Cataract surgery

Introduction

Currently, the only successful treatment for cataracts is surgery. It is important to determine the underlying cause. As with all treatable diseases, an operation can only bring long-term improvement if the underlying disease is treated appropriately.

Today, cataract surgery is a common method and probably the most frequently performed operation worldwide. Through many years of experience, serious complications have been reduced to a minimal (approx. 1%) residual risk.

Usually a cataract operation is performed within 20 minutes. In the course of time, various methods of treatment have been developed. First of all, one can distinguish between so-called intracapsular and extracapsular operations.

  • In intracapsular methods, the entire lens with its capsule (coating) is removed. This procedure was often used in the past. Nowadays, however, it is only performed in rare cases when the lens capsule can no longer be preserved.
  • With the extracapsular methods, only the anterior lens capsule is removed.

    Then the contents of the lens are crushed and aspirated using ultrasound. The posterior capsule is left in place. In this way, the anterior and posterior segments of the eye (behind the lens) remain naturally separated and the complications are less than with the intracapsular methods.

After removal of the lens, the human eye is initially unable to see objects at close range sharply, as it lacks the refractive power of the lens.

This kind of lentlessness is called aphakia. With the help of insertable artificial lenses it has become possible to treat this problem. Artificial lenses have been developed that can be inserted into the eye.

The refractive power is calculated in advance with an ultrasound device and compared with the other eye. This is because the refractive power – differences between the two eyes must not be too great, because otherwise different image sizes are formed on the retina and the brain can no longer put the two images together (fuse). Three types of lenses can be distinguished: Artificial lenses are either made of PMMA (polymethyl methacrylate or also called Plexiglas), silicone rubber or acrylic copolymers (used mainly for foldable lenses).

The material properties have been developed in such a way that even over decades no toxic products are released or the lenses dissolve in aqueous humor. In children, cataract treatment is somewhat more difficult, because the eyes are still growing and the size and refractive power are still changing. Therefore, children under the age of 2 years are first corrected with contact lenses.

After the 2nd year of life, artificial lenses are usually inserted. But here too, special calculations are made for the refractive power and growth.

  • Posterior chamber lens:This is the most commonly used type of lens.

    It is inserted into the capsular bag (where the natural lens was previously located) and is fixed there by elastic temples.

  • Anterior chamber lens:If the capsular bag is not preserved, this type of lens can be used. It is inserted in front of the iris and fixed in the anterior chamber angle. Unfortunately, from time to time tissue changes can occur and the inner side of the cornea (the corneal endothelium) can be damaged.
  • Iris-supported lenses:With this type of lens, the actual lens is also located in front of the iris, while the anchors are behind the iris (iris claw lens).