The goal of cataract therapy is to improve vision, which can only be achieved by surgery in cases of manifest cataract. In cases of severely impaired vision or at the patient’s request, cataract surgery is performed. In this case, the clouded lens of the eye is surgically removed, which can usually be done on an outpatient basis under local anesthesia (local anesthetic). The duration of the surgery is only about 10-20 minutes.
Lens Extraction
In extracapsular lens extraction (lens removal), part of the capsular bag of the lens is preserved and can be used to anchor the artificial lens, whereas in intracapsular lens removal, the entire capsular bag is also removed. The lens is then attached to the iris (iris skin) or via stirrups in the chamber angle. The method of choice today is extracapsular removal, since this operation preserves part of the capsule as a natural barrier between the anterior and posterior segments of the eye. For this purpose, the anterior lens capsule is opened in a circular fashion (capsulorhexis) and the lens contents (lens nucleus and lens cortex) are crushed and aspirated by means of phacoemulsification (from Gr. phakos (eye) lens), i.e. by a cannula stimulated with ultrasound. The lens is then implanted into the empty capsular bag. For further details see “Cataract surgery“. In the simultaneous presence of primary narrow-angle glaucoma (POAG) and cataract (cataract), lens extraction can lead to a significant reduction in intraocular pressure (IOP; intraocular pressure). This is associated with a reduction in antiglaucomatous therapy or avoidance of trabeculectomy (incision of the trabecular meshwork, i.e., creation of a fistula, to improve aqueous humor outflow).
Lens implantation
For lens implantation, artificial blue filter lenses (for possible AMD prophylaxis?/prophylaxis of age-related macular degeneration) made of plastic are used. A distinction is made between posterior chamber lenses – after extracapsular lens extraction and anterior chamber lenses – after intracapsular lens removal. An implanted lens remains in the eye for the rest of its life and does not need to be renewed or replaced.
Since artificial lenses are rigid and cannot adapt to different distances like a natural eye lens, glasses must be worn even after lens implantation, especially for reading.
Further notes
- Artificial lens implantation in older women was associated with a reduced mortality risk (risk of death) in a large prospective observational study (1.52 deaths per 100 person-years versus 2.56 deaths per 100 person-years; adjusted hazard ratio 0.40, 95 percent confidence interval 0.39 -0.42; highly statistically significant).
