Advances in Cataract Surgery

Majed Alkharashi; Walter J Stark; Yassine J Daoud


Expert Rev Ophthalmol. 2013;8(5):447-456. 

In This Article

Accommodating Lenses

The Crystalens (Bausch & Lomb, Aliso Viejo, CA, USA) is the only FDA approved 'accommodating' lens to correct presbyopia in patients with cataracts. The Crystalens has undergone several modifications since the original model (AT-45). It has silicone optic and two flexible, hinged plate haptics. The latest models (HD and AO) have a central 1.5 mm blended bispheric optical zone to enhance near vision.[39] The Crystalens has been shown to have better uncorrected near visual acuity than a monofocal lens.[39] Although it was thought that the Crystalens mode of action is through accommodation, several studies have failed to demonstrate a significant accommodative shift. Indeed, the Crystalens have been shown to have poorer uncorrected near visual acuity than the multifocal lenses. Thus, many Crystalens surgeons may aim for -0.50 D to -0.75 D of myopia in the nondominant eye to induce 'mini-monovision' in their patients.[40–42] Another drawback of the Crystalens has been issues with tilting and decentration of the lens caused by capsular contraction and fibrosis.[43] On the other hand, there are less complains of glare and halos from Crystalens than from the multifocal lenses. Thus, Crystalens is a good option for patients who are willing to accept some compromise in near vision but have a low threshold for glare and halos that may be present with multifocal lenses.[44]

One of the new accommodating lenses currently undergoing FDA trials is the Synchrony accommodating IOL (Abbot Medical Optics, Abbott Park, IL, USA). The Synchrony IOL consists of a foldable, single piece, dual-optic system. A spring haptic joins the high plus anterior optic to a minus powered posterior optic.[45] During attempted distance vision, the two optics are close together. Near vision is achieved by attempted accommodation with subsequent decrease in capsular bag and zonular tension. This in turn moves the front optic forward and changes the focal point to intermediate or near vision. In a small prospective study, the Synchrony lens was shown to have equivalent uncorrected-distance and uncorrected- near visual acuity to the ReSTOR lens while providing better uncorrected-intermediate visual acuity and less halos and glare.[46]

Another promising technology is the three-piece Light Adjustable Lens (Calhoun Vision Inc., Pasadena, CA, USA) made of a photosensitive silicone material. Within two weeks post-operatively, the residual refractive error could be corrected by shining an ultraviolet light on the IOL through a dilated pupil to change the shape of the lens. The Light Adjustable Lens corrects spherocylindrical errors as well as presbyopia by creating a small near zone add according to the pupil diameter.[47–49]