is the total or partial loss of the eye's natural lens transparency (opacification). A cataract begins when proteins in the eye form clumps that prevent the lens from sending clear images to the retina.
The lens is located inside the eye behind the iris, the coloured part of the eye. Normally, the lens focuses light on the retina, which sends the image through the optic nerve to the brain. However, if the lens is clouded by a cataract, light is scattered so the lens can no longer focus it properly, causing vision problems.
The name derives from the Greek katarraktês, which means "something that falls from top to bottom", to express the idea of a screen that prevents the eye from seeing when the lens becomes opaque.
The chances of developing cataracts increase with age, especially after 60 years, due to the physiological ageing of the lens. This is not, however, a condition that only affects the elderly because there are congenital cataracts, present at birth, and cataracts of different origin such as those due to traumas, those caused by prolonged exposure to ionizing radiation, and those induced by medications used either locally or systemically (e.g. cataracts from cortisone).
Excessive and prolonged exposure to sunlight is another risk factor for the development of cataracts. There are also forms of cataract associated with other eye diseases such as glaucoma, uveitis, or systemic diseases, such as diabetes.
Usually cataracts develop in both eyes but do not form at the same time. The cataract in one eye may be more advanced than the other, causing a difference in vision between eyes.
There is no treatment to prevent or slow cataract progression. In age-related cataracts, changes in vision can be very gradual. Some people may not initially recognize the visual changes. However, as cataracts worsen, vision symptoms increase.
Signs and symptoms of a cataract may include:
• Blurred or hazy vision
• Reduced intensity of colours
• Increased sensitivity to light and glare, particularly when driving at night
• Seeing "halos" around lights
• Increased difficulty with vision at night
• Change in the eye's refractive error, or prescription
• Double vision in a single eye
Diagnosis and Treatment
Cataracts can be diagnosed through a comprehensive eye examination. This examination may include a visual acuity test, slit-lamp examination and retinal exam.
If a cataract minimally affects vision, or not at all, no treatment may be needed. In some cases, changing the eyeglasses prescription may provide temporary vision improvement. When a cataract progresses to the point where it affects a person's ability to carry out normal everyday tasks, the only effective treatment for cataracts is surgery.
Cataract surgery involves removing the lens of the eye and replacing it with an artificial lens. Surgery to remove a cataract is generally very safe and has a high success rate. The phacoemulsification technique is normally used.
Another option is the femtosecond laser or femtolaser which has recently been introduced in cataract surgery.
Once the cataract has been removed, in order to restore a satisfactory vision, an intraocular lens (IOL) or "artificial crystalline lens" is implanted.
This lens is made of biocompatible materials and, once positioned, is fixed inside the eye and does not need to be cleaned or replaced. Modern IOLs may restore a good quality of vision, as long as the other structures of the eye, particularly the retina, are healthy.
In the most modern implantation techniques the IOL can be inserted into the eye through very small incisions (mini-and micro-incision) that do not require any stitches.
Furthermore, the IOL option takes into account the patient’s refractive errors (myopia, astigmatism, hypermetropia, and presbyopia) in order to compensate them, in whole or in part, and reduce or eliminate the need to wear glasses (refractive cataract).
Before and after surgery prophylactic drug treatments are administrated in order to prevent and avoid inflammatory and infectious complications such as postoperative endophthalmitis.
SIFI's surgical division provides ophthalmologists with a complete range of IOLs for mini-incisions, an innovative IOL for surgical correction of presbyopia and disposables for cataract surgery (viscoelastic, saline solution, etc).