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Ophthalmic lenses
Published in Pablo Artal, Handbook of Visual Optics, 2017
Intraocular lenses had been implanted since 1999 in order to correct high ammetropies, without removing the eye lens. This lens is called a phakic intraocular lens, since the eye lens remains in the eye. Naturally, an aphakic eye with an intraocular lens, cannot accommodate, like in very old people. Presently, bifocal or multifocal intraocular lenses are being implanted, to allow clear near vision, but many practical problems still have to be solved to find a perfect multifocal intraocular lens.
Biometric Factors Associated with the Visual Performance of a High Addition Multifocal Intraocular Lens
Published in Current Eye Research, 2018
Joaquín Fernández, Manuel Rodríguez-Vallejo, Javier Martínez, Ana Tauste, David P Piñero
Standards for reporting results achieved with multifocal intraocular lens (MIOLs) have been defined in order to compare results among different MIOLs.1 These standards include the methodology of plotting and summarizing results about safety, efficacy, and predictability. However, despite these standards being quite useful for comparing results among MIOLs, they fail in terms of including information about how eye parameters can affect the performance achieved with a particular MIOL. It has been previously reported that variations in eye characteristics can affect the performance achieved with a specific MIOL. Some of these parameters include angle kappa (related to the presence of dysphotopsia),2,3 corneal spherical aberration,4,5 regular corneal astigmatism,6,7 corneal irregular astigmatism,8,9 and effective lens addition.10–12 The literature is full of studies reporting results with several MIOLs according to the standards,13–24 but the influence of biometric factors on the performance of each particular MIOL according to the characteristics of the patient is still not clear. The main aim of this study was to evaluate the performance of a high addition MIOL by means of computing the area under the visual acuity defocus curve (VADC)25 and correlate it with several biometric parameters.
Clinical Efficacy of Pinhole Soft Contact Lenses for the Correction of Presbyopia
Published in Seminars in Ophthalmology, 2019
Si Yoon Park, Young Joon Choi, Ji Won Jung, Moonjung Choi, Eung Kweon Kim, Kyoung Yul Seo, Tae-Im Kim
Several approaches for presbyopia correction have been extensively studied. Possible surgical procedures include monovision photorefractive keratoplasty, laser in situ keratomileusis (LASIK), presbyopic LASIK, lens-based procedures with cataract extraction and multifocal intraocular lens (IOL) or monovision IOL implantation, and intracorneal inlay insertion into corneal pockets. These procedures partially alleviate the discomfort caused by presbyopia, although some limitations remain unresolved.6–10 Nonsurgical methods are generally attempted first and include the prescription of multifocal glasses and multifocal contact lenses.11–13
Standard Results and Contrast Sensitivity Reestablishment after Implantation of a Trifocal Intraocular Lens
Published in Current Eye Research, 2021
Luis J. Escaf, Luis C. Escaf, Silvana Polo, Manuel Rodríguez-Vallejo, Joaquín Fernández
The implantation of a trifocal multifocal intraocular lens (MIOL) has been demonstrated to be a safe, predictable and effective procedure for the treatment of cataracts with the restoration, not just of the far vision, but also of the intermediate and near vision.1 Furthermore, presbyopic patients more often choose this option for achieving spectacle independence at multiple distances which has resulted in an increase of the current alternatives to cover specific patient needs.2