Synonym
Clouding of the lens, cataract = cataract (med.)
Definition – What is lens opacity?
Clouding of the lens occurs when the lens, an important component of the eye for vision, is no longer transparent but cloudy. This clouding is often grayish, which is why the clouding of the lens is often referred to as “cataract” in the vernacular even today. In medicine, the clouding of the lens is called “cataract“.
Clouding of the lens usually occurs with aging, but can also be caused by medication or an accident, for example. If the clouding of the lens results in a significant reduction in vision, surgical therapy is applied, which usually improves the quality of life of the affected person significantly. Clouding of the lens usually leads to quite characteristic symptoms.
In the most common form of lens clouding, i.e. senile lens clouding in the course of aging, the symptoms occur gradually over several years and become more and more pronounced. One of the symptoms of clouding of the lens is a deterioration in vision, since the lens is no longer transparent and the light from outside is therefore less effective. There is an increasing sensation of glare, so the light is perceived as brighter and more unpleasant.
In addition, the vision of colors can change and in advanced stages, the vision can become increasingly gray. In some cases, double images also occur as the lens clouding progresses. In the rarer form of congenital opacity, on the other hand, the red light reflex in a photograph may be absent and the lens may become strabismus.
The diagnosis of lens clouding is usually made by an ophthalmologist. For this purpose, an examination with the so-called slit lamp is usually performed. This is a light apparatus frequently used by ophthalmologists to examine the eye.
This examination can detect clouding of the lens, usually grayish-brownish, or even yellowish. In the case of advanced lens opacity, clouding of the lens can already be detected without the use of examination equipment. In addition, vision tests can be used to determine whether the clouding of the lens is causing a reduction in vision.
As a rule, clouding of the lens is treated surgically. Healing of the clouding of the lens cannot be achieved with medication. There are various surgical options for the treatment of clouding of the lens.
First of all, it must always be questioned whether the operation is appropriate. This is the case if there is a significant deterioration in vision with restrictions in everyday life. The most common method used today is the so-called extracapsular cataract extraction.
Here, the anterior section of the lens, the so-called anterior capsule, is opened through a very small incision. Then the core of the lens (the area of the lens that usually contains the most opacity) is liquefied by a powerful ultrasound device. This liquefaction of the lens core by ultrasound, which was specially developed for cataract surgery, is also known as phacoemulsification.
The core is then removed and a posterior chamber lens is inserted to stabilize the posterior section of the lens, the so-called posterior capsule. This operation is one of the most common operations in the world today and usually has a very good prognosis. In about 30% of cases, however, there may be a post-star, i.e. a recurrence of the lens opacity.
The causes of lens clouding can be very diverse. First, a distinction can be made between congenital lens clouding, so-called congenital forms, and acquired forms. The congenital form accounts for less than 1% of all lens opacities and can either be inherited or caused by an infection during pregnancy or birth.
The much more common form is acquired lens opacity. Of these, over 90% are senile lens clouding. This is a clouding of the lens as a result of natural aging.
The exact mechanisms are not fully understood, and it is believed that the lens is not nourished with sufficient nutrients. Frequently, other basic diseases such as diabetes mellitus or renal insufficiency also play a role. However, in rare cases these can also cause clouding of the lens without the aging process.
Other causes of acquired lens clouding can be medication, such as cortisone. An accident with a bruise of the eye can also lead to clouding of the lens. Very rarely, clouding of the lens can also occur during an eye operation or as a result of radiation, such as X-rays or infrared radiation.The prognosis of lens opacity depends on whether surgery is necessary and if so, how it is performed.
In most cases, surgery can result in a significant improvement in vision and thus a regained quality of life. Without surgery, in advanced stages of the disease, complete loss of vision can occur. Furthermore, glaucoma, also formerly known as “glaucoma”, is a possible consequence if there is no therapy.
A possible complication of a lens opacity operation is a recurring clouding of the lens as a result. This occurs in about 30% of patients who have undergone so-called extracapsular cataract extraction. This is the most common surgical method used to treat clouding of the lens.
Among other things, a posterior chamber lens is used to stabilize the posterior part of the lens, the so-called posterior capsule. After the operation, a proliferation of cells of the lens surface, the so-called lens epithelium, can cause renewed clouding of the lens. The cells migrate into the operated lens and thus lead to a renewed clouding of the lens.
This is also known as “after-star”. There is a special surgical procedure to correct this new clouding of the lens. A so-called YAG laser, a special laser for the lens, is used.
This time the posterior capsule of the lens is opened and the laser is used to destroy the excessively accumulated cells. Clouding of the lens can occur as a side effect of various drugs. These include, for example, glucocorticoids with cortisone as the most common representative.
But also so-called Miotika, i.e. drugs that cause a temporary reduction in the pupil – in the course of diagnostic and therapeutic examinations – can lead to lens opacity if used over a long period of time. In rare cases, cataracts can also occur as a result of poisoning, for example, poisoning with ammonia. Clouding of the lens due to cortisone In a few cases, drugs such as cortisone can also cause clouding of the lens.
The exact mechanisms are not yet understood. Both local and systemic cortisone treatment can cause clouding of the lens. A local treatment would be, for example, an injection with a syringe or the application of an ointment in the context of an infection of the eye.
Systemic treatment, on the other hand, means the administration of cortisone into the vein or the taking of cortisone tablets, for example in the case of lung disease. In rare cases, clouding of the lens may occur in babies. This type of lens opacity is also called congenital form, which means “congenital”.
Clouding of the lens in babies can either be inherited or caused by an infection during pregnancy or birth. The most common infections include rubella, mumps and hepatitis. In rare cases, a so-called galactosemia, a metabolic disorder in the breakdown of sugar, can also be the cause.
One of the symptoms of lens clouding in babies is leukocoria, i.e. the absence of the red light reflex of the retina, which is clearly visible when taking photographs, for example. In addition, strabismus and a delay in the child’s development occurs because the child’s vision is impaired. Depending on the degree of lens opacity in the baby, surgical therapy is also used here. If the lens is cloudy due to galactosemia, this can be completely reduced by a galactose-free diet.