A prism has the same cross-section across the entire length of its shape. When used in eyeglasses, they often correct abnormalities associated with nearsightedness, farsightedness and double vision. Eyeglasses, or corrective lenses, reduce or increase the size of the image based on the eyes’ ability

Optical filters carefully transfer light in a specific range of wavelengths or colors while obstructing what remains. These dyed plastic or glass devices are placed in the optical path. They are described by their frequency response, and this identifies how the scale and stage of each frequency component

Rotation trainers consist of a disk – with various designs – that is attached to a rod-like base. As the disk rotates, the patient is asked to perform tasks that are designed to test and enhance eye-hand coordination, space awareness, perceptual awareness and visual acuity.

This entails a wall-mounted square board with a starburst design. Along the various striations of the starburst are lighted buttons. As the buttons light up, the patient works quickly to see how many of these lit buttons they can push before they go out. The key is to keep the head still. Peripheral

This device integrates all of the senses used for learning. It is one of the basic instruments used for visual-motor training, and helps with direction, rhythm, eye-hand coordination, and work and shape recognition. It consists of an aluminum case with illuminated membrane switches organized along a

Here, a ball with letters, numbers, colors, pictures, or a combination is hung from the ceiling. In activities used to help focus visual attention, the individual may be asked to concentrate on a figure while bunting the ball with a rod, or hitting or catching it with their thumbs, palms or fists.

Known also as optometric phototherapy, syntonics deal with the application of selected visible-light frequencies and are used to treat lazy eye and problems with peripheral vision and depth perception. By applying particular visible-light frequencies through the eyes, syntonics can improve vision. This

Amblyopia, commonly called lazy eye, refers to the improper development or significant loss of vision in an eye. It occurs when the brain does not acknowledge the images seen by the amblyopic eye. Amblyopia Causes Amblyopia occurs when an individual cannot use binocular vision (both eyes working together)

There are many potential causes for blurry eyes. The answer to why you have blurry vision is best answered by your eye care professional, who can offer diagnosis and prompt treatment so that your vision does not get worse. Some conditions that cause blurry vision are easy to treat, but others require

Double vision, also known as “seeing double” or the medical term diplopia, is the perception of two images of a single object. This occurs when two nonmatching images are sent to the part of the brain that processes visual input. Over time, the brain eventually begins to compensate for this misinformation

An eye condition affecting roughly 50 percent of individuals who need glasses, hyperopia (commonly called farsightedness) is characterized by difficulty focusing on nearby objects while being able to see objects at a distance properly. Hyperopia occurs when your eyeball is too short or when your cornea

In an ideal world, everyone would have perfectly-shaped eyes. The reality, however, is that practically every eye has some form of aberration somewhere in it. These aberrations may or may not cause vision problems, but don't be too surprised if your eye doctor informs you that you are having difficulties

The name conjures up pain, but ocular migraines are less about headaches and more about a vision problem. Ocular migraines are temporary visual disturbances that can last up to 30 minutes. This condition can affect one eye or both eyes simultaneously. An ocular migraine does not typically cause pain

Myopia, commonly called nearsightedness, is a refractive error of the eye, meaning that the shape of the eye or its cornea improperly bends light as it enters the eye. This hinders your ability to focus. Myopia is the most common refractive error of the eyes, and is caused by several factors including

Simply put, accommodative dysfunction means that the eyes have difficulty focusing properly. Studies suggest that between 2 and 17% of children may suffer from accommodative dysfunction. The nature of this disorder means that it sometimes goes unnoticed in standard vision screenings conducted at school.

Convergence insufficiency is a relatively common eye condition that is typically diagnosed in childhood. A study of two large optometry clinics found that 17.6% of children who received vision exams had convergence insufficiency. As this disorder may cause difficulty focusing on written pages, some children