A cataract refers to the progressive opacification of the crystalline lens, the natural lens located inside the eye. Very common with age, it causes decreased vision, glare, reduced contrast and, eventually, significant difficulty in daily life. Julien Gozlan, M.D., ophthalmologist in Paris 16, explains here what this condition is, how it manifests, why it occurs and when treatment may be considered.
What is a cataract?
A cataract is the progressive loss of transparency of the crystalline lens. Normally, this lens allows light to pass clearly through to the retina. When it becomes opaque, light is scattered or blocked, resulting in blurrier, duller and less contrasted vision.
It is neither a membrane that forms on the eye nor a painful disease. In the vast majority of cases, it is a natural aging process of the crystalline lens. Over time, its proteins undergo changes, aggregate and lose their transparency.
The role of the crystalline lens in vision
To fully understand this visual disorder, it is important to recall the role of the crystalline lens in vision quality. This natural lens allows:
- focusing light onto the retina;
- providing part of the accommodation, particularly for near vision;
- maintaining a clear, sharp and well-contrasted image.
In young adults, the crystalline lens is flexible and transparent. With age, it becomes more rigid, which first causes presbyopia, and then it may progressively lose its transparency.
What are the main symptoms of a cataract?
Symptoms generally appear slowly. This gradual progression explains why many patients adapt for some time before consulting an ophthalmologist.
Hazy or blurred vision
The most common sign is less sharp vision, as if looking through a dirty or fogged-up window. The patient notices that objects are less defined, fine details become harder to distinguish and reading requires more effort.
Glare and light halos
The abnormal scattering of light within the opaque crystalline lens often causes glare, particularly when facing the sun, car headlights or bright lighting. Some patients also describe light halos, especially in the evening or at night. These symptoms are particularly troublesome for nighttime driving.
Reduced contrast and less vivid colors
This opacification can give the impression that the world appears duller. Contrasts are less pronounced, colors seem more yellowish or less vibrant, and certain tones become harder to differentiate.
Difficulty with daily activities
As it progresses, it can interfere with simple activities:
- reading and screen work;
- driving, especially at night;
- recognizing faces;
- precision tasks and leisure activities.
Initially, a new pair of glasses may sometimes slightly improve visual comfort, but this does not treat the underlying cause when the opacification progresses.
How does a cataract progress?
Progression is most often slow, over several months or several years. At first, the discomfort is moderate. Then vision gradually becomes blurrier, duller and more sensitive to light.
There is currently no eye drop or medical treatment capable of restoring the crystalline lens to its original transparency. When the impairment truly progresses, management relies on surgery.
What causes cataracts?
The causes are multiple. The most common is the natural aging of the crystalline lens, but other factors can promote earlier onset or more rapid progression.
Age
This is the primary factor. Over time, the fibers of the crystalline lens undergo changes and become more opaque. This is why the condition is particularly common after the age of 60 or 65.
Sunlight and environmental factors
Chronic exposure to ultraviolet rays (UV) without protection can accelerate the degradation of crystalline lens proteins. Smoking also increases oxidative stress and promotes ocular aging, which can contribute to earlier onset.
Diabetes and certain systemic diseases
Diabetes is a significant risk factor. Excess sugar alters the metabolism of the crystalline lens and can accelerate its loss of transparency. Other conditions, such as certain inflammatory or metabolic diseases, can also play a role.
Medications, particularly corticosteroids
Prolonged treatment with corticosteroids, whether taken orally, inhaled or applied topically, is known to promote cataract development. The risk depends on the cumulative dose, the duration of treatment and the patient's predisposition.
Trauma and specific forms
There are also specific forms:
- traumatic, following a direct blow to the eye;
- congenital, present from birth;
- secondary, occurring after another ocular surgery or in certain inflammatory contexts.
Are both eyes always affected by cataracts?
Most often, the condition is bilateral, but it does not necessarily progress at the same rate on both sides. One eye may be more affected than the other for several months or even several years. This asymmetry sometimes explains why the condition is discovered late.
How is a cataract diagnosis confirmed?
The diagnosis is based on a comprehensive eye examination. Observation of the crystalline lens with a slit lamp confirms the opacification and specifies its type: nuclear, cortical or posterior subcapsular.
The examination also allows assessment of the overall condition of the eye. If retinal involvement is suspected, a macular OCT may be useful to look for another associated cause of visual decline. In some patients, a macular condition such as AMD may also influence the management strategy.
When should surgery be considered?
The decision to operate depends primarily on the impact on quality of life. Surgery may be discussed when visual impairment interferes with reading, driving, work, leisure activities or daily comfort.
The procedure is described in detail on the page dedicated to cataract surgery. The choice of the implanted lens is explained in the article dedicated to cataract implants.
FAQ: symptoms, causes and management
Is a cataract only related to age?
Age is the most common cause, but sunlight, smoking, diabetes, certain corticosteroid treatments or ocular trauma can promote earlier onset.
What are the first symptoms of a cataract?
The first signs are often hazy vision, glare from headlights at night, reduced contrast and difficulty reading.
Is a cataract painful?
No, it is usually painless. In case of pain, significant redness or sudden vision loss, you should consult promptly to rule out another ocular condition.
Can glasses be sufficient?
Initially, a new prescription may sometimes slightly improve comfort. However, glasses cannot restore the transparency of the crystalline lens. When the condition progresses, only surgery can provide a lasting solution.
Can its onset be slowed down?
A cataract cannot be entirely prevented, but wearing sunglasses that filter UV rays, quitting smoking, controlling diabetes and having regular eye examinations can help slow its progression.
Are both eyes always affected?
Most often, both eyes eventually become affected, but not at the same rate. One eye may be more affected than the other for a long time.
Can it occur at a relatively young age?
Yes. Although this condition is more common after the age of 60, it can appear earlier in cases of diabetes, high myopia, prolonged corticosteroid treatment, ocular trauma or congenital forms.
When should you seek a consultation?
You should seek a consultation as soon as you experience hazy vision, unusual glare, reduced contrast or difficulty with daily activities, even if the progression seems slow.
When to consult Julien Gozlan, M.D.?
If you experience decreased vision, unusual glare, duller vision or increasing difficulty despite your glasses, a comprehensive assessment will help determine the origin of the problem and evaluate the most appropriate management.
Julien Gozlan, M.D., ophthalmologist in Paris 16, performs a thorough examination of the crystalline lens and the retina to distinguish what is related to this opacification from what may be linked to another associated ocular condition.
📍 Consultation at the Paris – Auteuil Ophthalmology Practice
Julien Gozlan, M.D. welcomes you at the Paris – Auteuil Ophthalmology Practice to assess your vision, confirm or rule out a cataract diagnosis and guide you toward the most suitable management for your needs.
Book an AppointmentFurther reading
- Cataract surgery: procedure details and postoperative course.
- Cataract implants: understanding the different visual options.
- Secondary cataract: vision loss after surgery and YAG laser treatment.