Hyperopia (hypermetropia) is a refractive disorder in which images of objects focus not on the retina, but in the plane located behind it. With farsightedness, the ability to distinguish objects in the vicinity significantly worsens. In addition, hyperopia is accompanied by increased visual fatigue, headaches, burning in the eyes; high degrees of hypermetropia – poor distant vision. Examination for hyperopia includes the definition of visual acuity, refractometry, ophthalmoscopy, skiascopy, biomicroscopy, ultrasound of the eyeball. The treatment of hyperopia depends on the degree of refractive error and may consist in optical correction, the use of hardware methods (video computer correction, laser stimulation), laser correction (LASIK, thermokeratoplasty), thermokeratocoagulation, hyperfacia, hyperartifacia, etc.
The prevalence of hyperopia among adults over the age of 18 is about 35-45%. Hypermetropic refraction is physiological in children under the age of 7-12 years: it occurs in 90% of children under 3 years and 35% of children aged 13-14 years. Farsightedness is characterized by a weakness of refraction, which requires a strain of accommodation even with distant vision. With farsightedness, the light rays perceived by the eye converge in focus behind the retina. Therefore, the hypermetrope sees the image of the object in a fuzzy, slightly blurred form.
The scientific name of hyperopia – hypermetropia, adopted in ophthalmology, comes from the Greek words hyper – “over”, metron – “measure” and ops – “eye”.
As in the case of nearsightedness (myopia), with farsightedness, there is a discrepancy between the strength of the refractive apparatus and the anterior-posterior size of the eye. However, with farsightedness, this occurs either due to the relative weakness of the refractive apparatus of the eye, or the shortened anterior-posterior axis (FRA) of the eyeball. Both of these mechanisms can cause the refracted rays to focus at a point behind the retinal plane. In some hypermetropics, the insufficient optical power of the cornea and lens is combined with a shortened longitudinal axis of the eyeball.
Physiological hyperopia (+2+4 dpt) is characteristic of newborns and is explained by the small longitudinal size of the eyeball (length FRA = 16-17 mm). Hyperopia 4 dptr characterizes the maturity of the fetus; an increase in the degree of hypermetropia is usually observed with microphthalmia and is combined with other congenital eye anomalies (cataracts, colobomas of the OND and vascular membrane, aniridia, lenticonus, predisposition to glaucoma, etc.), as well as other malformations (cleft lip, cleft palate, anomalies of the fingers and toes, ears, etc.).
As the child grows, the size of the eyeball also increases to normal (FRA = 23-25 mm), which in most cases leads to the disappearance of hyperopia by the age of 12 and the formation of proportionate refraction (emmetropia). With the progression of the growth of the eye, myopia develops, with a delay in its growth, farsightedness develops. By the time the growth of the organism is completed, farsightedness is noted in 50% of people, the remaining half has emmetropia and myopia.
Why there is a lag in the growth of the eyeball is unknown. Nevertheless, most farsighted people up to 35-40 years old manage to fully compensate for the weakness of refraction by constant tension of the ciliary muscle of the eye, which allows the lens to be held in a convex state, thereby increasing its refractive ability. However, in the future, there is a decrease in the ability to accommodate, and by about 60 years of age, compensatory capabilities are completely exhausted, which leads to a steady decrease in visual clarity both in the distance and near. Thus, the so-called senile hyperopia, or presbyopia, develops. Restoration of vision in this case is possible only with the help of constant use of glasses with collecting lenses, therefore farsightedness is usually denoted in positive diopters.
In addition, farsightedness is characterized by aphakia – a congenital or acquired condition in which there is no lens. Most often, aphakia is associated with the removal of the lens during cataract extraction or injuries (dislocation of the lens). With aphakia, the refractive power of the eye is significantly reduced, visual acuity is about 0.1 and requires substitution correction with strong positive lenses or implantation of an intraocular lens.
Depending on the mechanism of hypermetropia development, axial or axial hyperopia is distinguished, associated with a shortened FRA of the eyeball, and refractive, due to a decrease in the refractive power of the optical apparatus.
In the event that the existing refractive error is compensated by the accommodation voltage, they speak of latent hyperopia; if self-correction is impossible and the need to use convex lenses, hypermetropia is regarded as obvious. With age, latent farsightedness, as a rule, turns into explicit.
Depending on the age, there are natural physiological hyperopia in children, congenital hyperopia (with congenital weakness of refraction), age-related hyperopia (presbyopia).
According to the degree of required correction in diopters and on the basis of refractometry data, farsightedness is divided into three degrees:
- weak – up to +2 dpt
- average – up to +5 dpt
- high – over +5 dptr
Weak degrees of hyperopia at a young age occur without any symptoms: due to the tension of accommodation, good vision is preserved both near and far. With moderate hyperopia, long-range vision is practically not impaired, however, while working at close range, there is rapid eye fatigue, pain in the eyeballs, in the area of the brow, forehead, bridge of the nose, visual discomfort, a feeling of blurring or merging of lines and letters, the need to distance the object under consideration from the eyes and brighter workplace lighting. High degrees of hyperopia are accompanied by a pronounced decrease in vision near and far, asthenopic symptoms (a feeling of bursting and “sand” in the eyes, headache, rapid visual fatigue). With hyperopia of medium and high degrees, changes in the fundus are revealed – hyperemia and fuzzy boundaries of the eye.
Children with congenital uncorrected farsightedness over +3 dptr have a high probability of developing friendly (convergent) strabismus. This is facilitated by the need for constant tension of the oculomotor muscles and the reduction of the eyes to the nose in order to achieve greater clarity of vision. As farsightedness and strabismus progress, amblyopia may develop.
With hyperopia, recurrent blepharitis, conjunctivitis, barley, chalazion often occur, since patients involuntarily rub their eyes, thereby bringing infection. In older people, hyperopia is one of the factors contributing to the development of glaucoma.
Usually farsightedness is detected by an ophthalmologist during a visual acuity check. Visometry in hypermetropia is performed without correction and using trial plus lenses (refraction test).
Diagnosis of hyperopia involves a mandatory refraction study (skiascopy, computer refractometry). To detect latent hyperopia in children and young patients, refractometry is recommended under conditions of induced cycloplegia and mydriasis (after instillation of atropine sulfate into the eyes).
In order to determine the anterior-posterior axis of the eyeball, an ultrasound of the eye and echobiometry are performed. To identify concomitant hyperopia pathology, perimetry, ophthalmoscopy, biomicroscopy with a Goldman lens, gonioscopy, tonometry, etc. are performed. In case of strabismus, biometric studies of the eye are performed.
Methods of treating hyperopia are combined into conservative (glasses or contact correction), laser (LASIK, SUPER LASIK, LASEK, EPI-LASIK, FRK, Femto LASIK) and surgical (lensectomy, hyperfacia, hyperartifacia, thermokeratoplasty, etc.). The main conditions for the correction of hypermetropia are timeliness and adequacy.
In the absence of asthenopic complaints, visual acuity of both eyes of at least 1.0 and stable binocular vision, correction is not indicated.
The main way to correct children’s hyperopia is the selection of glasses. Preschool children with hyperopia of more than +3 dpt need glasses for permanent wearing. If there is no tendency to develop strabismus and amblyopia by the age of 6-7, the eyeglass correction is canceled. With asthenopia, “plus” glasses or corrective contact lenses are selected, taking into account individual data and concomitant diseases. In some cases, with hypermetropia up to +3 dpt, night orthokeratological lenses are used. With high degrees of farsightedness, complex glasses or two pairs of glasses can be issued (for working at close and long distances).
With farsightedness, it is recommended course hardware treatment (Amblyocore, Amblyotrener, Synoptophore, software-computer treatment, “Trickle”, etc.), physiotherapy (massage of the neck-collar zone, laser therapy, magnetotherapy, etc.), courses of vitamin therapy and dietary supplements. When watching TV, it is advisable to use perforated glasses that reduce the stress of accommodation.
From the age of 18, it is possible to carry out laser correction of hyperopia up to +6 dptr. The most popular laser techniques are LASIK, LASEK, IntraLASIK, Super LASIK, EPI-LASIK, photorefractive keratectomy (PRK). Each of the methods of laser correction of hyperopia has its own indications, but their essence is the same – the formation of the corneal surface with individual parameters. Excimer laser correction of hyperopia is non-traumatic, which eliminates complications from the cornea and minimizes the likelihood of astigmatism.
In farsightedness surgery, the method of refractive lens replacement is used: in this case, the eye’s own lens is removed (lensectomy) and replaced with an intraocular lens of the required optical strength (hyperartifacia). Refractive lens replacement is also used for age-related hyperopia.
Surgical treatment of hyperopia may also consist of hyperfacia (implantation of a positive phakic lens), thermokeratocoagulation, laser thermokeratoplasty, keratoplasty (corneal plasty).
Prognosis and prevention
Complications of uncorrected hyperopia can be strabismus, amblyopia, recurrent inflammatory eye diseases (conjunctivitis, blepharitis, keratitis), glaucoma. Patients with hyperopia are recommended to visit an ophthalmologist at least 2 times a year.
When detecting hyperopia, it is necessary to strictly follow the prescribed recommendations, observe the correct visual regime (using sufficient lighting, performing gymnastics for the eyes, alternating visual work with active recreation). The same recommendations can be attributed to the prevention of hyperopia. In order to prevent the development of strabismus, ophthalmological examinations of children from 1-2 months, 1 year, 3 years and 6-7 years are carried out.