Influence Of Intraocular Lens Research Articles

Imaging Function and Relative Light Transmission of Explanted Opacified Hydrophilic Acrylic Intraocular Lenses.

We evaluated the influence of intraocular lens (IOL) opacification on the optical performance of explanted hydrophilic acrylic IOLs. We performed a laboratory analysis of 32 Lentis LS-502-1 (Oculentis GmbH, Berlin, Germany) IOLs, explanted due to opacification, in comparison with six clear unused samples of the same IOL model. Using an optical bench setup, we obtained modulation transfer function (MTF), Strehl ratio, two-dimensional MTF, and United States Air Force (USAF) chart images. In addition, we assessed light transmission through the IOLs. The MTF values of opacified IOLs at 3-mm aperture were similar to those of clear lenses, with the median (interquartile range) values of 0.74 (0.01) vs. 0.76 (0.03) at the spatial frequency of 50 line pairs per millimeter in clear and opacified IOLs, respectively. The Strehl ratio of opacified lenses was not lower than that of clear lenses. The USAF-chart analysis showed a considerable reduction in brightness in opacified IOLs. The median (interquartile range) relative light transmission of opacified IOLs in comparison to clear lenses was 55.6% (20.8%) at the aperture size of 3 mm. In conclusion, the explanted opacified IOLs had comparable MTF values to those of clear lenses but significantly reduced light transmission.

Influence of IOL Weight on Long-Term IOL Stability in Highly Myopic Eyes.

PurposeThis study aimed to investigate the influence of intraocular lens (IOL) weight on long-term IOL stability in highly myopic eyes.Materials and MethodsA total of 205 highly myopic cataract eyes of 205 patients implanted with the MC X11 ASP (Group A, 86 eyes) or 920H IOL (Group B, 119 eyes) were included in this retrospective study. Eyes were divided into 3 subgroups according to the IOL power: low (≥-5 to <5 D), medium (≥5 to <14 D), and high (≥14 D) IOL power. At 3 years after surgery, IOL decentration and tilt, high-order aberrations, and anterior capsular opening (ACO) area were measured. The influence of IOL weight on long-term IOL stability was evaluated.ResultsGroup B had a significantly greater IOL weight than Group A (Group B vs. Group A: 28.31 ± 2.01 mg vs. 25.71 ± 4.62 mg, P < 0.001). Correspondingly, Group B presented significantly greater overall and inferior decentration than Group A, especially for low and medium IOL power (all P < 0.05). In both groups, overall and vertical decentration was significantly correlated with IOL weight (all P < 0.05). Group B showed a significantly greater ACO area than Group A (P < 0.05). Multivariate analysis showed that decentration in Group A was affected by IOL weight, while decentration in Group B was affected by IOL weight and AL.ConclusionsHigher IOL weight may lead to greater long-term IOL decentration in highly myopic eyes, while the haptic design may play a role in anterior capsular contraction.

The Influence of Intraocular Lenses (IOLs) on the Properties of Filters Protecting Human Eyes against Optical Radiation in the Work Environment.

Under the specific illumination conditions of many workplaces, e.g., in the metallurgical industry, decreased lighting may impair workers’ vision and, as a result, their productivity. Spectrophotometric tests of two types of protective optical filters (welding filters and infrared protection filters), two types of intraocular lenses (IOLs with and without yellow chromophore), and filter-IOL systems were carried out. In spectrophotometric studies, the spectral characteristics of transmission and the coefficients for the assessment of light transmission were determined. This study explores the relationship between the eye protection levels offered by filters and the use of intraocular lenses (IOLs), and especially those containing a yellow chromophore which may lower the luminous transmittance of protective filters. In our previous works, we studied a large number of optical protective filters and many factors influencing their performance. A review of the literature has shown the absence of prior research on the subject. For this purpose, transmittance reduction factors were defined for the evaluation of the filter-IOL system. The spectral characteristics of luminous transmittance for the tested IOLs indicate a significant decrease of transmittance for those with yellow chromophore within the range up to approx. 475 nm, as compared to IOLs without chromophore. The main objective of this study was to determine whether people with IOLs need different protective filters against harmful optical radiation as well as whether IOLs may change the required category of protective filters. The key finding is that while the use of IOLs in conjunction with protective filters does change the light transmission coefficient, it does not affect the filter protection levels. The transmittance reduction factors were similar (0.95 to 0.99 relative units) for all filter-IOL systems irrespective of the presence or absence of yellow chromophore. It must be said clearly that, in reference to the requirements specified in the standards, IOLs did not affect the filter protection levels. This means that the quality of vision did not change significantly when using the analyzed filters and IOLs.

Impact of intraocular lens characteristics on intraocular lens dislocation after cataract surgery

BackgroundTo assess the influence of intraocular lens (IOL) characteristics on IOL dislocations after cataract surgery.MethodsPatients who underwent cataract surgery at the Department of Ophthalmology Graz, Austria, between 1996 and 2017...

Posterior Capsule Opacification and Nd-YAG rates evaluation in a large series of pseudophakic cases

To evaluate the influence of Intraocular Lens (IOL) material and design on Posterior Capsule Opacification (PCO) and Neodymium-YAG (Nd-YAG) rates in eyes implanted with different Posterior Chamber Intraocular Lenses (PC IOLs) designs at the end of uncomplicated cataract surgeries. Oculus Eye Clinic, Bucharest, Romania. Retrospective, observational study. This study comprised 4805 eyes operated for cataract in 2012 and 2013 with a post-operative average follow up of 40 ± 6,15 months (27-54 months). The PCO and Nd-YAG rates were recorded and compared among different IOL materials and designs and among different pathology groups. From 4805 IOLs implanted, 2560 (53,27%) were hydrophilic and 2245 (45,73%) hydrophobic, 2937 (61%) were aspherical and 1868 (39%) spherical. We found statistical significant differences in the PCO and Nd-YAG rates between hydrophilic (18% and 14% respectively) and hydrophobic lenses (4% and 2% respectively) (p<0.0001). There were also statistically significant differences in the sub-group of hydrophilic aspheric IOLs, finding lower PCO and Nd:YAG rates with the C-loop haptics configuration (12,6% and 3,3% respectively) compared with the broad optic/ haptic junction (29,75% and 24,73% respectively) (p<0.001). No statistically significant differences on PCO and Nd:YAG rates were found for the different associated pathologies (p>0.05). Hydrophilic lenses showed statistically higher PCO and Nd:YAG rates than hydrophobic lenses. In contrast, the optic asphericity and the associated pathologies had no influence on the PCO and Nd:YAG rates. IOL design and material seem to be the main characteristics influencing PCO and Nd-YAG rates. LECs = lens epithelial cells.

Influence of intraocular lens tilt and decentration on wavefront aberrations

Purpose: To investigate the influence of intraocular lens (IOL) tilt and decentration on higher-order aberrations (HOAs) using wavefront analysis. Setting: Department of Ophthalmology, Nara Medical University, Nara, Japan. Methods: Forty eyes of 40 patients with a 5.5 mm optic, foldable acrylic IOL were examined 4 to 48 months postoperatively. Ocular wavefront aberrations of the central 4.0 mm aperture diameter were measured using a Hartmann-Shack aberrometer. Higher-order aberrations from the 3rd to 4th order were calculated using Zernike polynomials. The relationship between IOL tilt and decentration, measured with a Scheimpflug camera, and ocular HOAs were investigated. Results: The correlation between IOL tilt and coma-like aberrations was significant ( r = 0.431, Spearman rank correlation coefficient; P = .007). However, the correlation between IOL tilt and the spherical-like and total aberrations was not significant ( P>.05), nor was the correlation between IOL decentration and coma-like, spherical-like, and total aberrations ( P>.05). Conclusions: Intraocular lens tilt influenced ocular coma-like aberrations. The quality of the retinal image may improve by reducing IOL tilt.

Effect of intraocular lens optic edge design and material on fibrotic capsule opacification and capsulorhexis contraction

To examine the influence of intraocular lens (IOL) optic edge design and optic material on fibrosis of the anterior and peripheral posterior capsules and on capsulorhexis contraction. Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. This randomized controlled patient- and examiner-masked study comprised 210 eyes of 105 patients with bilateral age-related cataract. In Group 1 (n = 53), the Sensar OptiEdge AR40e hydrophobic acrylic IOL with a sharp posterior optic edge was compared with the AR40 acrylic IOL with a round edge. In Group 2 (n = 52), the ClariFlex OptiEdge silicone IOL with a sharp posterior optic edge was compared with the PhacoFlex SI-40 silicone IOL with a round edge All IOLs were manufactured by Advanced Medical Optics, Inc. Standardized digital slitlamp images of anterior capsule opacification (ACO) and fibrotic posterior capsule opacification (PCO) were taken 1 year postoperatively, and digital retroillumination images were taken at 1 week and 1 year. The intensity of fibrotic PCO was graded subjectively (score 0 to 4), ACO was graded objectively (score 0% to 100%), and the capsulorhexis area (mm(2)) was determined objectively. One year after surgery, the mean ACO score was 32% in eyes with the sharp-edged acrylic IOL and 29% in eyes with the round-edged acrylic IOL (P<.05). In the silicone group, the mean was 31% and 26%, respectively (P<.05). The mean fibrotic PCO score was lower in eyes with a sharp-edged acrylic IOL than in eyes with a round-edged acrylic IOL (0.26 and 0.93, respectively; P<.05) and in eyes with a sharp-edged silicone IOL than in eyes with a round-edged silicone IOL (0.24 and 0.82, respectively; P<.001). At 1 year, the mean capsulorhexis area was statistically significantly smaller in eyes with a sharp-edged silicone IOL than in eyes with a round-edged silicone IOL (P<.05). Acrylic and silicone IOLs with the sharp OptiEdge design led to significantly less fibrotic PCO but more ACO than round-edged acrylic and silicone IOLs. The sharp-edged silicone IOL caused significantly more capsulorhexis contraction than the round-edged silicone IOL and both acrylic IOLs.

Lens epithelial cell reaction after implantation of different intraocular lens materials: Two-year results of a randomized prospective trial

Purpose To determine the influence of intraocular lens (IOL) material on anterior capsular opacification and membrane growth over the anterior IOL surface in patients who have undergone standardized small-incision cataract surgery and foldable IOL implantation in the capsular bag. Design Randomized controlled trial. Participants Eighty-eight cataract patients (88 eyes). Methods Patients were randomly assigned to receive one of four different foldable IOLs after phacoemulsification: Storz Hydroview H60M, Corneal ACR6D, AMO SI40NB, and Alcon AcrySof MA60BM. Examinations on days 7, 30, 90, 180, 360, and 720 after surgery included ophthalmologic examination, slit-lamp biomicroscopy, and photography using red reflex and focal illumination of the anterior IOL surface. Main outcome measures Best-corrected visual acuity was measured at each examination. In addition, the anterior capsule opacification and the membrane growth on the anterior IOL surface were graded according to a subjective method by the same researcher. Results The fibrosis of the anterior capsule was more frequently observed in the group using Corneal ACR6D and AMO SI40NB. The Hydroview and ACR6D groups showed a higher percentage of cases with membrane growth from the rhexis edge on the anterior IOL surface. AcrySof showed the lowest presence of fibrosis of the anterior capsule, and no membrane growth was noted. Conclusions Anterior capsule opacification is an index of IOL biocompatibility. The natural location of lens epithelial cells (LECs) precludes the possibility of the IOL's design influencing the anterior capsule behavior. The local response of LECs varies according to the IOL studied. This may be related to the chemical and physical properties of the materials used in the different IOLs.

Influence of intraocular lens material and design on postoperative intracapsular cellular reactivity

To evaluate the influence of intraocular lens (IOL) material and design on the outcome of postoperative lens epithelial cell proliferation within the capsular bag after cataract surgery.A total of 5,079 human globes containing rigid and foldable posterior chamber IOL styles commonly implanted in the United States (n = 8) were analyzed in this study. Each globe, fixated in 10% formalin, was sectioned at the equator and analyzed using the Miyake-Apple posterior technique. The study consisted of 3 parts: First, to evaluate posterior capsule opacification (PCO); the Nd:YAG laser posterior capsulotomy rate (%) was documented and plotted on a monthly basis, creating a computerized trend line for each IOL style. Second, to evaluate anterior capsule opacification (ACO); 460 globes were processed for histologic examination. Anterior capsule fibrosis was scored from 0 to III, according to the thickness of proliferative tissue/cells on the inner surface of the anterior capsule at the capsulorhexis margin. Third, interlenticular opacification (ILO) was studied by analysis of 3 pairs of acrylic piggyback lenses that had been explanted because of opacification between their optics. Each IOL pair was processed for histologic examination, and scanning electron microscopy was performed on 1 of the lenses.In the first study, relatively higher Nd:YAG laser posterior capsulotomy rates (19.1% to 32.8%) were noted with the 4 oldest IOL designs in this study (2 foldable lenses, 1 3-piece polymethyl methacrylate [PMMA] design, and 1 single-piece all-PMMA design). Four modern lenses, 1 acrylic lens, and 3 silicone foldable IOL designs had Nd:YAG rates ranging from 1.3% to 14.6% (P < .0001). In the second study, mean ACO scores were highest with silicone-plate lenses (1.77 +/- 0.86 and 1.28 +/- 0.77). The lowest mean score was observed with the acrylic lens (0.51 +/- 0.52; P < .0001). In study 3, the analyses of the 3 pairs of explanted acrylic piggyback lenses showed that the opacification between them (ILO) may have different forms.Control of postoperative intracapsular cellular proliferation is important in avoiding 3 significant clinical complications. Postoperative lens epithelial cell proliferation is involved in the pathogenesis of PCO, ACO, and ILO, the latter being a newly described form of opacification within the capsular bag related to piggyback IOL implantation. IOL material and design are important factors influencing the outcome of these complications.

Preoperative assessment of intraocular lens corrected vision

At present, preoperative estimation of the influence of intra-ocular lenses (IOL) on visual performance, that is not only based on visual acuity but on the whole contrast sensitivity function (CSF), is only possible with high efforts. We describe a method to evaluate the CSF of a patient after IOL implantation. The method is based on the knowledge of a normal subject's CSF, and the modulation transfer function of the IOL that can be measured or computed. Comparison of computed and measured CSF with monofocal and multifocal IOL shows that the method allows prediction of visual performance after implantation of the IOL.

The triple procedure: in the bag placement versus ciliary sulcus placement of the intraocular lens

AIMSTo evaluate the influence of intraocular lens (IOL) placement on triple procedure clinical results and to investigate whether it is appropriate to use phacoemulsification in patients with large lens nucleus.METHODS40...

Lens epithelial cell regression on the posterior capsule with different intraocular lens materials

BACKGROUND/AIMSPosterior capsular opacification (PCO) is caused by proliferation and migration of lens epithelial cells (LECs) across the posterior capsule and is the commonest cause of reduced vision after cataract surgery....

Influence of intraocular lenses on ultrasound axial length measurement: In vitro and in vivo studies

Refraction affects ultrasound as it passes obliquely through tissues or materials with different propagation speeds. Therefore, axial length measurements could theoretically be affected after implantation of an intraocular lens which has a propagation speed that exceeds those of the ocular humors by a factor of 1.8 (2718 m·s−1 vs. 1532 m·s−1).The in vitro studies we report clearly demonstrate that ultrasound axial length measurements were not affected significantly by inclining the IOL up to 25° or varying the transducer-lens distance from 0 to 25 mm. However, length measurements were found to be directly proportional to the lens power. A 27-diopter lens induced a 0.032-mm increase in the apparent axial length for a lens-reflector plate distance of 20mm (P < 0.05).In vivo the retina's curvature counterbalances this apparent increase: axial lengths measured in 26 patients were virtually the same after IOL implantation.From these data we conclude that axial lengths can be accurately measured by ultrasound after IOL implantation if the different propagation speeds are considered for calculation.