farsighted
Introduction
Introduction to hyperopia Hyperopia is a parallel light that forms a focus behind the retina after it enters the eye. External objects cannot form a clear image in the retina. The subjective feeling of the patient is far from blurred, and the nearer is more blurred. Use a convex lens to correct hyperopia. Mild hyperopia, through the adjustment of the crystal, the subjective feeling is not obvious. As the age increases, the adjustment power decreases, and the symptoms such as visual fatigue and blurred vision gradually manifest. basic knowledge The proportion of illness: 10% Susceptible people: no special people Mode of infection: non-infectious Complications: glaucoma
Cause
Telepathy
Axial hyperopia (35%):
The anterior-posterior axis of the eye is shorter than the emmetropic eye. It is one of the most common types of refractive errors in the eye. At birth, the average axis of the human eye is about 17.3 mm. From the perspective of the length of the eye axis, it is almost all hyperopia. Therefore, the baby's hyperopia is physiological. Later, as the baby's body develops, the anterior-posterior axis of the eye also grows slowly. When it reaches adulthood, the human eye should be square or close to face, some people in the development of the eye. Due to the influence of internal (genetic) and external environment, the eyeball stops developing, and the axial length of the eyeball can not reach the length of the emmetropic eye. Therefore, when the adult is still in the infant or young child, the axial axis is long, which is called the axial hypermetropia. Overdevelopment is the myopia, and the emmetropia is the transitional phase of the two. The eye with zero true diopter is very few.
Curvature hyperopia (30%):
It is formed by the small curvature of any refractive body in the eye refractive system. It is called curvature hypermetropia. The cornea is the part that is prone to such changes. It may be congenital flat cornea. It can also be caused by trauma or corneal disease. From the optical theoretical calculation, every 1mm increase in the curvature radius of the cornea can produce 6.0D hyperopia. In this curvature hyperopia, only a few corneas can remain completely spherical, almost all merged. Different degrees of astigmatism.
Exponential hyperopia (20%):
This is due to the diminished refractive power of the lens, which is caused by the physiological changes that occur in old age and the pathological changes caused by the treatment of diabetics. Furthermore, the posterior dislocation of the lens can also produce hyperopia. May be congenital abnormalities, caused by ocular trauma or eye disease; in addition, due to lack of lens can also cause hyperopia.
Pathogenesis
Whether the distance is due to the shortening of the length of the eye axis, the curvature of the surface of the refractive body is reduced, or the optical effect is the same due to the decrease of the refractive power, that is, the parallel light emitted from infinity is in the retina. The rear forms a focus, and the blurred image is formed on the retina. As the axial length becomes shorter, the corresponding retina approaches the node, and the resulting image is smaller than the emmetropic eye. In the hyperopic eye, the macula is located. The emitted light exits the eyeball in a diffuse manner through the eye, and extends backward in the opposite direction of the diffused light to form a virtual focus behind the eyeball. Since there is no collected light in the universe, the eye is not used for adjustment. When looking at any object, it is not clear. There are only two methods for the human eye to make the light into a collection. The first is to adjust the eye itself, and the second is to wear a convex lens.
Prevention
Hyperopia prevention
The visual acuity of the hyperopic eye may be due to the depth of the degree of hyperopia and the age, the near vision, the far vision is poor or the near vision is poor, the distance vision is good, or the distance between the near and far vision is poor. Hyperopia is prone to visual fatigue, close working or reading time is not durable, should be optometry, and then with a suitable convex spherical lens can be solved. For adolescents with farsightedness and an internal oblique, it is necessary to drop the ciliary muscle dilated optometry. Any child who finds strabismus should come to the hospital for examination as soon as possible. Dilated optometry and wearing appropriate glasses will help improve vision, correct partial strabismus and prevent amblyopia.
Complication
Hyperopia complications Complications glaucoma
Small eyeballs, small cornea, shallow anterior chamber and glaucoma.
Symptom
Hyperopia symptoms Common symptoms Lens dislocation or subluxation Visual obscuration to see things become farsightedness can not last long-term visual impairment Eye dryness, soreness, fatigue, weakness, tears, migraine, nausea
1. Vision and visual impairment
(1) The naked eye vision of presbyopia:
The visual acuity of hyperopia is closely related to the degree of hyperopia. Mild hyperopia can be compensated by the adjustment without loss of vision. However, if hyperopia is not compensated by regulation, it becomes absolute hyperopia, often causing different degrees. The vision is reduced.
The degree of hyperopia and the visual acuity of the naked eye are closely related, and the strength of the adjustment force is also closely related to the visual acuity of the naked eye. Not only mild, ie, moderate hyperopia, such as its strong regulatory function, it can often be adjusted. Correcting its farsightedness, it can be seen clearly with other external targets. Such eye-seeing and emmetropic eyes are no different. Therefore, it is said that this is far from being a false positive vision. Clinically, because of the neglect of refractive error examination, hyperopia is often missed. And adolescents have mild hyperopia, because their adjustment is very strong, far, near vision can be normal, but in middle-aged people due to weakening of regulation, even if far vision is still good, near-vision goals may also be difficult, in the middle Hyperopia, younger people have strong adjustment, far vision may be better, but near vision is more difficult; older people have insufficient adjustment, their distance, nearsightedness must be reduced, high farsightedness, not only the near vision is not good, far Vision is also often a significant obstacle. Patients with a high degree of hyperopia prefer to take the target very close to the front, and use the pupil to shrink and enlarge the retina image to increase the ability to see the target. Hyperopia when children often mistaken for high myopia, and to the eye with myopia required, so care must be taken to check.
(2) Corrective vision of presbyopia:
Visual impairment caused by hyperopia is more common, especially with the increase of age, the adjustment power is gradually decreasing, and the recessive hyperopia is gradually transformed into dominant hyperopia. Thus, not only the distance vision is reduced, but also the near vision is more likely to be disordered. Therefore, It is important that the lens corrects hyperopia to improve visual acuity.
2. Visual fatigue and systemic symptoms
(1) Visual fatigue:
Because hyperopia has to use the adjustment function whether it is far or near, it is easy to produce visual fatigue when reading books or other near-sighted work, except for the small degree of farsightedness and the light age. , blurred vision, heavy eyeballs, pressure, or soreness, or deep pain in the eyeball, or different degrees of headache, the eye is prone to conjunctival congestion and tearing, the headache is mostly in the forehead or upper part of the ankle, sometimes causing shoulder blades Department discomfort, migraine, or even nausea, vomiting and other symptoms, these symptoms are caused by the use of regulation, it is called regulatory visual fatigue, such as the characteristics of visual fatigue is: such as closed eyes rested with eyes or put on After a suitable convex lens, the symptoms can disappear or be significantly reduced; however, if you continue to read or write, such as near-eye, the same visual fatigue will occur.
(2) systemic symptoms:
In addition to causing regulatory visual fatigue, hyperopic eyes sometimes cause systemic symptoms, especially changes in the nervous system. Therefore, patients with ophthalmology should be treated with systemic symptoms such as neurasthenia or autonomic dysfunction, and ophthalmologists should do their refractive status. Careful examination, if found to have hyperopic refractive error, should be given appropriate glasses correction.
3. Adjustment and collection linkage misalignment
When a far-sighted patient looks at a distant target, the two eyes must be parallel, that is, they do not need to be assembled, but must be adjusted; when the two eyes are close to the target, the adjustments used are often larger than the set, resulting in an imbalance between the adjustment and the set linkage relationship. Become a recessive slant, and a severe squint appears. For example, a 4.OD hyperopic patient, when looking at an infinity target, the two eyes must be parallel, that is, no aggregation is needed, but in order to see the distant target, It is necessary to correct the hyperopia and use the 4.0D adjustment force. If the viewing distance is changed to 33cm, then the adjustment force of 3.0D must be used again, that is, the adjustment force of 7.0D must be used, but only used at this time. The collection of 3.0m angles, such adjustment and separation of the collection, makes the two eyes almost impossible. At this time, if the patient adjusts to determine his collective force, he will gather the fixation point to the front 14cm, but the target At 33cm, it is difficult to see clearly. If the adjustment is determined according to the collective force, only the 3.0D adjustment force is used instead of the 7.0D adjustment force, so the target is also unsightly. Therefore, such a patient has to give up the two-eye single vision. With only one glance, the other eye turned to the inside and became an esotropia.
4. Changes in the anterior and fundus of presbyopia
The anterior and fundus changes of the hyperopic eye exist in a higher degree of hyperopia. Usually, the eyeball is relatively small, the appearance of the eyeball is slightly concave, the anterior chamber is shallow, and the pupil is small. The hyperopia is often adjusted for tension and conjunctival congestion. In patients with chronic conjunctivitis, mumps and blepharitis, the hyperopic eye has a large Alpha angle, and the visual axis is often on the nasal side of the optical axis, so the appearance is pseudo-external strabismus.
Moderate and high presbyopia, often have varying degrees of fundus changes, more common is pseudo optic neuritis, a few severe cases can be pseudo-optic optic edema, pseudo-optic neuritis is typical: the disc is red and dark, the border is not Clearly, the physiological depression is light or disappearing, the shape of the nipple is not neat, and the retina around the optic disc can be seen with special silk-like reflex. The artery can be characterized as vascular sclerosis, varicose vein expansion or abnormal blood vessel branch, so it must be true or Optic disc edema differentiation, pseudo-refractive venous congestion, no leakage during fluorescein angiography and retinal hemorrhage or exudation, etc., pay attention to eye vision, visual field and refractive examination, usually not difficult to identify.
Examine
Hyperopia examination
No special laboratory tests.
1. Ultrasound examination: B-ultrasound is used to measure the length of the axon, the depth of the anterior chamber, and the thickness of the lens.
2. Computer optometry and retinoscopy: need to be carried out in full ciliary muscle paralysis, especially for adolescents.
Diagnosis
Hyperopia diagnosis
diagnosis
According to the naked eye, near vision and test results, the detection of hyperopia is not difficult.
Differential diagnosis
1. Myopia: adolescents with mild hyperopia, due to excessive reading and writing, such as reading, writing, etc., sometimes cause abnormal contraction of the ciliary muscles and paralysis, leading to the occurrence of pseudo-myopia, at this time the distance vision is reduced, the lens is enhanced with concave lens, with convex lens In contrast, the visual acuity is reduced. Therefore, the hyperopia is mistaken for myopia, and it is accompanied by myopia. However, due to the accidental wearing of the concave lens, the adjustment of the sputum is deepened, and more obvious visual fatigue occurs. Therefore, the patient's vision should be paid attention to during the examination. (far, near) and refractive status are variable, retinoscopy, etc. If there is doubt, check the near point distance, use the cloud method or atropine to fully paralyze the ciliary muscles, and remove the sputum, the pseudo myopia can be eliminated. Restore the original appearance of farsightedness.
2. Presbyopia: Hyperopia and presbyopia are two different refractive states, but because they are corrected with convex lenses, far vision is good, both are often confused, hyperopia is a kind of refractive error, can be seen after wearing a convex lens Qingyuan side can also see the near side, and the old-fashioned only because of the weakening of the adjustment power, the near-target is not clear, of course, it is a physiological obstacle. Although the convex lens can be seen, the near-target can be seen. , newspaper), but can not use this mirror to see distant objects at the same time, which is different from the situation of the farsighted wearing glasses.
3. Orthopaedic: Mild or moderately hyperopic eyes with strong adjustment ability can correct their hyperopia by adjusting themselves. It can be seen clearly for both distant and near targets. It is similar to the appearance of the person, so it is called false. In order to identify the farsightedness and the front view, in addition to the easy to distinguish with the reconnaissance method, the easiest and correct way is to use a mild (+0.5D) convex lens placed in front of the eye to be inspected, such as the reduction of vision after the addition of the mirror, may be Face up, if the vision rises or remains the same, it is the evidence of hyperopia, combined with the reconnaissance is easy to identify.
