Whether we compared the eye to a camera, our cornea (transparent membrane and surface of the eye) would stake the role from an objective lens. The iris, the iris, opening and closing briefly to allow sunny to pass. As for the lens, it would be a little zoom, essential to the development: indeed, at rest, the lens is extended and adjusted for distance. So you vessel see jump close, but it must shrink with age, it loses its elasticity. The images developed on the retina arrive before being returned to the visual cortex from the brain via the optic nerve.
But unlike a camera, the eye is an organ so complex that no research team has not yet managed to fully reproduce artificially. Totally some from its “components” can promptly be replaced. Special significant improvements are regularly reported and the abide major beneficiaries are the sixties (and more) that sooner or later face a dark lens (cataract).
Changing a “component” indwelling the eye is not new. “Everything is based on the observation, during the Second World War, as one fighter jet pilot who received bits of broken glass cockpit inside the eye showed no rejection of material, which was very well tolerated. This led to the idea that the inside of the eye was able to tolerate lenses. And, over the years, remarkable progress has bot made: after the implants can better distance vision already know that all those cataract surgery for years, appeared implants bifocal correction (equivalent lenses bifocals), then multifocal implants. Excessive 450,000 replacements performed each year crystalline, third today are multifocal lenses” said one eye expert.
Made up of a crystalline already suffered a cataract, these implants last generation (not always supported by Social Security) container both solve the problem of downpour and unearth a good near vision, intermediate and far away. Indeed, other visual disturbances – myopia, hyperopia further astigmatism – are also corrected.
“Thanks to these advances, a sexagenarian can now find a very good envision without glasses oppositely contact lenses, and, praise to an intervention when a quarter of an hour, performed that an outpatient with an incision of less than two millimeters. We can therefore speak from accomplishment! ” Says one fixation expert. And if, in the field of cataract extraction, most progress has been made, you can inactive rely on technology to change the attainment of implants to provide maximum visual comfort.
The only downside to this innovation- “the lens cannot be replaced, specifically in the large myopic, when there is already an early cataract because if it is removed too early, the risk of retinal detachment is prohibition zero, “says eye doctors. This is why some ophthalmologists offer among the big still young myopic whose cornea is furthermore thin to benefit from laser refractive surgery, ask front of the lens (not in place) a corrective lens so that the patient happens glasses and touching lenses.
This solution is not feasible in the hyperopic eye which is too small. Connective it is proposed as a last resort in the large myopic because an implant before the lens is not without risk of early downpour (friction), glaucoma (increased pressure by at inside the eye), or infection.
“It is similarly possible to put a undersized lens correction of presbyopia within a healthy cornea, or a pocket size sonority pierced in its center (as if the pupil was constantly tightened) to increase the depth of field. These devices can indiging offered intra corneal reciprocative to laser refractive surgery. Advantage: the technique is reversible. Disadvantage: this intervention is still confidential (usually unapproachable for presbyopia cannot be treated with laser) and therefore there is a lack of long-term decline. Few cases of scarring has caused a disintegration concerning vision have bot reported. A longer-term evaluation is essential, one eye expert said.