الفهرس 
Optics and designs of multifocal IOLsOnly 14 pages are availabe for public view
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Abstract
The use of Multifocal intraocular lenses (MIOLS) is increasing in practice of cataract surgery because of reduction of spectacle dependency and high level of patient satisfaction. (1) Patient who received bilateral MIOLS obtained better corrected near visual acuity , less limitation in visual function , and less spectacle dependency than monofocal IOLS. (2)
MIOLS have been implanted since 1986, with refractive and diffractive designs. Surgically induced astigmatism was a possible complication . Reduced contrast sensitivity , colour vision , increased glare and haloes were common problems of MIOLS . modern MIOLs can be considered not only for correction of aphakia but also for refractive purposes.(3)
Besides the diffractive type of MIOLs , which produces a second focus for near vision by means of diffraction rings, there is refractive type with 2-7 refractive zones . (4) Diffractive MIOLs provide better near visual acuity , increased contrast sensitivity and less glare disability than refractive type .(5)
With MIOLs , smaller pupil size is correlated significantly with worse near visual acuity (6) , larger pupil size is correlated significantly with better distance visual acuity but with worse near visual acuity . (7)
Although MIOLs can provide near vision, they may increase higher-order aberrations and negatively influence contrast sensitivity. However, the aspherical MIOLs can reduce aberrations and improve contrast sensitivity as compared with the spherical MIOLs .(8)
When choosing a multifocal intraocular lens, the needs of each patient should be taken into consideration ,(9) near visual acuity is significantly better with diffractive type , while distance visual acuity is good with both types but is better with refractive type . New models of MIOLs achieve comfortable distance and near vision .(10)