously focusing on a book or computer monitor, the ciliary muscles and the extraocular muscles are strained. This causes discomfort ...