Presbiopiya – the age decrease in akkomodativny ability of an eye connected with natural process of aging of a crystalline lens. Presbiopiya is shown by deterioration in ability to see at a short distance: blurring and illegibility of sight close, astenopichesky symptoms (headaches, fatigue of eyes, bad general health). Diagnostics of a presbiopiya includes sight check, assessment of a refraction and accommodation, carrying out an oftalmoskopiya. Treatment of a presbiopiya can consist in selection of necessary points, laser correction of sight (LASIK, FRK), refraction replacement of a crystalline lens (lensektomiya).
Presbiopiya or senile far-sightedness is the inevitable process connected with natural aging of an eye. It is known that at normally refraction (emmetropiya) the presbiopiya develops at the age of 40-45 years, at far-sightedness – slightly earlier, and at short-sightedness – later. With age there are accommodations progressing decrease that leads to gradual loss of ability of an organ of vision to be focused on nearby objects. According to ophthalmology, the presbiopiya occurs at 25-30% of the population.
Presbiopiya are the cornerstone the natural involutional processes happening in an organ of vision and leading to physiological weakening of accommodation. Development of a presbiopiya – inevitable age process: so, by 30 years akkomodativny ability of an eye decreases half, by 40 years – on two thirds, and to 60 – is almost completely lost.
Accommodation is an ability of an eye to adapt to vision of the objects located at various distance. The Akkomodativny mechanism is provided due to property of a crystalline lens to change the refracting force depending on degree of remoteness of a subject and to focus its image on a retina.
The sclerous changes of a crystalline lens () which are characterized by its dehydration, consolidation of the capsule and a kernel, elasticity loss act as the main pathogenetic link of a presbiopiya. Besides, also adaptive opportunities and other structures of an eye are lost with age. In particular, dystrophic changes in the ciliary (tsiliarny) muscle of an eye holding a crystalline lens develop. Dystrophy of a ciliary muscle is expressed by the termination of formation of new muscle fibers, their replacement with connecting fabric that leads to easing of its sokratitelny ability.
As a result of these changes the crystalline lens loses ability to increase in radius of curvature by consideration of the objects located close to an eye. At a presbiopiya the point of clear vision gradually moves away from an eye that is shown by difficulty of performance of any work close.
Age changes of the optical apparatus of an eye are connected with a metabolic disorder through vessels of a retina and a conjunctiva develop at the people having diabetes, atherosclerosis, arterial hypertension, hypovitaminosis, chronic intoxications quicker (nicotinic, alcoholic). Earlier development of a presbiopiya is promoted by a gipermetropiya, an astigmatism, frequent inflammations of eyes (conjunctivitis, uveita, blefarita, keratita), eye operations, eye injuries, and also the professional activity connected with intense and long visual loading at a short distance (laboratory assistants, engravers, programmers, etc.). In turn, the presbiopiya which early arose is risk factor of development of glaucoma.
At people with an emmetropiya the first signs of a presbiopiya develop at the age of 40-45 years. During the work at a short distance (the letter, reading, sewing, occupations with fine details) there comes the bystry visual exhaustion (an akkomodativny asthenopia): fatigue of eyes, headaches, dull ache in eyeballs, a nose bridge and frontal bones, dacryagogue and an easy photophobia. At a presbiopiya the objects located close become indistinct, indistinct that is shown by desire to remove an object of occupations far away from eyes, to include brighter lighting.
Subjective manifestations of a presbiopiya develop when the closest point of accurate sight moves away from an eye on 30-33 cm, i.e. on average after 40 years. Changes of accommodation progress up to 65 years – approximately at this age the closest point of accurate vision moves away on the same distance where there is a further point. Thus, accommodation becomes equal to zero.
Presbiopiya at gipermetrop (persons with far-sightedness) is shown, as a rule, earlier - at the age of 30-35 years. At the same time not only sight close, but also afar worsens. Thus, far-sightedness not only promotes early development of a presbiopiya, but also strengthens it.
With short-sightedness (miopiy) the presbiopiya can remain unnoticed with people. So, at small degrees of short-sightedness (-1-2 ) age loss of accommodation the long time is offset in this connection manifestations of a presbiopiya develop later. Persons with a miopiya-3-5 often do not need sight correction close at all: in this case it is rather simple to them to take off glasses in which they look afar.
If manifestations of a presbiopiya come to light before 40 years, the careful inspection at the ophthalmologist directed to detection of far-sightedness and immediate, correctly organized correction is necessary.
Diagnostics of a presbiopiya
At diagnostics of a presbiopiya age characteristics, astenopichesky complaints, and also data of objective diagnostics are considered.
For identification and assessment of a presbiopiya check of visual acuity with the test for refraction, definition of a refraction (a skiaskopiya, computer refractometry) and accommodation volume, a research of finding of the next point of clear vision is made for each eye.
In addition by means of an oftalmoskopiya and biomicroscopy under increase structures of an eye are investigated. For an exception of the accompanying presbiopiya of glaucoma the gonioskopiya and a tonometriya is carried out.
Correction and treatment of a presbiopiya
Correction of a presbiopiya can be carried out by optical, microsurgical and laser methods.
Most often resort to-point correction of a presbiopiya which is carried out by means of collective "plus" lenses. In ophthalmology use specially calculated parameters of force of the glasses necessary for correction of a presbiopiya at each age. So, for an emmetropichesky eye in 40 years lenses +0,75+1 are appointed, further each 5 years increases still on +0,5 (i.e. in 45 years force of glasses will make +1,5 ; in 50 years +2 ; in 55 years +2,5; in 60 years + 3 etc.). As a rule, after 65 years strengthening of correction of a presbiopiya is not required.
At gipermetrop for calculation of optical power of glasses to value of age correction of a presbiopiya it is necessary to add far-sightedness degree. For determination of force of lenses at miop it is necessary to subtract short-sightedness degree from the size of the presbiopichesky lens corresponding to age. It is necessary to consider that these data are approximate and without fail demand specification by a direct pristavleniye of glasses to an eye.
Taking into account need simple glasses for work at a short distance, difficult points (bifocal) with two focuses for sight afar and close, progressive, multifocal lenses or other options of optical correction of a presbiopiya are chosen.
In complex correction of a presbiopiya vitamin therapy, gymnastics for eyes, massage cervical zones, magnetolaser therapy, reflexotherapy, hydrotherapy, an elektrookulostimulyation, trainings on an akkomodotrener is used (device "Streamlet").
Surgical treatment of a presbiopiya can also be variable. In the field of laser surgery the technique of PresbyLASIK by means of which on a cornea the multifocal surface allowing to receive on a retina, both distant, and near focus is formed is successfully applied to correction of a presbiopiya. FRK (photorefractive keratectomy), Femto LASIK, LASEK, EPI-LASIK, Super LASIK, etc. belong to other ways of laser correction of a presbiopiya.
Intraocular correction of a presbiopiya assumes replacement of the crystalline lens which lost the physical and chemical properties and elasticity, ability to accommodation on artificial – an intraocular lens (IOL). For correction of a presbiopiya the special accommodating monofocal IOL or multifocal IOL which are implanted right after a cataract fakoemulsifikation are used.
Prevention of a presbiopiya
Completely it is not possible to exclude development of a presbiopiya – with age the crystalline lens inevitably loses the initial properties. To postpone approach of a presbiopiya and to slow down the progressing deterioration in sight, it is necessary to avoid excessive visual loadings, it is correct to select lighting, to carry out gymnastics for eyes, to accept vitamin medicines (And, B1, B2, B6, B12, C) and minerals (Cr, Cu, Mn, Zn .).
It is important to visit annually the ophthalmologist, to carry out timely correction of anomalies of a refraction, to be engaged in treatment of diseases of eyes and vascular pathology.