Scientists have long established a direct connection between the presence of diabetes mellitus in a person and the occurrence of certain eye diseases. After all, the negative impact of high blood sugar levels extends to the vascular system of the entire body, including the organ of vision. At the same time, damaged vessels will quickly collapse, and newly formed ones are characterized by increased fragility of the vascular walls. This leads to the accumulation of excess fluid in the tissues, including exudate in the eye area, as a result of which visual functions deteriorate and clouding of the lens substance occurs.
Material for patients “Diabetes School”
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1st and 2nd parts of the lecture
May 20, 2001
Mazurina Natalya Konstantinovna
head dept. Laser Surgery Center for Diagnostics and Surgery of the Posterior Eye
Eye (ocular
apple) is a ball with three shells and contents.
Rice. 1. The structure of the eyeball.
The first shell - the outermost - is called connective tissue and consists of the sclera
(thick white tissue) and the cornea (a transparent, spherical, smooth, shiny structure that resembles a lens).
The sclera
primarily performs supporting and protective functions.
The cornea is the main structure that refracts rays entering the eye
(the refractive power of the cornea is approximately 40 D).
The innermost layer of the eye
The apple is made up of the choroid.
The name itself - vascular - means that the bulk of this tissue consists of vessels of different diameters. And, of course, the main function of this eye shell is to maintain nutrition of the entire eyeball
.
This membrane of the eye
has a complex structure and consists of three parts - the iris, the ciliary body and the choroid itself.
The iris is the part of the choroid visible in the eye
slits through the transparent cornea.
The amount of colored pigment in the iris determines eye
.
Another important formation of the iris, the pupil is an opening whose size regulates the amount of light entering the
retina
inside the eye .
Ciliary body
- the more internal part of the choroid.
Its main task is the production, production of intraocular
fluid, through which other parts
of the eye
(cornea,
lens
,
vitreous body
...) are nourished.
Another important function of the ciliary body
is participation in the act of accommodation - adapting
the eye
to perceive objects located at different distances.
The third part of the choroid is called the choroid proper, and it makes up the majority of it. Its main function is to maintain nutrition of the retina
- the most energy-intensive tissue of the body.
And finally, the innermost layer of the eyeball, which is responsible for the perception of visual information, is the retina
or simply
retina
, Latin name -
retina
.
In terms of its structure, it is a highly organized nervous tissue; in fact, it is a part of the brain removed from the cranial cavity into the orbit. The retina
is the tissue that perceives light information, processes it into a nerve impulse and sends it to the brain along
the optic nerve.
The optic nerve consists of long processes of
retinal
.
In the visual
a visual
is formed based on the information received .
Structure of the retina
very complex, in terms of energy level - it is one of the most energy-intensive and energy-dependent tissues of the body, especially its central region.
The retina
nourished from two sources: from its own vessels and from a powerful network of vessels in the underlying choroid.
What does the retina
?
What does the doctor see when examining the fundus
(Fig. 2)?
Rice. 2. Fundus
fine.
Anatomically the retina
divided into central and peripheral parts.
In the central region there are the optic nerve
, vascular bundles - arcades and the so-called
macula
.
Yellow spot
- this is the most important part of the retina, the Latin name is
macula (macula)
.
The “work” of this particular zone ensures high visual acuity
, the ability
of the eye to see
small objects, read, and perceive colors.
As you move away from it, the ability of the retina
decreases: already in the area of vascular bundles (arcades),
the retina
can give
visual acuity
of less than 0.1-0.2, i.e.
the ability to read is lost. The peripheral areas of the retina
provide a wide
field of vision
, the ability
to see
large objects, especially in poor lighting (twilight, night);
the extreme periphery of the retina
is only capable of distinguishing light, i.e. practically functionally inactive.
Retinal damage
As you know, the retina of our eye is responsible for the perception of light and the transmission of nerve impulses to the brain, and therefore is the most important structure providing visual perception of the surrounding world.
The retina tissue consumes more glucose and oxygen per unit of its weight than any other tissue in our body, so it requires a good blood supply. However, with diabetes, pathological changes occur in the blood vessels that supply the retina, which leads to the development of a specific lesion of the retina - diabetic retinopathy (more about this disease: https://www.okomed.ru/diabet.html). This disease develops gradually and is poorly diagnosed in the early stages. In addition, it is difficult to treat and can result in blindness. The need for retinal surgery in diabetes is often due to the development of diabetic retinopathy.
Lens
This is a transparent formation that resembles a lens. It consists of anterior and posterior capsules and contents - a specially “laid” transparent protein.. Vessels in the lens
no, it is powered by substances brought in by
the intraocular
fluid.
Lens
is located behind the iris and is visible immediately behind the pupil.
The function of the lens
is refractive (the refractive power
of the lens
is about 20 D).
This is a kind of optical lens that, together with the cornea, focuses rays onto the retina
.
But unlike the cornea, the lens is
a more “mobile” system, because by changing its curvature, it is able to refract in different ways, adapting the eye to perceive objects at different distances.
Normal lens
- a perfectly transparent formation.
Transparency is ensured by the special structure of specific proteins. When exposed to unfavorable factors (metabolic disorders, radiation, trauma), the unique structure and arrangement of lens
and its transparency is impaired.
Thus, the lens
“sick” with only one disease - loss of transparency, in other words -
the lens becomes cloudy
.
Cataract
any nature, any localization and intensity is called “
cataract
”.
Therefore, the diagnosis of cataracts
should not frighten patients.
This diagnosis does not mean that a person is at risk of blindness
and urgent
surgical treatment
.
The diagnosis of “ cataract
” is made if there is at least minimal opacification in any part
of the lens
(Fig. 3).
Rice. 3. Cataract. Cloudiness
in the cortical layers and along the posterior capsule.
Intensity and localization of opacities in the lens
may be stable over a long period of time and do not require
surgical treatment
.
Diagnostics
Methods for diagnosing diabetic retinopathy are not particularly specific and include standard ophthalmological examination procedures:
- analysis of complaints and anamnestic information;
- accurate measurement of visual acuity (visometry);
- biomicroscopic examination of the anterior segment of the eye;
- biomicroscopic examination of the retina using aspherical lenses;
- direct and reverse ophthalmoscopy;
- stereoscopic photography;
- fluorescein angiography of the retina (one of the types of contrast radiography);
- ultrasound examination of the eye;
- optical coherence tomography;
- duplex scanning of blood vessels.
Typically, the examination is comprehensive and includes several diagnostic methods. The objectives of such an examination are to assess the general condition of the multilayered retinal tissue and the circulatory system that feeds it, early detection of areas of ischemia (insufficient blood supply) and incipient neovascularization, identification of microhemorrhages, areas of swelling, mechanical ruptures, etc. It is also important to evaluate the effectiveness of preventive measures and the general dynamics of the retina during treatment.
Vitreous body
Vitreous body
fills
the eye
by almost 4/5 of its volume.
It is a gel-like mass reminiscent of chicken protein. Like the lens, the vitreous body
does not have its own vessels and is nourished by the blood supply to neighboring tissues and
intraocular
fluid.
Like the lens, the vitreous body
is surrounded by a kind of capsule, which is more often called the
vitreous
.
Vitreous body
- the least studied part
of the eye
, despite the fact that it is a very important structure.
It borders on such important formations as the lens, ciliary body
, and most importantly,
the retina
.
It is the relationship between the retina and the vitreous body
(more precisely, the membrane surrounding it) that determines the severity of the manifestations
of diabetes mellitus in the eye
; most often,
intraocular
hemorrhages occur directly into
the vitreous body
.
For a long time it was believed that the eye
cannot exist without
the vitreous body
, which supposedly is a necessary support
for the retina
.
It has now been reliably proven that the eye
can function absolutely normally without this structure.
The operation to remove the vitreous
is called
vitrectomy (vitreectomy)
.
The cavity occupied by the vitreous body
, after the operation, is eventually filled with its own
intraocular
fluid, and
the eye
is able to function and provide good
vision
in new conditions of existence.
But these operations
will be discussed a little later.
For diabetes mellitus (DM)
of the eye
are affected to one degree or another .
Therefore, the ocular
manifestations
of diabetes mellitus
are very diverse.
Drug therapy for glaucoma
This approach has three main directions:
- Specific therapy that improves blood supply and nutrition to the optic nerve and other structures of the eye.
- Antihypertensive treatment that normalizes the level of intraocular pressure.
- Drugs that stimulate metabolic processes in the body and also slow down reactions leading to degeneration of eye structures.
When carrying out complex treatment, it is almost always possible to do without surgical intervention.
Changes in the refractive power of the eye
Various metabolic disorders in diabetes lead to changes in the refractive ability of some eye
.
Quite often, in patients with type 1 diabetes, when the disease is initially diagnosed against the background of high blood sugar levels, the effect of a “ myopic eye”
"
At the beginning of insulin therapy, with a sharp decrease in glycemic levels, some patients' eyes
become farsighted.
The literature describes cases of farsightedness up to +6.5 D. The effects of both "myopic" and "far-sighted" eyes
are perceived by patients as a significant decrease
in vision
.
Children sometimes lose the ability to read and distinguish small objects at close range. Over time, when blood sugar levels normalize, these phenomena disappear, vision
returns to normal, so we usually do not recommend choosing glasses when
diabetes is
during the first 2-3 months.
Patients with type II diabetes usually do not experience such dramatic changes in the refractive power of the eye.
.
This type of diabetes is more characterized by a gradual decrease in the adaptive ability of the eye
, especially when working at close range.
Therefore, these patients begin to use reading glasses earlier than their peers. Episodes of sudden, significant vision
in people suffering from type II diabetes are often caused by other, deeper problems and require a careful examination
by an ophthalmologist
and accurate diagnosis.
What to do to delay vision deterioration.
Now many doctors believe that diabetes mellitus is not just a disease that can be compensated for with medications, diabetes mellitus is an absolute lifestyle change. Only timely consultation of the patient with a doctor and strict adherence to recommendations can prevent the development of serious complications of diabetes. Patients need to change their eating behavior, lose excess weight, lose smoking, exercise regularly, monitor blood glucose levels, compensate for arterial hypertension, and take prescribed medications.
Studies have shown that maintaining blood pressure within normal limits reduces the risk of cardiovascular complications by approximately 33%.
Paralysis and paresis of the oculomotor nerves
Quite often, in patients with diabetes, nervous tissue suffers, which leads to disruption of innervation (nervous regulation) of muscle tone and function, including oculomotor muscles
.
These disorders are expressed in the appearance of drooping of the upper eyelid, the development of strabismus
, double vision, and a decrease in the amplitude of movement
of the eyeballs
.
Sometimes the development of such symptoms is accompanied by eye
and headaches.
More often, such changes occur in patients with type II diabetes and are sometimes the first manifestation of the disease.
This complication occurs infrequently and, according to the literature, does not depend on the severity of diabetes
(more often occurs with moderate diabetes).
If such manifestations develop, it is necessary to consult not only an endocrinologist
, but also a neurologist. Treatment is often prescribed by a neurologist, taking into account the causes of the development of these disorders. Treatment can be long-term (up to 6 months), but the prognosis is favorable - restoration of function is observed in almost all patients.
Cataract
As mentioned earlier, cataracts
- this is
clouding of the lens
in any layers and any intensity.
In diabetes mellitus
(especially type I), a specific form
of cataract
- the so-called
diabetic cataract
- flake-like
opacification
along the posterior capsule
of the lens
.
For type II DM, the age-related type of cataract
, when
the lens becomes cloudy
diffusely, almost evenly in all layers, sometimes
the opacities
have a yellowish or brown tint.
Quite often cloudiness
They are very gentle, translucent, and do not reduce
vision
or reduce it slightly.
And this state can remain stable for many years. In case of intense opacities
, with rapid progression of the process, it is possible to perform
an operation to remove the cloudy lens
, but the decision to perform
the operation
, as a rule, is the choice of the patient.
Modern surgery
stepped far forward.
About 15 years ago, diabetes mellitus
was a contraindication to
cataract surgery
followed by
implantation of an artificial lens
.
Previously existing technologies suggested waiting for the complete “maturation” of the cataract
, when
vision
dropped almost to light perception.
Modern techniques ( transciliary lensectomy, ultrasonic phacoemulsification
) make it possible to remove
cataracts
at any degree of maturity, through minimal incisions,
and to implant
high-quality
artificial lenses
.
In the early stages of cataracts
, when
visual acuity
is not reduced and
surgery
is not yet indicated, we suggest patients instill vitamin drops.
The goal of the treatment
is to maintain the nutrition
of the lens
and prevent further
clouding
, i.e., in fact, the goal is preventive.
Vitamin drops are not able to resolve existing opacities
, since the resulting changes in
the lens
are associated with irreversible changes in proteins that have lost their unique structure and transparency. Vitamin drops are a collection of vitamins, amino acids and nutrients; they are an additional source of nutrition for the structures of the eye.
Vitamin drops include “Taufon”, “Katalin”, “Senkatalin”, “Oftan-Katachrome”, “Vitafacol”, “Quinax”.
What tests need to be taken to detect retinopathy?
Modern ophthalmology has stepped far forward; thanks to high-tech, non-contact instrumental research methods, the diagnosis is made in a few minutes and is beyond doubt. Then, taking into account the clinical picture of the disease, an individual treatment plan is prescribed for each patient. For diabetic retinopathy, laser treatment of the retina, injection of drugs into the cavity of the eyeball, surgical interventions for complicated diabetic cataracts, traction retinal detachment, prescription of drops to reduce intraocular pressure, as well as drugs for resorption of hemorrhages, etc. are used.
Unfortunately, approximately half of patients with diabetes come to the doctor too late.
People with type 1 and type 2 diabetes should have an eye examination at least once a year.
