This paper reviews recent studies of the role of the tear film in the optical quality of the eye. Recent investigations focus on the dynamics of the tear film after a blink and its important role in the optical quality of the eye. The results in this review were used in an attempt to understand the optical and visual impact of tear-film breakup in normal eyes and dry eyes. It was noted that patients with dry-eye syndrome have large optical aberrations compared with those in normal eyes, which may be the cause of blurry vision associated with the syndrome. In addition, instillation of artificial tears reduces optical aberrations and thus improves the optical quality of vision in these patients.

We aimed to summarize the outcomes reported following the implantation of the V4c implantable collamer lens with a central port (ICL, STAAR Surgical Inc) for myopia correction. A literature search in PubMed, Web of Science and Scopus was carried out to identify publications reporting clinical outcomes of patients who were implanted with the V4c ICL model and had a follow‐up period of at least 6 months. A total of 35 clinical studies published between 2012 and 2020 were included in the present review. A comprehensive analysis of the available data was performed, focusing on visual and refractive outcomes at different time‐points post‐surgery. In addition, adverse events and other parameters such as endothelial cell density, intraocular pressure and vault measurements—which were evaluated in some of the studies—were also compared. This review encompassed a total of 2904 eyes. The outcomes reported in this review lead us to conclude that ICL V4c implantation for myopia correction is a safe and efficient procedure, with stable visual and refractive outcomes and low adverse event rates. The patient’s anterior segment should be thoroughly characterized, and the ICL parameters should be carefully selected so as to achieve good outcomes and avoid complications.

We reviewed recently published studies that analyzed the visual and optical quality in eyes with different spherical and aspheric intraocular lenses (IOLs). Recent studies focused on visual quality metrics, such as visual acuity and contrast sensitivity, under photopic and mesopic lighting conditions and optical metrics, such as wavefront aberrations, especially spherical aberration. The results in this review were used in an attempt to understand whether there is a visual and/or optical benefit of implanting aspheric IOLs over implanting spherical IOLs.

This study aimed to summarize the outcomes reported when swept-source optical coherence tomography (SS-OCT) is used for ocular biometry. A literature search was performed to identify publications reporting clinical outcomes of patients measured with commercial SS-OCT. Twenty-nine studies were included in this review. A comprehensive analysis of the available data was performed, focusing on parameters used for intraocular lens (IOL) power calculation in cataract surgery, including keratometry, central corneal thickness, white-to-white distance, anterior chamber depth, lens thickness, axial length, IOL power, and pupil diameter. Different metrics for repeatability, reproducibility, and agreement between devices were analyzed. In general, SS-OCT biometers provide excellent repeatability and reproducibility outcomes; however, the differences obtained for some parameters measured in agreement studies should be carefully analyzed to validate the interchangeability between devices. The good outcomes reported lead us to conclude that optical biometers based on SS-OCT technology are likely to become the gold standard for ocular biometry.

To evaluate the optical quality of Acrysof Restor SN6AD1 refractive-diffractive +3.00 D and Lentis Mplus LS-312 nonrotational symmetric +3.00 D aspheric multifocal intraocular lenses (IOLs) and analyze the effect of tilt and decentration. University of Valencia, Valencia, and University of Murcia, Murcia, Spain. Experimental study. An artificial model eye was used to measure wavefront aberrations of both IOL models. The modulation transfer function (MTF) and point-spread function (PSF) were calculated for a 5.0 mm pupil and under 5 situations: centered, 0.2 mm and 0.4 mm decentered, and 2 degrees and 4 degrees tilted. The refractive-diffractive IOL had the highest MTF values at all spatial frequencies. Similarly, the PSF was worse for the refractive-diffractive IOL. The MTFs for the refractive-diffractive IOL decreased when the IOL was decentered or tilted, being more robust for tilting than decentration. The MTFs for the nonrotational symmetric IOL were similar under all testing conditions. Cutoff frequencies for the refractive-diffractive IOL were stable over the range of tilting studied and comparable with the cutoff when the IOL was centered (approximately 50 cycles per degree [cpd]). When the IOL was decentered, the cutoff frequency decreased by approximately 40 cpd. The nonrotational symmetric IOL cutoff frequencies for misalignment and tilt were low (approximately 30 cpd) and similar under all conditions. The refractive-diffractive IOL provided better optical quality than the nonrotational symmetric IOL. Tilt and decentration had a significant impact on optical quality with both IOLs, being more severe with the nonrotational symmetric IOL.