Foldable intraocular lenses and vitreoretinal surgery

Intraocular lens changes after short- and long-term exposure to intraocular silicone oil: An in vivo study

The aim of this study was to evaluate the interaction between various widely used intraocular lenses (IOLs) and silicone oils of different viscosities. Four groups of IOLs, including monoblock foldable hydrophilic acrylic IOLs (Morcher, type 92s); monoblock hydrophobic acrylic IOLs (Acrysof^®-SA60AT, Alcon); single-piece rigid polymethylmethacrylate (PMMA) IOLs (Intraocular Optical International-IOI-65130) and a three-piece foldable silicone optic IOL (CeeOn^® Edge 911A, Pharmacia UpJohn) were analyzed in vitro to determine the percentage adherence 1,000-centistoke, 1,300-centistoke or 5,000-centistokes silicone oil on the IOL optic. For each IOL type, there was no statistically significant difference in the mean silicone oil coverage (MSC) of the IOL optics for the different viscosities of silicone oil. Silicone IOLs had the highest MSC percentage (79.9%) whereas hydrophilic acrylic IOLs were the least silicone-covered IOLs (7.8%) compared to the other IOL types tested in this study. It is not the concentration of silicone oil that affects silicone oil coverage. When performing small-incision cataract surgery in patients who may require silicone oil injection, foldable hydrophilic acrylic or hydrophobic acrylic lenses should be preferred over standard foldable silicone lenses.

A questionnaire was sent to all members of the German Society of Ophthalmic Surgeons to evaluate complications of foldable intraocular lenses (IOLs) that required explanation. Information on preoperative visual acuity, foldable IOL design and material as well as the reason for IOL explantation was obtained and analysed. We received 167 completed questionnaires for 1998 and 1999. In 1998 and 1999 the most common reasons for IOL explantation were as follows: incorrect lens power for 56% of the 3-piece hydrophobic acrylic IOLs, 16% because of glare or other photic phenomena, 40% of the 1-piece hydrophilic acrylic IOLs were explanted because of incorrect lens power and 30% for IOL damage. For the 3-piece monofocal silicone IOLs, 41% were explanted because of incorrect IOL power and 32% because of IOL decentration. For the 1-piece Hydrogel IOL, 76% were explanted because of opacification of the optic and 14% because of incorrect lens power. Most multifocal IOLs were explanted because of photic phenomena. In addition to the most common complications such as decentration and incorrect IOL power observed in rigid IOLs, new complications associated with foldable IOLs occurred such as optic opacification, glare and photic phenomena. Some complications seemed to appear in particular IOL types (opacification: SC-60BOUV, MDR), while others were observed in all types of foldable lenses. Accurate calculation of the IOL power and further improvement of the IOL material and design seem to be necessary to minimise the rate of explantations.

Background: In Bangladesh, one-third (31%) of childhood blindness are from cataract. The management of which remains a challenge; treatment is often diffi­cult, tedious and requires a dedicated team effort. The study was done to observe the postoperative visual acuity and complication following implantation of foldable acrylic hydrophobic intraocular lens (IOL). Methods: This prospective study was done during the period of July 2006 to June 2011. This study comprised of patients in the age group of 2–16 years with unilateral and bilateral, congenital and develop­mental cataract, who underwent cataract surgery and implantation of foldable acrylic hydrophobic IOL. They were followed up at day 1, day 7, 1 month, 6 months and 1 year after operation to assess the incidence of posterior capsular opacity (PCO) and occurrence of postoperative complications. Results: Thirty-eight eyes of 30 pediatric patients underwent cataract surgery and underwent acrylic foldable IOL implantation. Postoperative anterior chamber reaction was minimum and the incidence of PCO was 18.32%. But, no severe PCO developed. Other complications like pupillary capture and decentration of IOL was also absent. Conclusions: It can be concluded that foldable acrylic hydrophobic IOL is well tolerated in the pediatric eye. There is less chance of postoperative inflammation and development of PCO. DOI: http://dx.doi.org/10.11566/cmoshmcj.v12i1.23 Chatt Maa Shi Hosp Med Coll J 2013; 12(1): 25-29

Evaluation of a 3-piece silicone intraocular lens with poly(methyl methacrylate) haptics

Uveal and capsular biocompatibility of hydrophilic acrylic, hydrophobic acrylic, and silicone intraocular lenses

目的 比较亲水性丙烯酸酯人工晶状体(intraocular leus,IOL)与硅凝胶IOL的临床效果.方法 对209例(209眼)白内障患者行超声乳化吸除联合人工晶状体植入术,A组(93眼)植入亲水性丙烯酸酯Akreos Adapt IOL,B组(116眼)植入SoFlex SE三体型硅凝胶IOL.观察两组IOL的植入性能、术中并发症、术后视力、前房反应和IOL表面色素沉着、IOL位置、后囊混浊程度.随访时间>12个月.结果 术后最佳矫正视力两组差异无统计学意义(χ =0.28,P>0.05).两组前房闪辉均较轻(+～++).IOL表面沉积物的发生率:A组3眼(占3.26%),B组13眼(占11.21%),差异有统计学意义(P 0.05).结论 与硅凝胶IOL相比,Akreos Adapt IOL植入操作更容易,并发症更少,炎症反应更低,且具有良好的居中性和稳定性,临床应用疗效满意。

Influence of surface light scattering and glistenings of intraocular lenses on visual function 15 to 20 years after surgery

Physical properties of intraocular lens (IOL) surfaces determine biocompatibility. IOL hydrophobicity of commercially available IOLs with and without fibronectin (FN) coating can be determined by surface contact angle (SCA) measurements. SCA data of IOLs may allow for a rational selection of an IOL type as a function of underlying eye disease. University Hospital of Saarland, Homburg (Saar), Germany Thirteen IOL types were tested. IOLs were made of poly(methyl methacrylate)(PMMA), acrylate, or silicone. Select IOLs were surface modified by the manufacturer with heparin or a polysaccharide coating. SCA values of IOLs, either uncoated or precoated with FN, were determined using the sessile water drop method. SCA values ranged from 61.3 to 116.1 degrees for unmodified IOLs, with PMMA IOLs being more hydrophilic (median SCA, 74.1 degrees ), silicone IOLs more hydrophobic (median SCA, 113.3 degrees ), and acrylate IOLs intermediate (median SCA, 86.6 degrees ). Upon FN coating, all genuine acrylate lenses became significantly more hydrophilic while this effect was either nonsignificant or opposite on some PMMA and silicon IOLs. Heparin or polysaccharide surface modification resulted in significantly reduced SCA values. On acrylate IOLs, SCA values did not correlate with the aqueous content of the material. This study associates IOL materials, surface modifications, and the role of FN preadsorption with SCA values reflecting surface hydrophobicity versus hydrophilicity. It provides a rationale for specific IOL selection as a function of the clinical setting, and a basis for IOL development using tailored surface physicochemistry to enhance biocompatibility and to reduce susceptibility to implant infection.

To compare the optical performance of rigid spherical polymethylmethacrylate (PMMA), foldable spherical, and foldable aspheric intraocular lenses (IOLs). Measurements were obtained monocularly from pseudophakic patients with a PMMA IOL (Ophtec PC265y or Rayner 105U), spherical AcrySof MA30 IOL (Alcon Laboratories Inc), or aspheric Tecnis ZA9003 IOL (Abbott Medical Optics). Contrast sensitivity was measured using the Holladay automated contrast sensitivity test with 5.0-mm artificial pupil at 3 and 6 cycles per degree at optimal focus and at several defocus levels. The myopic shift (shift of the optimal focus toward more myopic values at lower spatial frequencies) and depth of focus were determined. Wavefront aberrations were assessed with a Hartmann-Shack wavefront analyzer; straylight was measured using the C-Quant meter (Oculus Optikgeräte GmbH). Nine patients with a spherical rigid PMMA IOL, 19 patients with a spherical foldable IOL, and 24 patients with an aspheric foldable IOL met the inclusion criteria. Eyes with an aspheric IOL showed less spherical aberration than eyes with other IOLs; no differences were found in overall higher order aberrations. No differences in contrast sensitivity at optimal focus and in straylight were found among the IOLs. Eyes with a PMMA IOL showed a larger depth of focus compared to eyes with an aspheric IOL. Eyes with an aspheric IOL had a smaller myopic shift than eyes with other IOLs. Optical performance differences among the IOLs in this study are small, concurring with similar higher order aberrations found in the three groups. Reduction in myopic shift appears to be the most obvious effect of aspheric IOLs.

Soft intraocular lenses (IOLs) have been developed to be folded during insertion to allow implantation through a small incision. The surface of the IOL is of great importance in postoperative inflammation and long-term acceptance of the implant. Rough and sharp edges can damage delicate intraocular tissues. The purpose of this study was to analyze new, foldable silicone IOLs for surface quality prior to and following folding. Eleven silicone IOLs of different types were included in this study (four one-piece plate-haptic silicone IOLs and seven three-piece silicone IOLs with polypropylene, PMMA or polyimid haptics). We performed scanning electron microscopy on brand-new IOLs prior to and following folding either with forceps or inserter. Special attention was given to the silicone optic surface, optic edges, haptic-optic junctions and the haptic itself. Photographs were taken at 5-350 times magnification. All IOLS demonstrated a smooth and homogeneous optic surface at low magnification. At high-power magnification (X 350), distinctive surface patterns were evident in some IOLs, which turned out to be artefacts. The edge finish showed surplus silicone material and molding flash in six of 11 IOLs. Positioning holes of the 4 plate-haptic IOLs were, except in one IOL, rounded and not rough. Photographs of the haptic-optic junctions revealed surplus material or clefts between the haptic and optic in six of the 7 three-piece IOLs; the loop ends of two IOLs showed a roughened or irregular surface. We did not detect any IOL changes produced by folding. The silicone IOLs tested demonstrated generally acceptable surface properties, but most IOLs had regional surface irregularities of varying magnitude. The clinical impact of these remains to be established, but surplus material or surface defects might result in deposition of inflammatory cells, protein or microorganisms and synechia formation. Folding of the IOLs did not produce superficial defects.

To investigate the high-order aberrations (HoAs) in pseudophakia between 2 foldable acrylic intraocular lenses (IOL) with differences in the tilt of IOL. Department of Ophthalmology, Nara Medical University, Nara, Japan. Sixty-four eyes that had uncomplicated phacoemulsification and IOL implantation were assigned to 1 of 2 groups: Acryfold 60BB (HOYA [n=30 eyes]) and AcrySof MA60AC (Alcon [n=34 eyes]). All patients had best corrected visual acuity better than 20/25. High-order aberrations were measured using the Hartmann-Shack aberrometer at 4.0 mm and 6.0 mm wavefront aperture diameters, and the IOL tilt and decentration were measured using Scheimpflug videophotography. There was a significant difference in the IOL tilt (60BB=2.22 degrees +/- 1.44 (SD), 60AC=3.18 +/- 1.84 degrees; P=.041, Mann-Whitney U test), but no difference in IOL decentration (P>.05). In the cornea, there were no differences between the 2 groups in HoAs at 4.0 mm and 6.0 mm aperture diameters (P>.05, Mann-Whitney U test). In the whole eye, there was no difference between the 2 groups in spherical-like aberrations, coma-like aberrations, and total aberrations at the 4.0 mm and 6.0 mm aperture diameters (P>.05). The compensation of the internal optics with the 60BB group was better than with the 60AC group for coma-like (P=.037) and total aberrations (P=.010) at 6.0 mm aperture diameter. The smaller tilt of the IOL induced more compensation for the coma-like and total aberrations at the 6.0 mm aperture diameter. The IOL tilt should be small, especially in a large pupil, with regard to HoAs.

Posterior Capsule Opacification in Silicone and Hydrophobic Acrylic Intraocular Lenses with Sharp-edge Optics Six Years After Surgery

Having substituted the hydrophilic and hydrophobic groups alternately on the soft acrylic resin intraocular lens (IOL) surface by using an ArF excimer laser and a Xe₂ excimer lamp, we have developed the IOL that is free from fibrin. Acrylic resin or PMMA lens has been used as an intraocular lens for 50 years. However, protein and fat are stuck onto the IOL surface after a long implantation, which opacifies the surface (after-cataract). Thus, we designed the micro domain structures of hydrophilic and hydrophobic groups on the IOL surface for fibrin-free. Firstly, the IOL was irradiated with the Xe₂ excimer lamp in the presence of perfluoropolyether in order to make it hydrophobic. By this photochemical reaction, the CF3 functional groups were substituted on the IOL surface. Secondly, the ArF laser was projected on the IOL through the mask pattern in reduced size in the presence of water in order to be hydrophilic. With the photochemical reaction, the OH groups were substituted at the part exposed. The fibrin adsorption test of the modified IOL surface was carried out with FT-IR; which revealed that the fibrin-sticking rate of the treated sample has decreased by 23% compared with that of the non-treated sample. As a result, the fibrin-free IOL has been made by modifying the surface of the IOL to have the micro domain structures of the hydrophilic and hydrophobic groups that are arrayed alternately. In conclusion, the ideal intraocular lens has been demonstrated.

Significant postoperative refractive errors in vivo with the Mentor Memorylens intraocular lens