Related articles: Cataract
Definition
The cataract is the opacification of the crystalline lens, a sort of transparent lens placed between the iris and the vitreous body in order to focus the light rays on the retina.
Different forms of cataracts arise with aging, following alterations in the chemical composition of the crystalline lens that reduce its transparency and make it opaque. In addition to advanced age, additional risk factors include: direct eye trauma (including the effects of intense heat and chemical burns), smoking, alcohol abuse and excessive exposure to infrared or ultraviolet radiation. Some ocular and systemic diseases, such as diabetes, and some drugs, including corticosteroids and chemotherapy, can also predispose to opacification of the lens. Some forms of cataract, on the other hand, are congenital, therefore present from birth or from the first months of life. These forms can be sporadic or consequent to metabolic diseases (eg galactosemia) or to chromosomal anomalies. Furthermore, congenital cataracts can be the consequence of intrauterine infections (eg rubella) or other diseases that occur during gestation and affect the unborn child.
Most common symptoms and signs *
- Tinnitus
- Tinnitus
- Halo around the light
- Night Blindness
- Movable bodies
- Fotofobia
- leukocoria
- Nystagmus
- Misaligned eyes
- Reduced vision
- scotomas
- Double vision
- Blurred vision
Further indications
Cataracts generally develop slowly over the years. The first symptoms can be constituted by the less vivid perception of colors (loss of contrast), by glare (halos and flashes around the lights) and by hypersensitivity to light (photophobia). In addition to these symptoms, with the gradual becoming opaque of the lens, there is a blurring of the painless sight and one begins to see less, so that the prescription of the glasses requires frequent changes. The extent of obfuscation depends on the site (central nucleus or posterior lens capsule) and on the extent of opacity. Rarely, there may be a doubling of vision. Furthermore, it may happen that in the early stages of cataract patients are able to see better closely, while the view from afar gets worse (due to variations in the refractive index of the lens). As regards, instead, the congenital cataract, besides the visual difficulties of the child, we will have leukocoria (white aspect of the pupil) and oscillatory movements of the eyes (nystagmus). As with the other cataracts, the opacity of the congenital lens obscures the vision.
The diagnosis is made with an ophthalmological examination, complete with slit-lamp examination. The therapy involves the surgical removal of the cataract and the positioning of an intraocular lens instead of the opaque lens.
