Search results
Results from the WOW.Com Content Network
Individuals with nystagmus, Duane's retraction syndrome, 4th Nerve Palsy, and other eye movement disorders experience an improvement in their symptoms when they turn or tilt their head. Yoked prism can move the image away from primary gaze without the need for a constant head tilt or turn.
The distance in micrometers between the actual wavefront and the ideal wavefront is the wavefront aberration, which is the standard method of showing the aberrations of the eye. Therefore, aberrations of the eye are the difference between two surfaces: the ideal and the actual wavefront.
Eye glasses with an included prism power is the optical method to reduce a fixation disparity. Different procedures have been proposed to determine the required amount of prism for the individual. Based on prism-FD curves (Fig. 3b), one can find the aligning prism sP 0 that nullifies the naturally prevailing fixation disparity sFD 0. This test ...
Symptoms include chronic headaches, dizziness, and reading difficulties, even with 20/20 vision using corrective lenses. The effort to correct eye misalignment causes eye strain, leading to a range of symptoms that complicate diagnosis and treatment.
Causes. Hypertropia may be either congenital or acquired, and misalignment is due to imbalance in extraocular muscle function. The superior rectus, inferior rectus, superior oblique, and inferior oblique muscles affect the vertical movement of the eyes. These muscles may be either paretic, restrictive (fibrosis) or overactive effect of the muscles.
Symptoms. The symptoms and signs associated with convergence insufficiency are related to prolonged, visually demanding, near-centered tasks. They may include, but are not limited to, diplopia (double vision), asthenopia (eye strain), transient blurred vision, difficulty sustaining near-visual function, abnormal fatigue, headache, and abnormal ...
Treatment varies for micropsia due to the large number of different causes for the condition. [citation needed] Treatments involving the occlusion of one eye and the use of a prism fitted over an eyeglass lens have both been shown to provide relief from micropsia. Micropsia that is induced by macular degeneration can be treated in several ways.
Presbyopia is a typical part of the aging process. [4] It occurs due to age related changes in the lens (decreased elasticity and increased hardness) and ciliary muscle (decreased strength and ability to move the lens), causing the eye to focus right behind rather than on the retina when looking at close objects. [4]
Symptoms. When the eye position is fully corrected (for example after surgical alignment of the eyes) or when the patient is provided with the best achievable prism correction, the patient does not experience binocular fusion and, instead, sees a double image that is very close to the fixation image and is perceived as "dancing around" it.
The prism cover test (PCT) is an objective measurement and the gold standard in measuring strabismus, i.e. ocular misalignment, or a deviation of the eye. It is used by ophthalmologists and orthoptists in order to measure the vertical and horizontal deviation and includes both manifest and latent components. [1]