presbyopia


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presbyopia

a progressively diminishing ability of the eye to focus, noticeable from middle to old age, caused by loss of elasticity of the crystalline lens

Presbyopia

 

diminution of the power of accommodation of the eye due to advancing years. Presbyopia occurs as a result of sclerosing of the crystalline lens, which is unable to increase its curvature to the limit when there is a maximum tension (accommodation); the result is that its refractive power decreases, and the ability to see objects close to the eye is impaired.

Presbyopia begins at age 40 to 45 when eye refraction is normal. When myopia is present, it begins later, and with hyperopia, it comes on earlier. Treatment consists in appropriate selection of glasses for reading and close work. Persons 40 to 45 years of age with normal refraction need a plus lens of 1.0 to 1.5 diopters for reading at a distance of 33 cm. Every five years the refractive power of the lens is increased by 0.5 to 1 diopter. Corresponding corrections in the lens power are made for myopia and hyperopia.

presbyopia

[‚prez·bē′ō·pē·ə]
(medicine)
Diminished ability to focus the eye on near objects due to gradual loss of elasticity of the crystalline lens with age.
References in periodicals archive ?
The safety of this approach has been established by over 50 years of corneal research and the company believes that the recent advances in lasers and metrology will allow the creation of precision implants and the predictable correction of presbyopia.
But with age, the lens hardens and loses its elasticity, and the ciliary muscles that control the lens weaken, all leading to presbyopia, or farsightedness caused by an inability to focus on nearby objects.
With Dailies Total1 Multifocal, Alcon has designed a unique contact lens that answers to the increased need for comfort and the expectation of a seamless visual experience of people with presbyopia.
Presbyopia is a manifestation of the general aging process of crystalline lens due to its unique status as closed biological system in which new cells continue to grow while old cells remain.
The findings reinforce the need for presbyopia correction programs for women - a group that often has greater unmet vision needs in developing countries.
TRP's product for presbyopia is Blur Relief Eye Drops.
In addition to the cataract procedures, the device can perform the INTRACOR presbyopia treatment, CUSTOMFLAP Lasik flaps, and the therapeutic indications, CUSTOMSHAPE.
IOLs, or permanent lenses, have become an increasingly popular solution for people with presbyopia, with or without cataracts, who want to rid themselves of glasses permanently.
Unlike the most common vision problems that involve the shape of the eyeball - farsightedness, nearsightedness and astigmatism - presbyopia occurs naturally with advancing age, as the lens in the eye becomes less flexible.
Presbyopia sufferer Deborah Nanson, aged 54, of Coventry, said: "In my early 50s I would be reading a newspaper while waiting for a bus, and worry-ingly would be unable to see either the fine print of the paper or the number of the approaching bus.
Early onset of presbyopia, retinal lesions, sunburn of the cornea (called photokeratitis) and, possibly, the risk of AMD, have also been linked to long-term sun exposure.
5% cited a decline in or the loss of vision, followed by presbyopia (49.