Long sighted

Introduction to hyperopia The resting state of the eye forms a focal point behind the retina of the parallel light, called hypermetropia (hyperopia). The optical focus of this kind of eye is behind the retina, so the image formed on the retina is ambiguous. In order to see distant objects, the focus of the retina is moved to the retina by adjusting the force. Therefore, the farsighted eye is often in the eye. Adjusting the state is prone to eye fatigue. If vision is normal and there are no symptoms, no treatment is needed. If visual fatigue or vision has been affected, wear a suitable lenticular lens correction. Children with a high degree of hyperopia, especially those with esotropia should have an early prescription. As the eyeball develops, the degree of farsightedness of children gradually declines, so it is necessary to check once a year to adjust the degree of wearing glasses at any time. In addition to wearing a convex mirror correction, it can also be corrected with a contact lens. basic knowledge The proportion of illness: 0.02% Susceptible people: no special people Mode of infection: non-infectious Complications: headache, nausea and vomiting

Presbyopia

Axial hyperopia (30%):

That is, the anterior-posterior axis of the eye is shorter than the emmetropia. This is one of the most common types of refractive errors. The average eye axis of a person at birth is about 17.3 mm. From the perspective of the length of the eye axis, it is almost hyperopia. It is said that the baby's hyperopia is physiological. After that, 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 axis of the eye can not reach the length of the normal eye. Therefore, the adult's eye axis length is maintained in adulthood, which is called axial hyperopia, and vice versa. In the case of myopia, a true vision with zero true diopter is a minority.

In general, the degree of short-sightedness of the human eye is not very large, rarely exceeding 2 mm. According to the optical calculation of the eye, every 1 mm shortens, which represents a change of 3D. Therefore, hyperopia beyond 6D is rare, but also has a height. Hyperopia, and some eyes, although not combined with any other pathological changes, can be as high as 24D, such as small eyeballs, and their farsightedness will even exceed 24D.

The front and rear axes of the eye become shorter (25%):

It can also be seen in pathological conditions. The inflammatory mass of the eye tumor or the eyelid can cause the posterior pole of the eyeball to invade and flatten it; in addition, the new organism or the pelvic tissue edema after the ball can move the macular area of the retina forward; A more serious situation can be caused by retinal detachment, and the displacement caused by such detachment can even make it touch the back of the crystal, and the change of diopter is more obvious.

Another cause of hyperopia is curvature hyperopia, which is formed by the small curvature of any refractive body in the refractive system of the eye, called curvature hyperopia, where the cornea is prone to such changes, such as innate Oral flat membrane, or caused by trauma or by corneal disease, from optical theoretical calculations, every 1mm increase in the curvature radius of the cornea can increase 6D hyperopia, in this curvature of hyperopia, only a few corneas can remain completely spherical Almost all have astigmatism.

Refractive hyperopia (25%):

This is due to the diminished refractive power of the crystal, which is caused by the physiological changes that occur in old age and the pathological changes caused by the treatment of diabetics. When the crystal is dislocated, it can also produce hyperopia, which may be congenital. Irrespective or caused by eye trauma and eye disease; in addition, high vision can be caused when the lens is lacking.

Optical state of hyperopia (5%):

Whether the distance of the eyesight is shortened due to the shortening of the length of the eye axis, the curvature of the refractive body is reduced, or the refractive power is reduced, the optical effect is the same, that is, the parallel light emitted from infinity is behind the retina. The focus is formed, and the ambiguous image is formed on the retina. Since the axis of the eye is shortened, the corresponding retina is approached to the node, and the resulting image is smaller than the emmetropia, which is emitted at the macula of the retina of the emmetropic eye. The light, through the refraction of the eye, the light is parallel. It can also be said that the macula of the emmetropic eye becomes the conjugate focal point with infinity. Therefore, when the eye is infinity, no adjustment is used, and the hyperopia is emitted by the macula. The light is scattered, the yaw focus of the eye is behind the eyeball, so it is a virtual focus, because there is no collection light in the universe, so when the eye is at rest, it is unclear to see any body. There are two ways to make the light into a collection: the first is to adjust the eye itself, and the second is to wear a convex lens.

(1) emmetropia: parallel light focuses on the retina; (2) hyperopic: parallel light gathers behind the retina; (3) hyperopic: due to the use of the lens to adjust the parallel light to focus on the retina; (4) hyperopic: the convex lens placed in front of the eye Instead of adjusting, the retina on the parallel light can also be focused.

AB is an object; N is a node; ab is an inverted image of the retina of light passing through A and B through N; H is a far vision, E is a front view, M is a myopia; 3>2>1.

Presbyopia adjustment (5%):

Adjustment is the result of the gradual evolution of the eye in order to see the near or see the fine body. The front view is in a resting state. When looking at a distant object, a clear image is formed on the retina. When the near eye is seen, the light entering the eyeball is scattered, and Imaging behind the retina, so the image formed on the retina is ambiguous, this ambiguous image, forming a visual-dynamic stimulus in the visual center, causing the ciliary muscle, which is dominated by the third pair of cranial nerves, pupil The sphincter and the medial rectus muscle produce excitement, form a joint movement of regulation, assembly and contraction, called near-reflex, between which the regulation is the main, the anterior-posterior axis of the eyeball is short or the eye is refraction The system's refractive power is weak, and the light emitted from infinity is also imaged behind the retina, so the image on the retina is also blurred. This blurred image also forms a visual-dynamic factor in the visual center, just like the right eye. Produce a similar approximation to the near-sightedness of the right-looking eye, moving the image forward, forming a clear image on the retina, and we see the near-field adjustment of the positive field of view, called physiological regulation; hyperopia Seeing the adjustments used in the near future, called non-physiological adjustment, far-sighted eyes should be used to adjust any object in the outside world, so the adjustment is closely related to the hyperopic eye, so according to the difference in the effect caused by the adjustment on hyperopia, the hyperopic eye can be divided into There are two types of recessive hyperopia and dominant hyperopia. Among them, dominant hyperopia is divided into corrective hyperopia and absolute hyperopia.

Generally speaking, the eyeball of the presbyopic eye is small, and the eyeball becomes smaller not only in the anterior-posterior axis of the eye, but in all the axial directions, the cornea in the hyperopic eye is also small, due to the change in shape of the crystal. Not big, compared with the reduced eyeball, the crystal is relatively large, so the anterior chamber becomes shallow, making this eye prone to glaucoma, which should be paid attention to when using mydriatic medicine, high hyperopia can form development Deformation, such as small eyeballs, small eyeballs are not necessarily hyperopic eyes, mainly depends on the matching between the anterior and posterior axes of the eyeball and the refractive system of the eyeball. When the eyeball becomes smaller, the refractive power of the refractive system of the eyeball increases. It does not necessarily become farsighted.

Fundus examination can see the typical hyperopic retina, which is characterized by special brilliance, which is caused by reflection, called the retinal flash ring; the optic disc forms a special performance, much like optic discitis, so it is called pseudo-optic disc. Inflammation, the optic disc is dark red, the edges are slightly smeared and irregular, and outside the blurred area, sometimes surrounded by gray halos, or surrounded by stripes radiating from the edge to the surrounding, making it more blurred, often below the optic disc Forming a new form of change, which is generally considered to be congenital, and thus does not cause a significant reduction in visual acuity. In addition to the enhanced vascular reflex, it can also be seen that the blood vessels are improperly bent and abnormal branches. Changes in the eye should be carefully observed to avoid misdiagnosis. When a hyperopic eye occurs in a single eye, the ipsilateral face tends to develop poorly and becomes asymmetrical on both sides. The developmental asymmetry is often seen in the eye itself. This hyperopia Most of the eyes are combined with astigmatism.

Presbyopia prevention

So far, although there is no exact way to prevent presbyopia, the following methods have certain benefits for the eyes of patients with hyperopia:

(1) Eat foods rich in vitamin A and vitamin C.

(2) Wear sunglasses when working outdoors or walking to prevent excessive UV rays from illuminating the eye.

(3) Drink enough water to prevent dry eyes.

(4) Protect your eyes when doing dangerous work, such as knocking on metal objects and using corrosive chemicals.

(5) Regular routine eye examinations.

Hyperopia complications Complications, headache, nausea and vomiting

Working for a long time at close range, over-regulation can cause visual fatigue, and its symptoms are visual sensation, eyebrow bow pain, eye pain, and even nausea and vomiting. Visual fatigue is the most common complication of presbyopia and can be accompanied by headaches, dizziness and physical and mental discomfort. If the fatigue persists for too long, sometimes a short period of ciliary muscle paralysis may occur, resulting in a high degree of visual impairment.

Hyperopia symptoms Common symptoms Vision-related eyeball function reduction... Visual impairment Fatigue, dizziness, strabismus, weak paralysis

Vision: adolescents with low-level hyperopia, far and near vision can be normal; moderate hyperopia, some have far vision, and poor nearsightedness, or near and far vision; high hyperopia, far and near vision are poor, and old The phenomenon appears earlier.

Eye fatigue: Because the farsighted person needs to adjust when looking far and looking close, the eye fatigue is obvious, and the reading or close working time cannot be sustained. The eyeball with high hyperopia is small, the anterior chamber can be shallower than normal, and the optic papilla is small, which can be pseudo-optic papillitis.

Strabismus and amblyopia: Excessive adjustment can cause excessive collection, so it is easy to cause implicit or co-rotation. Amblyopia can also occur if the anisometropia is obvious or the degree of farsightedness is high.

Presbyopia examination

(1) Eye appearance examination under diffused light

Including the size of the eyeball, and the symmetry of the dangerous shape, some patients may be implicit or oblique, which is more common in preschool children, and a small number of patients also have exotropia. The covering method can be judged to be recessive or dominant.

(2) Vision examination

The correct examination and flexible analysis of far and near vision are very helpful for the rapid diagnosis of hyperopia. The eyes of adolescents have a strong regulation effect. When mild hyperopia, far and near vision can be normal; adolescents with high hyperopia and middle age People with moderate hyperopia, far, near vision decreased.

(3) ophthalmoscopy

The most common manifestation is that the papillary head is small, the color is ruddy, the edge is slightly blurred, and the hyperopic hyperopia can be combined with a yellowish-yellow choroidal sputum. The larger one can have a visual field defect, and a new moon is formed below the nipple. The change in shape, which is generally considered to be congenital, does not cause a significant reduction in vision. Relatively speaking, the macular portion of the hyperopic eye is farther away from the nipple than the emmetropic eye.

(4) Subjective optometry examination and objective retinoscopy examination, and combined with ball and column mirror to correct.

In addition, conditional can also be used for anterior chamber angle inspection, the anterior chamber angle is often slightly shallow.

Presbyopia diagnosis

diagnosis

It can be diagnosed according to symptoms and examinations.

Differential diagnosis

Need to be differentiated from presbyopia.

Presbyopia: The near vision is unclear, but the distance is normal, the anteroposterior diameter of the eyeball and all parts are normal and farsighted.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.