Accommodating spasms eye
Accommodation decreases to about 1 dioptre at the age of 70 years.
The dependency of accommodation amplitude on age is graphically summarized by Duane's classical curves.
This process can occur in as little as 350 milliseconds. By the fifth decade of life the accommodative amplitude can decline so that the near point of the eye is more remote than the reading distance. Once presbyopia occurs, those who are emmetropic (do not require optical correction for distance vision) will need an optical aid for near vision; those who are myopic (nearsighted and require an optical correction for distance vision), will find that they see better at near without their distance correction; and those who are hyperopic (farsighted) will find that they may need a correction for both distance and near vision.
Note that these effects are most noticeable when the pupil is large; i.e. The age-related decline in accommodation occurs almost universally to less than 2 dioptres by the time a person reaches 45 to 50 years, by which time most of the population will have noticed a decrease in their ability to focus on close objects and hence require glasses for reading or bifocal lenses.
Algorithm of examination of a child with suspected spasm of accommodation includes the determination of visual acuity, and spasms volume of a stock of accommodation, refractometers, skiascopy, study convergence.
Drug therapy with spasm of accommodation involves the instillation of eye relaxing the ciliary muscle tropicamide, phenylephrinevitamin spasms.
If the cause spasm of accommodation are the diseases of the spine, the patient may be recommended a course of therapeutic massage of accommodating area and back, accommodating, accommodaing therapy, therapeutic exercise.
Spasm of accommodation accommodating one of the most common diseases in pediatric ophthalmology, occupying second place after the short-sightedness.
Up to a certain point accommodation spasm is reversible, but the long nekorrigiruemaya false myopia may eventually go into a true myopia in children.
Arguably, it may increase the depth of field by reducing the aperture of the eye, and thus reduce the amount of accommodation needed to bring the image in focus on the retina.
Duration spasm of accommodation can vary from several months to several years, often moving in spasms resistant school myopia.Fish and amphibians vary the power by changing the distance between a rigid lens and the retina with muscles.