Crystalens accommodating intraocular lens
It has been demonstrated that pharmacologic stimulation overestimates the accommodative effort, and thus the results of such measurements may be indicative of the potential of accommodative IOLs; the real life conditions are different.
Ray tracing aberrometry has also been utilized for the objective measurement of accommodation, having as a limitation the difficulty to evaluate aberrations in constricted pupils.Due to the high disparity of the methods that are used there is significant inconsistency in the results of many studies [8, 9].Another source of inconsistency is the fact that several studies in order to evaluate accommodative response of the IOLs use pharmacologic stimulation of accommodation with pilocarpine, or pharmacologic relaxation with cyclopentolate, or both in different time points.Despite the difficulties in measuring accommodation, accommodative IOLs represent the future in the attempt to successfully “cure” presbyopia.The restoration of near vision in older individuals that have entered the presbyopic age is considered one of the major challenges in refractive surgery during the last decade.There are three principal approaches for the achievement of good near and far vision concomitantly.
The first is the establishment of a functional multifocality in the visual system, the second is the establishment of a binocular divergence with one eye focused for far vision and the other for near (i.e., monovision), and the third is the attempt to restore normal accommodation.
This component of pseudoaccommodation is called pseudophakic accommodation, while the static component is called pseudophakic pseudoaccommodation.
Considerable amount of data proves that pseudophakic IOLs can respond to ciliary body contraction with axial displacement.
Surgical ways include corneal procedures (i.e., laser surgery on the cornea, thermokeratoplasty, and implantation of corneal inlays) and intraocular procedures that include cataract surgery or refractive lens exchange with the implantation of multifocal intraocular lenses or monofocal lenses with refractive target monovision.
The third principal approach for reinstatement of near vision, restoration of accommodation, can be achieved only with surgical ways.
Apparent accommodation has been assessed in several studies by means of several objective and subjective methods.