Accommodating the eye is a process that allows the eye to see objects at different distances. Like many other mechanisms, it weakens with age. Patients experience this as blurry vision of objects, necessitating the use of glasses. What exactly are accommodative disorders and how can they be corrected?
Accommodating the eye - what is it?
Accommodating the eye, also known as adjusting the eye, involves adjusting the eye to view objects at different distances. The process is made possible by a change in the shape of the lens, occurring as a result of the contraction of the ciliary muscle.
One of the features of the lens is its flexibility. When the ciliary muscle contracts, the lens takes on a more spherical shape, allowing sharp vision of objects at close range. Diastasis, on the other hand, has the opposite effect - it flattens the lens and allows sharp vision of objects far away.
Range and amplitude of accommodation
When determining the work of accommodation and diagnosing its disorders, the range of accommodation and the amplitude of accommodation are taken into account, among other things.
The eye's range of accommodation is measured as the distance between the near and far points:
- Point of visual proximity - the closest point that the eye can see sharply due to accommodation,
- Visual distance point - the farthest point, the image of which is formed on the retina when accommodation is turned off.
Accommodative amplitude is the largest possible change in the value of the lens. In this case, the closest point for which the eye forms a sharp image due to accommodation is referred to as the near point. The farthest point for which the eye is able to produce a sharp image on the retina is the far point of the eye.
What is the basis of accommodative disorders?
Accommodative disorders are associated with a decrease in lens elasticity, which patients usually experience after 40. year of age. This process - called presbyopia - continues until the age of sixty to seventy, which is when the eye completely loses its ability to accommodate.
Accommodative shrinkage
However, ocular attitudinal disorders do not only occur in seniors - they also affect younger people. One of the causes is accommodative spasm - a situation during which the accommodative reflex does not run properly - the response is too strong in relation to the stimulus. The ciliary muscle then contracts excessively, and the constant, excessive accommodative tension causes a problem with its relaxation. The patient looking into the distance then sees blurry.
Accommodative spasm occurs most often in patients with uncorrected hyperopia, but also in people who observe objects at close range for long periods of time - such as a computer monitor or phone display. The second group, unfortunately, includes an increasing number of children and adolescents.
Other causes of accommodative spasm include muscle paralysis, neurological disorders, certain ophthalmic diseases such as iritis, general diseases, and taking certain medications.
Weakened accommodation of the eye
Another problem may be impaired accommodation of the eye. It is a disorder in which a distinction is made:
- Accommodative malfunction - difficulty in quickly sharpening the image when flipping vision from far to near, despite correct amplitude,
- Insufficient accommodation - reduced efficiency and amplitude of accommodation,
- Accommodative fatigue - rapid eye fatigue and worse vision during prolonged close work,
- accommodative severity - a delayed accommodative response,
- Accommodative paralysis - lack of accommodative response.
How are accommodative disorders treated?
Abnormal accommodations associated with presbyopia can be corrected in several ways. They are:
- Wearing glasses - if the patient has previously been diagnosed with a vision defect, he or she may opt for progressive glasses. The upper area of the lens allows you to see objects far away, the lower area gives you a sharp view of intermediate distances, while the lower area is used for reading and looking at objects less than half a meter away. Progressive eyeglasses can have lenses that correct the defect. That way you don't have to use one pair for reading and another for wearing during the day.
- Use of contact lenses - multifocal lenses are highly effective, allowing both near and far vision.
- Surgery - this involves removing the natural lens and replacing it with an artificial multifocal lens.
- Laser vision correction - a popular and effective procedure, during which the cornea is reshaped so that the patient can see well up close and far away without having to wear glasses. Patients from Malopolska are welcome to visit our eye clinic in Krakow - Voigt Klinika Oka.
With accommodative spasm, treatment should address the cause of the problem to rule out possible diseases. It is important to implement healthy habits: breaks at work, less time spent in front of the computer, more outdoor exercise. Also helpful is therapy with Hart boards - special exercise boards and flippers - 2 pairs of spherical lenses - negative and positive, to help relax and tighten the ciliary muscle.