Cataract

Synonyms in a broader sense

clouding of the lens, cataract, age cataract

Definition

Cataract (this term, like the “glaucoma“, should not be used any more, because of the danger of confusion with the “other” star). Cataract generally refers to any form of lens opacity. In humans, the normally transparent lens is located behind the pupil and is part of the optical apparatus with which the eye can adjust its focus.

In advanced cataracts, a grey veil can be seen behind the pupil. This is where the term “cataract” comes from: “grey” because of the veil and “star” because of the fixed gaze that can be observed in blind people. The word cataract originally comes from the Greek (cataracta) and means “waterfall”. At that time it was assumed that the gray veil was a coagulated liquid that had flowed down in front of the pupil. The resulting cloudiness of the field of vision gave the impression of looking through a waterfall.

How often does cataract occur?

In the over 65-year-olds almost 100% have a cataract and about 50% notice the visual disturbances when they reach the age of 75. Every year between 400,000 and 600,000 people in Germany are operated for cataracts. Overall, untreated cataracts are the most common cause of blindness in the world.

The most common form is age-related cataract = cataract. Within the scope of cataracts the lens in the eye becomes cloudy. This clouding is also called cataract.

A cataract is said to occur as soon as the clouding of the lens greatly impairs daily life. This clouding makes the lens opaque to light and causes a slow decrease in vision, which can lead to complete blindness and deterioration in visual acuity. Cataracts are the most common cause of blindness in the world.

The main symptom of cataracts is the ever decreasing visual acuity. Due to crystals that originate from altered structural proteins in the lens of the eye, light no longer reaches the retina unhindered and the lens loses its transparency. The gray haze is a typical sign of a beginning cataract.

Contrast and colors are increasingly difficult to see, as if through fog. The comparison, as if looking through a fogged window pane, expresses how limited the affected persons are, especially in the later course of the cataract. At this point, the gray coloration of the pupil is usually visible to others and in photographs the affected persons no longer have so-called “red eyes“.

In addition, the incident light is additionally scattered by the clouding and thus leads to an increased sensitivity to glare in backlighting, which can be a further sign. This is particularly noticeable and very unpleasant when driving in the dark. Also contrasts or colors are only perceived in a weakened way.

Often, in addition to a decrease in vision with cataracts, double vision also occurs. An existing presbyopia improves apparently without reason, which is also a sign of cataract. In the short term, near vision can improve, so that for a certain period of time glasses are no longer needed in 90 percent of all cataract diseases are cataracts of old age (cataract senilis).

If left untreated, cataracts lead to blindness. In many elderly people, however, the ability to see through cataracts diminishes so gradually that surgery is not necessary. 90 percent of all cataracts are cataracts of the elderly (cataract senilis).

If left untreated, cataracts lead to blindness. In many elderly people, however, cataracts cause their vision to deteriorate so gradually that surgery is not necessary. Cataracts are diagnosed by the ophthalmologist on the basis of the symptoms described above and by examining the lens at the slit lamp (device used to illuminate the eye) and visual acuity.

If the opacity is so pronounced that it is not possible to examine the background of the eye, an ultrasound examination can also be useful for cataracts. It is quick, painless and can provide information about: the tissue exposed to ultrasound, in this case the posterior segment of the eye.

• Thickness
• Consistency and
• Changes

Comparison of a pair of eyes.On the left, the milky coloration of the pupil was conspicuous by the cataract, while a healthy eye is shown on the right.

The cataract forms (forms of cataracts) are first divided into acquired and congenital types. Acquired cataract forms make up about 99% of all cataracts (cataracts). The congenital cataracts can also be classified according to their origin in the birth canal (congenital) and their genetic origin (congenital) and therefore also in the case of otherwise uninfluenced development: This is different in the case of congenital cataracts, because the child’s vision has yet to develop.

This is a very complicated process and can only happen in the first years of life. If the development is disturbed during this time, lifelong visual disorders up to blindness result.

• The age cataract (over 90% of all acquired cataracts) = this disease is usually called “cataract
• Cataracts caused by general diseases such as: diabetes mellitus galactose intolerance kidney diseases kidney failure tetanus various other muscle and skin diseases
• Diabetes mellitus
• Galactose intolerance
• Diseases of kidney and kidney failure
• Tetanus (lockjaw)
• Various other muscle and skin diseases
• Cataracts due to inflammation of the eyes
• Postoperative cataracts after vitrectomy
• Injury (traumatic) cataracts caused by accidents Foreign bodies penetrated after accidents Electric shocks Radiation exposure
• Accidents
• Penetration of foreign bodies
• Electroshock
• Radiation exposure
• Toxic (pharmacologically or toxically produced) cataracts
• Cortisone – containing medicines
• Certain eye drops used in glaucoma therapy (glaucoma = glaucoma and parasympathomimetics)
• Diabetes mellitus
• Galactose intolerance
• Diseases of kidney and kidney failure
• Tetanus (lockjaw)
• Various other muscle and skin diseases
• Accidents
• Penetration of foreign bodies
• Electroshock
• Radiation exposure
• In the birth canal acquired by viral infections rubella mumps (rather rare)
• Rubella
• Mumps (rather rare)
• Genetically either X- chromosomally inherited trisomy 13 and 15 Down syndrome and other syndromes
• Either X- chromosomally inherited
• Trisomy 13 and 15
• Down syndrome and other syndromes
• Metabolically related to galactosemia (an intolerance to a certain sugar component)
• Rubella
• Mumps (rather rare)
• Either X- chromosomally inherited
• Trisomy 13 and 15
• Down syndrome and other syndromes

Since the artificial lens no longer allows for near or far adjustment of the sharpness (accommodation), the patient still needs glasses.

Either for the distance or reading glasses for the near. After cataract surgery, the patient should rest for the next 4 – 6 weeks. This means no unnecessary heavy physical work, no competitive sports, if possible no swimming, avoid sauna and also no pressure on the eye.

Before artificial lenses were available, cataract glasses were prescribed. Today, these are rarely necessary if either no artificial lens could be inserted or if there is an intolerance to contact lenses. Cataract spectacles are very strong plus – glasses with approx.

12 – 15 diopters. This means that all objects are perceived about 25 percent larger. But here too, care must be taken that the difference in refractive power between the right and left eye is not too great, otherwise an image will be perceived differently in both eyes.

For this reason, cataract glasses often had only one lens with the particularly strong refractive power. In the case of a one-sided lentlessness, contact lenses are therefore better, because the closer the distance to the eye, the smaller the difference in image size. If the clouding of the lens caused by cataracts worsens significantly and severely restricts normal vision, surgery is the only treatment option.

This operation has become a routine procedure in Germany and is almost always successful.

• Procedure: Cataract surgery can be performed as an outpatient or inpatient procedure.An inpatient stay after such an operation lasts about 2-3 days. Both eyes are never operated on at the same time.

  Initially, only one eye is operated on, and after it heals, the other eye is operated on. The operation is usually performed under local anesthesia. For this purpose, an anesthetic is either dripped in drop form directly into the eye to be operated on or it is injected into the vicinity of the eye with a syringe.

  During the subsequent operation, the clouded lens of the eye is removed and replaced by a new lens made of plastic (so-called intraocular lens). The most commonly used procedure is the so-called phacoemulsification. In this procedure, a small incision is made in the envelope of the eye lens (lens capsule).

  Using ultrasound, the lens core can then be liquefied and sucked out together with the lens cortex through the incision in the capsule. The new, artificial lens is then inserted into the capsular bag. This is usually painless for the patient.

  Finally, the eye is covered with an ointment bandage, which should be left in place for a few days, especially at night, for protection.

• After the operation: Some things are urgent after the eye surgery. Under no circumstances should the operated eye be rubbed. It should also not come into contact with water in the first few days.

  Special care should be taken when washing the hair. Physical exertion should only be resumed after consultation with the doctor. This also applies to participation in road traffic, which should only be practiced after a satisfactory eye test has been performed.

  Since the strength of vision can vary greatly in the first few weeks after the operation, it is necessary to wait before fitting new glasses. Most patients also need sunglasses after the operation, as the new lens is more transparent than the old clouded lens.

• Timing: The time when cataract surgery should be performed depends on the individual patient. On the one hand, it depends on the extent to which the patient’s vision is already impaired and whether it already interferes with the patient’s everyday life.

  On the other hand, age plays a major role. Younger patients, who for example are still actively involved in traffic, should be operated on with less loss of vision than older people, who are mainly at home. In the case of congenital cataracts, the child should be operated on as soon as possible, as this is the only way to learn to see without complications.

• Lens types: The inserted new lens can be individually adapted to the patient.

  Various materials are available (e.g. polymethyl methacrylate=Plexiglas, silicone, acrylic). In addition, the new lens can create one or more focal points and be adjusted for near or far vision. Nowadays “soft”, foldable lenses are mostly used.

  These can be transplanted into the eye in rolled form and therefore require a smaller incision than the “hard” lenses. This reduces the occurrence of complications. Finally, special lenses are also available, but these are not suitable for all patients.

  They may contain special color filters and may also allow progressive vision.

• Complications: In the majority of patients the operation is very successful (90% of patients have better vision). However, concomitant diseases of the patient can significantly influence the success of the operation. For example, patients with other eye diseases, such as retinal diseases, circulatory disorders of the optic nerve or age-related macular degeneration (AMD) will see less improvement in vision.

  Another risk of the surgery is that the capsular bag will be damaged when the clouded lens is removed and it will not be possible to insert a new lens afterwards. In such a case, however, alternative procedures are usually available, in which the new lens is inserted directly behind the pupil, for example. Other complications include swelling or detachment of the retina, a protrusion of the vitreous body when the lens capsule is damaged or infections in the surgical field.

  However, these can usually be easily treated with modern drugs.

• Post-star: In some cases, there is a gradual loss of the initially improved visual performance after several weeks or months after surgery. This so-called after-star can, however, be easily corrected in an additional small operation with a laser.

In the meantime there is the possibility to treat cataracts with laser besides the surgical operation method. With this new technique, a special laser (femtosecond laser) takes over the incisions in the eye that were previously made manually by the surgeon.

The laser emits light pulses in the range of femtoseconds (1/14 of a second), releasing high energy that can be used for the surgical incision. The incisions are planned beforehand by the surgeon and constantly monitored during the operation using a microscope. Laser treatment is intended to provide more precise and safer cataract therapy and better quality of vision through more precise alignment of the artificial lens.

Irritation symptoms that may occur in the eye after the surgical treatment are also less frequent: the laser requires only a fraction of the ultrasound energy to shatter and suck out the old lens, as in the conventional procedure. A further advantage is that the laser can also correct a simultaneous corneal curvature of the eye, as this can be corrected by the laser during the operation. The procedure can be performed under local anesthesia with eye drops and on an outpatient basis.

However, due to the high acquisition costs, treatment with the femtosecond laser is not yet possible in all clinics. The causes of cataract are very diverse. The most common is age-related cataract (Cataracta senile = cataract), which cannot be attributed to any specific cause.

Most likely, this form of cataract can be attributed to the poorer supply of nutrients to the lens in old age. Other acquired cataracts can be better attributed to the cause. For example, injuries to the eye (cataracta traumatica) and radiation exposure (especially X-rays, infrared rays and UV light) can be the cause.

Chronic inflammation of the choroid (cataracta complicata), as is the case with bacterial or viral infections, can also cause cataracts. Malnutrition (especially vitamin A deficiency, often a problem in developing countries) and many diseases that influence the lens metabolism (such as diabetes mellitus) are possible causes of cataracts. In principle, therefore, everything that can disrupt the nutrition and supply of oxygen to the lens.

However, a cataract does not always have to be acquired, but can also be congenital (cataracta congenita) or develop during pregnancy (cataracta connatale) as a result of intrauterine, i.e. prenatal, infection of the mother (e.g. by the measles and rubella virus). In such cases, cataract surgery must be performed as soon as possible, otherwise there is a risk of weakness of vision (amblyopia).

• Optic nerve (nervus opticus)
• Cornea
• Lens
• Anterior eye chamber
• Ciliary muscle
• Glass body
• Retina (retina)

The prospects for better vision after cataract surgery are in principle very good. The prerequisite is, of course, that no other eye disease disturbs vision and that any existing underlying disease is treated appropriately. In the treatment of cataract in children, the most important thing is that the therapy is started in time.

Side note: Sometimes so-called “anti-cataracts” are prescribed. These are drugs that are supposed to be effective against lens clouding. Rare complications in cataract treatment are the rupture of the posterior capsule and bacterial infection.

In most cases, the bacteria are not transmitted by unclean instruments, but come from the patient’s own conjunctival sac. Patients with a weak immune system (e.g. AIDS) or general diseases such as diabetes mellitus or neurodermatitis are particularly at risk. A particular late consequence of cataract surgery can be the after-star.

The term post-star is used to describe a clouding of the posterior capsule. The clouding is either caused by a change in the tissue or by a regeneration of cells on the lens surface (lens epithelial cells), which were not completely removed during the operation. One can then try to cut the central part of the posterior capsule with a laser or remove the regenerated cells with a suction cup.

In addition to wearing special cataract glasses or contact lenses, the removal of the patient’s own lens and the simultaneous replacement with an artificial lens can also be considered as a therapy.As soon as a drastic restriction of everyday life due to cataracts occurs, surgical removal of the lens should be considered. The lens of the eye consists of three parts: the capsule, the cortex and the nucleus. When the lens is removed, the capsule is preserved and the new artificial lens is inserted into it.

The surgical procedure is performed as an outpatient procedure under local anesthesia. Before the operation, the exact strength of the new artificial lens is calculated individually for each patient, based on the total refractive power of the affected eye. The intraocular lens (IOL) is the most commonly used implant in medicine worldwide.

It is an artificial lens, which is available in different material and lens types, so that a suitable lens can be found for each patient. The lenses can be made of PMMA (Plexiglas), silicone or acrylic. The latter two materials are foldable and therefore require a smaller incision during insertion.

However, they can only be used to make posterior chamber lenses, while PMMA can be used for anterior and posterior chamber lenses. It is also possible to divide them according to the implantation site: there are lenses that are inserted behind the iris (posterior chamber lenses) and lenses that can be placed in front of the iris (anterior chamber lenses). The method of choice are posterior chamber lenses, as they have fewer complications and the location has proven to be the best.

A further classification is based on the number of existing focal points: Monofocal lenses are the standard model of intraocular lenses. They produce only one focal point and allow sharp vision at distance or near. However, with this model, glasses for near or far vision must always be worn after the operation, as the artificial lens cannot change its curvature and thus the adaptation of near and far vision (accommodation) is not possible.

Multifocal lenses, on the other hand, have several focal lengths and are intended to enable sharp vision at near and far distances. Therefore, glasses do not need to be worn for most everyday activities, but they can be used in the dark or for observation at night. The decision which type of lens to use must therefore be made individually for each patient according to his or her needs.

Months to years after the operation a regenerative after-star can occur, which manifests itself in a renewed deterioration of vision. Then a further surgical intervention may be necessary. The decision which type of lens is inserted must therefore be made individually for each patient according to his or her needs.

Months to years after the operation a regenerative after-star can occur, which manifests itself in a renewed deterioration of vision. Then a further surgical intervention may be necessary. Already in the ancient Egyptians cataracts were treated by the so-called cataract engravers.

In this procedure, an incision was made in the side of the eye, the so-called cataract needle was advanced up to the lens and the lens was pressed down to the base of the eyeball. This freed up the view, even though focusing was no longer possible. However, infections often occurred, which often led to blindness.

In this country, such operations were performed in the Middle Ages. Mostly by traveling wound healers, who offered their services at festivals and fairs. They could therefore often not be prosecuted when blindness occurred weeks later.

The composer Johann Sebastian Bach was thus treated on both eyes. He never recovered, went blind and died of the consequences.