Age-related (senile) cataracts

Age-related cataracts (senile) develop in 60-90% of people over 60 years of age. The pathogenesis of cataract development at this age is associated with a decrease in the amount of soluble proteins and an increase in the amount of insoluble proteins, a decrease in the amount of amino acids and active enzymes and the amount of ATP. Cysteine is converted into cystine. All this leads to clouding of the lens. Among senile cataracts, presenile ones are distinguished - coronal cataract occurs in 25% of people who have reached puberty. The opacity of the crescent shape spreads peripherally from the age nucleus, is a strip with rounded edges, which spreads along the periphery of the lens in the form of a crown, sometimes has a blue color

Age-related cataracts are sometimes found not only in older people, but also in people of active mature age. They are often bilateral, but the clouding does not always develop in both eyes at the same time.

Age-related cataracts can be of different localizations. The most common is cortical (90%), less common are nuclear and subcapsular.

In the development of senile cataract, four stages are distinguished: incipient cataract, immature (or swelling), mature and overmature.

Cortical cataracts

Stage I of cataract is the initial stage. The first signs of opacification appear in the lens cortex at the equator. The central part remains transparent for a long time. According to the structure of the lens, opacities look like radial streaks or sector-shaped stripes, the wide base of which is directed toward the equator. When examined in transmitted light, they appear as black backs on a red background of the pupil. The first signs at this stage are "flies" before the eyes, spots, and a desire to rub the eyes.

The crystalline lens is typically hydrated, it is saturated with water, as if it thickens, water cracks appear in the form of radial black stripes. The fibers of the lens are stratified along the periphery - spoke-like opacities. In transmitted light, spokes are visible with such a picture.

Vision with incipient cataracts decreases when opacities reach the pupil area. Myopia may develop. Patients who have developed myopia associated with hydration of the lens stop using plus glasses and note an improvement in vision with less plus correction when reading. At this time, it is necessary to prescribe instillations of vitamin drops. During this period, biomicroscopy is used to recognize the pre-catarrhal state of the lens. Biomicroscopy reveals:

1. symptoms of cortex dissociation. In this case, the cortex is as if dissected, dark layers appear in it - this is water, which is located between the lens fibers of the cortex;
2. a symptom of gaping of the bark seams, or a symptom of the formation of water cracks. In this case, the liquid is located between the dividing zones, and the bark seam gapes;
3. Vacuoles are found under the anterior and posterior capsules, i.e. vacuolization of the lens occurs. When water appears in the lens, it begins to become cloudy. Vision may not suffer. The incipient cataract may remain in a watery state for a long time, but sooner or later it progresses and passes into the second stage of immature (or swelling) cataract.

Stage II cataract - immature cataract. The opacities increase, merge with each other, gradually closing the pupil. Opacities are gray-white in color, the sutures of the nucleus become cloudy. Due to swelling of the clouding fibers, the volume of the lens increases. In this case, the anterior chamber becomes smaller, intraocular pressure may increase compared to the second eye. However, at this stage, not all cortical layers become cloudy, the anterior layers remain transparent. The degree of maturity of the cataract at this stage is determined by the shadow of the iris, which is formed with lateral illumination, when a shadow falls from the pupillary edge of the iris (from the side of the light source) onto the lens. The thicker the layer of transparent anterior layers of the lens, the wider the shadow of the iris, the less mature the cataract. The degree of maturity of the cataract also determines the state of vision. With immature cataract, visual acuity gradually decreases. The more mature the cataract, the lower the object vision. It can decrease to such an extent that a person will not see an object even at a close distance. Swelling of the lens leads to phacomorphic glaucoma.

Stage III cataract is a mature cataract. The lens loses water, becomes dirty gray, and all cortical layers, up to the anterior capsule of the lens, become cloudy. The clouding of the lens becomes uniform, the shadows of the iris are not visible in lateral lighting, the anterior chamber deepens, and the lens decreases in size by the time of maturation, as it loses water. When examined in transmitted light with a dilated pupil, its glow is absent. Object vision is completely lost, only light perception remains. Subcapsular plaques may form against the background of homogeneous clouding under the capsule. Maturation of senile cataract is slow: from one to three years. Those forms in which the clouding begins in the nucleus or in the layers adjacent to it mature especially slowly.

Stage IV cataract - overripe cataract. Overripe cataract can occur in two ways. In some cases, the lens gives off a lot of water, decreases in volume, and shrinks. Cloudy cortical masses become dense; cholesterol and lime are deposited in the lens capsule, forming shiny or white plaques on it.

In other, rarer cases, the cloudy cortical substance and lens masses become liquid, with a milky tint. The breakdown of protein molecules leads to an increase in osmotic pressure, moisture passes under the lens capsule, it increases in volume, the superficial capsule becomes smaller. This phase is called milk cataract. In the overripening stage, dehydration of the lens thus occurs. The first sign of overripening is the appearance of folding of the lens capsule, a gradual decrease in volume. The cortex liquefies during overripening, and the nucleus in it descends downwards. Overripening of a cloudy lens with a lowering of the nucleus is called Morgagni cataract. Through the upper zone of such a lens, a reflex can be seen, and with a plus correction from above, the patient may also have vision.

In such cases, if the patient is not operated, the capsule of the lens begins to let the lens protein through. In this case, phacogenic iridocyclitis or phacotoxic glaucoma may develop, associated with the fact that the lens protein clogs the angle of the anterior chamber of the eye.

Nuclear cataract - it must be differentiated from crystalline lens sclerosis. In cataract, the opacity is distributed to the embryonic nucleus and sutures. In age-related nuclear cataract, central vision is impaired early: distant vision suffers, and "false myopia" develops near vision, which can be up to 12.0 diopters.

First, the embryonic nucleus becomes cloudy, then it spreads to all layers. The cloudy central layers are clearly delimited from the peripheral transparent zone. There is no disintegration of the lens substance. This is a dense cataract. Sometimes the nucleus can acquire a brown or black color. This cataract is also called brown. Nuclear cataract remains immature for a long time. If it matures, then it is called a mixed cataract - nuclear-cortical.

Subcapsular cataract is an age-related, very insidious disease, since the youngest peripheral part of the lens becomes cloudy, primarily the anterior capsule, under it vacuoles and opacities develop - delicate, of varying sizes. As the opacities increase, they spread to the equator and resemble a cup-shaped cataract. The opacities do not spread to the cortex of the lens. Cataracts must be differentiated from complicated cataracts.

The origin of senile cataracts is currently associated with disturbances in oxidative processes in the lens, caused by a deficiency of ascorbic acid in the body. Of great importance in the development of senile cataracts is also a deficiency of vitamin B2 (riboflavin) in the body _. In this regard, in the case of incipient senile cataracts, in order to prevent the progression of cataracts, ascorbic acid and riboflavin are prescribed in the form of eye drops or riboflavin with potassium iodide (also in the form of eye drops).

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ], [ 10 ], [ 11 ], [ 12 ]