Cataract – Age-related clouding of the lens
A cataract is the clouding of the eye's lens, the crystalline lens responsible for focusing. This clouding leads to impaired vision: decreased visual acuity, photophobia, yellowing of colors, and loss of contrast. It is most often age-related (primary cataract) and sometimes triggered by trauma or a metabolic disease such as diabetes (secondary cataract). Treatment is exclusively surgical and involves removing the diseased lens and replacing it with an artificial lens called an implant.
What is a cataract?
A cataract is a clouding of the lens, the part of the eye that allows focusing.
The progressive opacity of the lens leads to an alteration of light entering the eye and consequently an alteration of visual functions.
Who is affected?
Cataracts are an extremely common condition, most often related to age, and they begin to appear at 60 years old.
The average age for the operation is around 67 in France. After age 80, 2 out of 3 French people will have had the operation.
Symptoms of cataracts
Cataracts impair the amount of light entering the eye. Vision gradually becomes dull and blurry. The symptoms specific to cataracts are:
The yellowing and dulling of colors.
Index myopia – Near vision improves at the expense of distance vision.
Night blindness – Loss of contrast predominant in low light environments.
Photophobia – Exaggerated sensitivity to light.
Decreased visual acuity – Vision deteriorates independently of wearing glasses.
Monocular diplopia – The image is doubled.
Causes and risk factors
The main cause of cataracts is age: we speak of primary, senile, or age-related cataracts.
Some cataracts are triggered by external events; these are called secondary cataracts. The causes are:
Eye injuries: physical shock or radiation
High myopia
Metabolic diseases: primarily diabetes, calcium disorders,…
Previous ophthalmic surgeries (excluding refractive surgery): glaucoma, retina, corneal transplant
Oxidative stress: UV radiation, smoking
Eye inflammations (uveitis)
Certain medications: corticosteroids, gold salts, antiepileptics
How is a cataract diagnosed?
The diagnosis of cataracts is based on a combination of factors:
Visual dissatisfaction that develops gradually.
The decrease in visual acuity measured by the ophthalmologist.
Opacification of the lens demonstrated during clinical examination using a slit lamp (tabletop microscope).
If there is any doubt, the diagnosis can be confirmed by two additional tests:
OCT can reveal an increase in the density of the lens.
OQAS, or aberrometry, quantifies the optical disturbances caused by cataracts.
Differential diagnoses
Concluding that a decrease in vision is linked to cataracts requires having eliminated all other causes of decreased visual acuity.
Therefore, the diagnosis should only be made after a meticulous clinical examination ruling out damage to the cornea, retina, macula and optic nerve.
For greater diagnostic accuracy, it is advisable to supplement the clinical examination with an OCT of the retina and optic nerve.
Evolution and prognosis
Cataracts usually develop slowly and progressively. Vision loss sets in gradually, eventually leading to blindness if left untreated.
In fact, it is the leading cause of visual impairment worldwide!
With proper treatment, cataracts have an excellent prognosis. Recovery after surgery is short and the surgical success rate is over 99%.
Complications of cataracts – What happens if it is not operated on?
The main complication of cataracts is decreased vision and its consequences: loss of independence, falls, social isolation.
Sometimes the cataract increases in size, pushing the iris against the trabecular meshwork, an organ used to regulate eye pressure, leading to glaucoma.
Rarely, so-called "hypermature" cataracts develop spontaneous complications. The capsule containing the cataract can fall out; this is called spontaneous lens dislocation.
Finally, the lens capsule can rupture and cause eye inflammation; this is called phako-antigenic uveitis.
Care to take when one has a cataract
Once a cataract diagnosis is made, the benefit/risk balance must be assessed: treat it or wait. Cataract surgery is almost never urgent.
If there is no impairment in daily life activities, it is best to let the cataract mature and reassess its progress 6 to 12 months after diagnosis.
If you are experiencing visual impairment, there is no need to wait any longer; it is best to have surgery according to your availability and that of the surgeon.
Cataract treatment and surgery
Cataract treatment is always surgical. There is no medication in pill or eye drop form that can reverse or even slow its progression.
Cataract surgery is the most frequently performed surgical procedure in the world, and it is probably also the most well-controlled.
The procedure involves aspirating the diseased lens (cataract) through a 2 mm incision.
Once the cataract is removed, it is replaced with a perfectly clear artificial lens, also called an implant.
Secondary cataract – Posterior capsular opacification
Your vision may become blurry or cloudy again weeks, months, or even years after cataract surgery. This is not unusual. It is called "posterior capsule opacification" or, more commonly, secondary cataract.
This is not a recurrence of the cataract. But because it occurs after cataract surgery and mimics the symptoms, some people call it a secondary cataract.
It occurs when a membrane called the posterior capsule becomes cloudy. It can be helpful to think of the posterior capsule as a transparent pouch. It holds your implant in place. It also held your eye's natural lens in place (which has now become a cataract).
Over time, this membrane has become opaque in contact with the implant, so it needs to be treated.
If you experience blurred vision again, you may need laser surgery. The laser creates an opening in the cloudy capsule and is called a posterior capsulotomy (or YAG laser capsulotomy). This procedure restores clear vision.
Frequently Asked Questions
What is a cataract?
A cataract is an opacity of the intraocular lens that allows focusing: the crystalline lens.
What are the symptoms of cataracts?
The symptoms of cataracts appear gradually: dulling of vision, loss of contrast, yellowing of colors, glare in light, refractive error, then decreased vision.
How to slow down the progression of cataracts?
Unfortunately, there is no proven medical treatment in the form of eye drops or tablets that can slow down the clouding of the lens. However, wearing sunglasses, quitting smoking, and managing diabetes offer some protection if these risk factors are present.
How much does the operation cost?
The costs of cataract surgery are covered by social security and supplemental health insurance. The surgeons at this practice charge a controlled additional fee. Depending on your supplemental health insurance plan, all or part of this additional fee may be covered.
Similarly, in the case of a premium implant correcting astigmatism or presbyopia (toric or multifocal implant), the clinic charges an additional fee. This is because social security considers the inability to wear glasses a cosmetic comfort benefit of the surgery. Some supplemental health insurance plans cover this additional cost, anticipating a subsequent decrease in the cost of optical prescriptions in the years following the procedure. Discuss this with your advisor.