The cristalline lens is a clear lens that is located inside the eye, it allows image focus and a net view at no matter what distance in young patients with no refractive errors (no myopia, hypermetropia nor astigmatism). With the ageing process, the lens undergoes structural changes: physiologically, we become presbyopes and pathologically, we can develop a cataract follwing the loss of lens transparency. Visual acuity drops for far and near distances and cannot be corrected by spectacle use.
Cataract is also often present accompanying other ocular diseases (chronic inflammation for example), and systemic diseases or treatments (radiotherapy and corticotherapy for example).
Nowadays it is very rare to have a cataract so important that it is visible to the naked eye: in those rare cases, the pupil presents a white or grey color in place of its normal black color. More often, cataract can only be seen upon slit lamp examination by an ophthalmologist. According to the degree and localization of the cataract we can classify cataracts as nuclear, cortical, cortico-nuclear, sub capsular or total cataract (white or brown).
When visual impairment becomes important, the only possible treatment is cataract surgery. This consists of extracting, by way of a small incision, fragmented segments of the opacified lens, keeping the surrounding transparent tissue (the lens capsule). At the end of the procedure, an intra ocular implant (artificial lens) is placed inside the lens capsule. Normally, this procedure is sutureless and can be done under local topical anesthesia as an outpatient procedure. On the months following the intervention, eye drops are the chosen treatment and spectacle prescription is made.