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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.
Horizontal and anterior chamber diameter for phakic intraocular lens sizing
Published in Clinical and Experimental Optometry, 2021
Adam A Oleszko, Jarosław J Marek, Maria M Muzyka‐woźniak
Phakic intraocular lens implantation for refractive error correction can be considered as an alternative procedure for keratorefractive surgery.1 The major advantage of this procedure is its reversibility. Too shallow anterior chamber depth (ACD) is a main contraindication for phakic intraocular lens implantation surgery. For posterior chamber Visian Implantable Collamer Lens (ICL), a cut‐off value 2.8-mm is suggested.2 When implantation of sulcus‐supported posterior chamber phakic intraocular lens is being planned, appropriate sizing is critical to avoid post‐operative complications, such as increased intraocular pressure, endothelial cell loss, impaired pupil function or cataract formation.3–5 Adequacy of sizing can be assessed by vault measurement (Figure 1).
Incidence and Clinical Characteristics of Post LASIK Ectasia: A Review of over 30,000 LASIK Cases
Published in Seminars in Ophthalmology, 2018
Maja Bohac, Mateja Koncarevic, Adi Pasalic, Alma Biscevic, Maja Merlak, Nikica Gabric, Sudi Patel
Retrospectively, within the ectasia cases the most prevalent risk factor was thin cornea (5 eyes/50%), anterior map irregularities (e.g., asymmetric bow tie - 4 eyes/40%), Ectasia Risk Score > 3 (4 eyes/40%), Percent tissue altered ≥ 0.4 (2 eyes/20%) and low residual stromal bed (3 eyes/30%). However, in the retrospective chart review we found 4,506 eyes (14.97%) with corneal tomography, pachymetry and PME values resembling those cases that developed ectasia (asymmetric bow tie, cornea ≤ 500µm, PME >+ 15µm). Of the 10 cases with ectasia, from the outset eight presented with myopia or myopic astigmatism and two had mixed astigmatism. The group consisted of 5 males and 2 females. Average patients age was 28.86 ± 8.38 (range 20–42). Out of 7 patients, 4 patients had unilateral ectasia. One patient had a Verisyse phakic intraocular lens implanted for myopia in his fellow eye and his cornea remained unchanged during the whole follow-up. Three other patients had LASIK surgery on both eyes. These eyes showed signs of some posterior corneal surface elevation but without increase in Kmax or deterioration of uncorrected visual acuity during the whole follow-up.
EVO/EVO+ Visian Implantable Collamer Lenses for the correction of myopia and myopia with astigmatism
Published in Expert Review of Medical Devices, 2023
Elena Martínez-Plaza, Alberto López-de la Rosa, Alberto López-Miguel, Alfredo Holgueras, Miguel J. Maldonado
While some other posterior chamber phakic intraocular lens are currently available in the market for compensating myopia and myopia with astigmatism, the outcomes of the Visian ICL have been the most assessed and the collamer material of the ICL has proven biocompatibility standing the test of time. Besides, little evidence comparing the outcomes of different phakic intraocular lens is available so far. This fact makes it challenging to determine what lens provides better outcomes for each individual case. Based on the scientific literature, ICL is the phakic intraocular lens of choice for most refractive surgeons nowadays, although comparative studies between the available phakic lenses should help to address this issue.