Brief overview
- Symptoms: increasing deterioration of vision, sensitivity to glare, seeing “as if through a veil/fog”.
- Causes: mostly aging processes of the eye, sometimes also other diseases (e.g. diabetes mellitus, eye inflammations), eye injuries, congenital eye malformations, radiation exposure, heavy smoking, medication
- Diagnostics: among other things patient interview, various eye examinations (e.g. by means of slit lamp), if necessary further examination in case of suspicion of an underlying disease (like diabetes)
- Treatment: surgery
- Prognosis: generally good chances of success with surgery
Cataract: Symptoms
If your vision becomes cloudy and the world seems to disappear behind a veil, this could be a sign of the eye disease cataract. “Gray” because the lens turns a grayish color as the disease progresses, making it cloudy. The name “cataract” is derived from the fixed gaze that sufferers have when they are (almost) blinded by the eye disease.
The medical term for cataract comes from the Greek and means “waterfall”. In the past, it was assumed that clotted fluid in the eye caused the clouding of the lens.
Cataract: Symptoms in the course of the disease
This fog becomes denser over time and spreads to the entire visual field as the disease progresses. Colors, contrasts and contours gradually fade and seem to merge. Spatial perception and thus orientation ability deteriorate.
Single and complete failures of the field of vision, as they occur in glaucoma, do not occur in cataracts.
As the disease progresses, cataracts present symptoms that can greatly burden those affected in their daily lives. These include:
- marked sensitivity to glare (e.g. in bright sunlight or flashlight)
- indistinct optical perception
- poorer light-dark adaptation
- strain when reading or watching television
- limited spatial vision
- insecurity in road traffic
These symptoms may vary in severity from patient to patient. They also do not necessarily have to occur (all).
Finally, late-stage cataracts make normal everyday life almost impossible: visual performance can deteriorate so dramatically within a short time that it is tantamount to blindness.
Cataract: Symptoms often not recognized or misinterpreted for a long time
Another problem is that many people with cataracts initially ignore the symptoms, overplay them or attribute them to other causes such as fatigue. Especially in the case of senile cataracts, which develop as a result of the natural aging process, the symptoms are often attributed to the age-related deterioration of the eyes – and not to a manifest eye disease such as cataracts.
Cataract: Relatives should watch out for signs
Precisely because those affected often misjudge or deny the deterioration in vision, it is important that relatives know the symptoms of cataracts and interpret them correctly. In the early stages of the disease, those affected become more unsteady in their usual activities, for example when driving or reading. This is noticeable, for example, in the fact that patients often show a strained facial expression during these activities.
In the later stages, the deterioration in vision can become so severe that patients often miss holding something when it is handed to them or when they want to pick something up themselves. In addition, it takes them a long time to find their way around an environment in which they are unfamiliar. That is why they often avoid unfamiliar places.
Congenital cataract: symptoms
Children can also develop cataracts. Doctors then speak of infantile or congenital cataract. The clouding of the lens can already exist at birth or develop during the first years of life. The first sign is often that children begin to squint (strabismus).
Parents should not ignore this, but should definitely take it seriously. If left untreated, the loss of visual acuity can impair the development of the visual system, which is particularly sensitive to disturbances in the first months of life: If a baby’s cataracts are not recognized and treated, they can develop into what is known as amblyopia.
This amblyopia can no longer be corrected by the time the child reaches puberty at the latest. Therefore, see a doctor immediately if your child shows signs of cataracts!
Cataract: Causes and risk factors
In the vast majority of cases, cataracts are age-related. However, it can also have other causes such as metabolic disorders, other eye diseases or eye injuries. Read more below:
Natural aging process
With age, the flexibility of the eye’s lens naturally decreases, which can result in lens clouding. Therefore, about 90 percent of all cases of cataracts are senile cataracts. This senile cataract occurs around the age of 60. According to statistics, almost half of 52- to 64-year-olds have cataracts without knowing it. This is because at the beginning of the disease, no visual disturbance is often noticeable. From the age of 65, almost everyone has a clouding of the eye lens.
Diabetes mellitus
In diabetes mellitus, the amount of sugar in the eye fluid (and blood) is increased. Excess sugar (glucose) is deposited in the lens, causing it to swell. As a result, the arrangement of the lens fibers shifts, and the lens becomes cloudy. Doctors refer to this as cataracta diabetica.
In pregnant women with diabetes mellitus, the child can already develop a cataract in the womb.
Other metabolic disorders
In addition to diabetes, other metabolic disorders can also promote a cataract. These include, for example:
- Calcium deficiency (hypocalcemia)
- Hyperparathyroidism (overactivity of the parathyroid gland)
- Excess ferritin in the blood (ferritin is an iron storage protein)
- Galactosemia (a congenital disorder in the utilization of the sugar galactose contained in breast milk)
Eye diseases
Eye injuries
A bruise to the eyeball from a punch or a tennis ball can cause a cataract, as can, for example, a puncture injury or a foreign body that has penetrated deeply into the eye. Such injury-related cases of cataracts are grouped under the technical term cataracta traumatica.
Congenital eye malformations
If cataracts are congenital (cataracta congenita), there may be two reasons:
- Genetic defect: About 25 percent of all congenital cataract diseases are due to a genetic defect that leads to a malformation of the eye and thus to a clouding of the lens.
- Infectious diseases during pregnancy: Certain infections in pregnant women (rubella, toxoplasmosis, herpes) can cause the child to be born with a cataract.
Other causes
Lens metabolism defects, malnutrition, heavy smoking, radioactive radiation and ultraviolet light (UV light) can also be triggers for a cataract. Very rarely, medications or poisoning are the reason for lens clouding.
Cataract: Examinations and diagnosis
A precise examination by an ophthalmologist is necessary for the diagnosis of cataracts.
Medical history
Eye examinations
This is followed by various eye examinations. For this purpose, sometimes first the pupil is dilated with the help of special eye drops. The following examinations help in the diagnosis of cataracts:
- Brückner test: In this examination, the doctor shines a light through the eye. Since the retina reflects part of the light, lens opacities become visible as dark spots.
- Slit lamp examination: The slit lamp is a microscope with a light source that can be swiveled to either side. The focused, slit-shaped beam of light penetrates the transparent parts of the eye. This also allows the doctor to examine the retina at the back of the eye to see what type of cataract is present and what might be causing it.
- Corneal exams: The doctor can measure the thickness of the cornea (pachymetry) and image its top and back surfaces using computerized techniques. The latter reveals whether the cornea is evenly curved and whether the cell layer that supplies the cornea and ensures its transparency is in order (determination of endothelial cell density).
- General vision test: Routinely, the ophthalmologist also checks the general vision, for example by means of vision charts, and whether other eye diseases are present.
If cataracts are already far advanced, the clouding of the lens can already be seen with the naked eye.
Other examinations
Cataract: Treatment
Cataracts can only be effectively treated by surgery (cataract surgery). This involves removing the cloudy lens and replacing it with an artificial lens. Nowadays, the surgeon usually does not remove the entire lens, but leaves the lateral and posterior capsule in the eye.
Cataract surgery is the most common eye surgery. Worldwide, the surgery is performed more than 100 million times a year.
The operation is a so-called microsurgical operation, i.e. it is performed with an operating microscope. This is possible both in a hospital and in an ophthalmologist’s office. The inserted artificial lens remains in the eye for life, so it does not need to be replaced after some time.
Cataract surgery: When is it necessary?
When cataract surgery is performed depends on various factors. The doctor and the patient jointly determine the time of surgery.
A role in the decision is played above all by the subjective perception of the visual impairment. If an affected person feels strongly impaired by the cataract in everyday life and in professional life, this speaks for an operation.
In some professions, a certain visual performance is even a mandatory requirement, for example for pilots and professional drivers. In such cases, cataract surgery is often necessary at an early stage of the disease. The subjective perception of visual performance does not play a role here.
If possible, the patient’s fears regarding the eye surgery are taken into account when deciding for or against surgery. However, if a cataract threatens blindness, surgery should be performed even despite such fears.
A congenital cataract should be operated on immediately after diagnosis. Only then will the child have a chance to learn to see properly.
Lenses used
The intraocular lens used in cataract surgery is made of a plastic material. It must have exactly the same refractive power as the removed endogenous lens. The doctor calculates the appropriate lens power before the operation by measuring the length of the patient’s eye with an ultrasound device and determining the refractive power of the cornea.
The artificial lenses used differ in terms of implantation site, material and their optical principles.
Differences in implantation site
Depending on the implantation site, a distinction is made between anterior chamber lenses, posterior chamber lenses and iris-supported lenses.
- Posterior chamber lenses (PCL) are inserted into their own capsular bag, which is located behind the iris. If there is no capsular bag left, as in intracapsular cataract extraction, the lens is attached to the iris or sclera of the eye with two sutures.
- Iris-supported lenses (iris clip lenses) are attached to the iris with small temples. Since this often injures the cornea, such lenses are no longer used. Already implanted iris-supported lenses are in many cases replaced by posterior chamber lenses.
Differences in lens material
Intraocular lenses made of silicone or acrylic are used in small incision cataract surgery because these lens materials are foldable. These artificial lenses are inserted into the capsule in a folded state, where they then unfold themselves. They are used exclusively as posterior chamber lenses.
An acrylic lens has a higher refractive index than a silicone lens and is therefore slightly thinner.
Dimensionally stable lenses made of polymethyl methacrylate (PMMA, Plexiglas) can be used both as anterior chamber lenses and as posterior chamber lenses. In this case, a somewhat larger incision is required for implantation.
Differences in the optical principles
- Monofocal lens: Like regular glasses, it has only one focal point. It allows sharp vision either in the distance or in the near. Before the operation, the patient must decide whether he or she would prefer to live without “distance glasses” but with reading glasses after the operation, or vice versa. The appropriate power of the artificial lenses is selected accordingly.
- Multifocal lens: It provides good visual acuity for both distance and near vision. Patients then no longer need glasses for more than 80 percent of daily tasks. Multifocal lenses have two disadvantages, however: Contrasts are seen less sharply, and the eye becomes more sensitive to glare.
Surgical methods
There are various methods of lens implantation to eliminate lens opacity. Which one is used in each case depends on individual conditions and the stage of the disease.
Intracapsular cataract extraction (ICCE)
In this form of cataract surgery, the lens including capsule is removed from the eye. This requires an eight to ten millimeter incision through the cornea. The lens is then frozen with a special cold pen and removed from the eye.
Intracapsular cataract extraction is usually necessary only at an advanced stage of the disease.
Extracapsular cataract extraction (ECCE)
In extracapsular cataract extraction, the surgeon opens the anterior lens capsule with an incision about seven millimeters long and removes the lens nucleus without crushing it. The artificial lens is now inserted into the intact capsule.
This surgical method is gentle on the cornea. Therefore, it is mainly used when a far advanced cataract has already damaged the thin, innermost layer of the cornea (corneal endothelium).
Phacoemulsification (Phaco)
In phacoemulsification, the cornea is opened with an incision about 3.5 millimeters wide. Then, using ultrasound or a laser, the doctor dissolves and aspirates the lens nucleus. The artificial replacement lens is now inserted into the intact shell of the lens (capsular bag): it is pushed folded through the tiny opening and unfolds in the capsular bag itself. Two semi-circular elastic clips on the edge of the lens ensure a secure hold in the capsular bag.
Cataract surgery procedure
Cataracts usually occur on both sides. However, only one eye is operated on at a time. As soon as this eye has healed, the second eye is operated on.
The procedure usually takes less than 30 minutes.
Outpatient surgery, local anesthesia
Cataract surgery is usually performed on an outpatient basis under local anesthesia. In most cases, the administration of suitable eye drops is sufficient for anesthesia. Alternatively, a local anesthetic can be injected into the skin next to the eye to be operated on. In this way, the entire eyeball becomes painless and cannot be moved. The doctor may also give you a mild sedative before the surgery.
Throughout the surgery, your circulation will be monitored with the help of a blood pressure machine, by measuring your oxygen saturation, or with the help of an EKG.
After the operation, the operated eye will be covered with an ointment dressing. You will need to stay in the hospital or doctor’s office for some time for monitoring. If there are no complications, you will be allowed to go home after a few hours. In the following period, regular check-ups by the attending physician are necessary.
What you should keep in mind after the procedure
You can still have light food and drinks on the day of the operation. You can usually take your usual medication as usual, but you should discuss this with your doctor beforehand. This is especially advisable if you need diabetes medication or blood thinning medication.
As long as the operated eye is covered with a bandage and the surgical wound has not yet healed, you should take care when showering and washing that the eye does not come into contact with soap.
Physical exertion, swimming, diving, cycling and sauna visits should be avoided in the first period after cataract surgery. The same applies to activities that involve a lot of dirt or dust. You can usually read and watch television again after one week.
You can usually have new glasses fitted four to six weeks after cataract surgery. It is not advisable to do so at an earlier stage, as the eye must first get used to the new lens.
If you notice the following signs some time after cataract surgery, you should see an ophthalmologist:
- worsening of visual acuity
- increased redness of the eye
- pain in the eye
Risks and complications of the surgery
Capsule tear
If the posterior capsule of the lens tears during surgery, complications may arise. Behind the lens of the eye is the so-called vitreous body. It consists of a gel-like, transparent mass and presses the retina, which is located in the back of the eye, against its base. If the vitreous substance escapes via a lens tear, there is a risk of retinal detachment.
This risk occurs in about six to eight percent of intracapsular surgeries; in contrast, capsular tears rarely occur in extracapsular surgery.
Bacterial infection
Very rarely, during intracapsular cataract surgery, bacteria enter the interior of the eye and cause inflammation (endophthalmitis). This can cause the affected eye to go blind.
Bleeding
During cataract surgery, there may be an increase in pressure inside the eye that can cause blood vessels to burst. Bleeding within the eye (intraocular) or within the capsule (intracapsular) is the result. However, they are very rare: Such bleeding occurs in less than one percent of all cataract surgeries.
Corneal curvature
In the extracapsular surgical method, the incision causes a slightly greater corneal curvature than before the operation. However, this usually regresses on its own within a few weeks.
“After-cataract
With the help of a laser or another surgical procedure (similar to cataract surgery), these clouded lens portions can be quickly removed with minimal risk. Vision improves again afterwards.
Cataract: Course of the disease and prognosis
Cataracts progress slowly but steadily if left untreated – vision deteriorates until the affected person goes blind in the affected eye. This can only be stopped by surgery. The chances of success of the operation depend largely on the cause of the clouding of the lens:
A senile cataract can usually be completely cured by surgery – most patients regain 50 to 100 percent of their visual acuity.
The surgical result is usually less good in patients whose cataract is caused by another eye disease, such as glaucoma, age-related macular degeneration (AMD) or diabetes-related retinal disease (diabetic retinopathy). Affected individuals should discuss with their doctor prior to the procedure what improvement in visual acuity is likely to be achieved with the procedure.
Also in the case of cataract due to other causes, the prognosis after surgery is often worse than in the case of senile cataract.
Cataract: Prevention
Protecting the eye
For example, you should always wear protective eyewear when performing activities that could injure the eye (such as grinding or drilling).
When spending time in the sun (especially skiing), a good pair of sunglasses will protect your eyes from dangerous UV radiation. You should also wear protective glasses when in the solarium.
Attend preventive care appointments
Visit your eye doctor every 12 to 24 months starting at age 40 to have your vision checked. A regular eye test can detect cataracts even when symptoms are barely noticeable.
If you want to become pregnant, you should check your vaccinations beforehand and have them refreshed if necessary. This can prevent infections that can cause cataracts in the baby (such as rubella).
