IOL Surface Research Articles

Прогнозирование остроты зрения на близких расстояниях для линз с увеличенной глубиной фокуса на основании данных дооперационной биометрии

Abstract Original article Prediction of near visual acuity for intraocular lens with an extended range of focus technology based on preoperative biometry data E.V. Danilenko, A.N. Kulikov, N.V. Nevin S.M. Kirov Medical Militar y Academy Ministr y of Defense of the Russian Federation, Saint-Petersburg, Russian Federation Purpose. To develop a method for predicting near visual acuity at 40 cm after TECNIS Symphony IOL implantation based on preoperative biometry data. Material and methods. 2 groups of patients were enrolled in the study – the test group (50 eyes), where IOL TECNIS ZCB00 was implanted, and the main group (30 eyes), who received the TECNIS Symphony lens. Preoperatively all patients underwent Lenstar LS900 measurement and OCT of the anterior segment Cassia 2. There were no differences in biometry and demographic parameters between the groups. In the postoperative period, the measurements were repeated, refraction, distance and near visual acuity were also determined in the main group. The follow-up period was 6,48±0,15 months. Results. The posterior surface of the TECNIS IOL was 0.06±0.17 mm (p=0.022) closer to the cornea than the center of the crystalline lens. Center of the crystalline lens depth had correlation with the distance between cornea and the anterior (R=0.76 and R=0.74 according to Cassia 2 and Lenstar, respectively, p=0.000 in both cases) and posterior IOL surface (R=0.74 and R=0.86, p=0.000 in both cases). The average near visual acuity in the main group was 0.50±0.20 and did not depend on the axial length of the eye, IOL power, length of the vitreous chamber, residual ametropia and gender. Based on the results of regression analysis, an equation was derived for predicting near visual acuity after implantation of the TECNIS Symphony IOL (sum of squares 0.83, p=0.000), which included center of the crystalline lens depth, flat cornea meridian power and its thickness. Conclusion. Near visual acuity at 40 cm after implantation of TECNIS Symphony IOL can be reliably predicted based on center of the crystalline lens depth, flat cornea meridian power and its thickness. It is also possible to use the simplified nomogram proposed by the authors. Key words: EDOF, near vision acuity prediction, presbyopia

Simulation of the effect of capsular opacification on retinal illumination

Posterior capsular opacification is the most common complication after cataract surgery with intraocular lens implantation. Different strategies have been proposed to avoid PCO including 360° continuous sharp edges of the posterior IOL optics rim, haptics angulations, or surface modification of the optics. However, depending on the IOL material and surgical technique 20 to 60% of eyes require Nd:YAG laser capsulotomy in the first 2 years after cataract surgery. In this talk we would like to define a scattering model for the posterior lens capsule and perform raytracing through the pseudophakic eye with a scattering capsule to investigate the impact of biometric parameters on the scatter characteristics and contrast transfer of the eye.

Studying the Interaction of Viteral Substitutes with the Surface of Acrylic Intraocular Lenses

Purpose of the study: In vitro to study the degree of adhesion of vitreous substitutes, such as silicone oil of various viscosities and perfluorodecalin (PFOS), to hydrophobic acrylic polymer IOLs and evaluate the interaction of vitreous substitutes with the model MIOL-Soft-23 in the clinic. Material and methods. IOLs of the model MIOL-Soft-23 were taken for the experiment. MIOL-Soft-23 are included in the RPR-20 set. IOL of the model MIOL-Soft-23 is made by photopolymerization from a biocompatible spatially cross-linked hydrophobic acrylic polymer based on oligomers and monomers of the methacrylic series with filters in the ultraviolet region of the spectrum from 19 to 23 D. For the experiment, silicone oils of different viscosities were taken: RS-OIL 2000 (Alchimia), SIL-5000-S (DORC), Oxane 5700 (Bausch & Lomb), PFOS (perfluorodecalin) Dk-line (Bausch & Lomb). Also, saline sodium chloride 0.9 % (Solofarm) was used. Results. Revealed a decrease in the degree of silicone adhesion to the surface of acrylic hydrophobic IOLs as the temperature rises, not less than 1.5 %. The absence of dependence of the degree of adhesion on the degree of viscosity of silicone oil was confirmed, which corresponds to the literature data. For the first time, the average percentage of adhesion of perfluorodecalin to the IOL surface data were obtained, in particular, the MIOL-Soft-23 model. The range of values ranged from 0.7 to 7.2 %. The average coverage percentage is 1.9 ± 1.3 % (exposure at 37 ± 1 °C for up to 14 days) and 3.4 ± 1.5 % (exposure at room temperature for up to 14 days). This confirms the need for careful intraoperative monitoring of the completeness of removal of PFOS droplets from the IOL surface. Conclusion. The presence of the risk of adhesion of residual drops of silicone oil and PFOS to the surface of the IOL necessitates careful intraoperative control of the completeness of the removal of vitreous body substitutes, as well as further search for the best ways to eliminate this complication. The conducted complex of studies makes it possible to recommend the use of IOL model MIOL-Soft-23 in complicated cases of vitreal surgery.

Микроскопический анализ помутнений гидрофильных ИОЛ

In the structure of surgical interventions currently performed on the organ of vision and its adnexa, cataract phacoemulsification occupies the first place. However, there are frequent cases of Iol explantation in the late postoperative period due to their opacification. Purpose is to study the surface of cloudy Iols by means of electron microscopy and to determine the elemental composition of the identified deposits. Material and methods. microscopy of the surface of 8 explanted hydrophilic Iols was carried out using a digital inverted microscope «altami InVErt 3» with a magnification from 40x to 800x times. Elemental analysis of surface deposits was carried out on a Jeol Jcm-6000 electron microscope (Japan) with a JEd- 2300 energy dispersive analysis attachment. Results. It has been established that the morphological structure of the deposits on the Iol is represented by various crystals, in some places forming a continuous film that does not penetrate into the Iol material. the elemental composition of deposits has the following structure: carbon (c) — 40 %, nitrogen (n) — 18 %, oxygen (o) — 40 %; potassium (K), magnesium (mg), Sodium (na), phosphorus (p) — 2 % (all elements in total). Conclusion. Opacification of the hydrophilic type Iol has a membranous structure, presented in the form of deposits on the surface of the entire Iol, and not just in the pupillary lumen. considering the molecular composition of the deposits, it should be assumed that they are of an organic nature. Keywords: IOL explantation, cataract phacoemulsification, IOL opacities

Post operative opacification of polymethylmethacrylate, hydrophilic and hydrophobic acrylic intraocular lenses: A retrospective observational study

: To evaluate post-operative opacification of hydrophobic, hydrophilic and polymethylmethacrylate intraocular lenses. We had performed a retrospective observational study on twenty-one patients in tertiary care hospital of North India and a private clinic from March 2020-January 2021. History of systemic diseases like diabetes mellitus, hypertension, gout, chronic obstructive pulmonary disease was noted. We had also evaluated the patients for ophthalmic conditions like recurrent uveitis, retinal surgery, paracentesis for hyphema, open globe injury repair. The diagnosis of intraocular lens opacification was made on careful slit lamp examination. The patients with severe loss of visual acuity had undergone intraocular lens exchange procedure. The explanted intraocular lenses were sent for light microscopy with special stain and scanning electron microscopy. Statistical analysis was performed using SPSS software, version 21 (SPSS, Inc.) We found that mean age of patients with intraocular lens opacification was 62.5±6.82 years. The occurrence was 16(76.19%) in hydrophilic IOL, 4(19.05%) in hydrophobic IOL and only one (4.76%) was PMMA IOL which showed that the occurrence if IOL opacification is more in hydrophilic IOL. Light microscopy and scanning electron microscopy of the explanted IOLs did not show any deposits over IOL surface. Special stains were used and it was noted that Alizarin red was positive while Von Kossa for calcium was negative. We concluded that intraocular lens opacification can occur in any type of intraocular lens, but is predominantly seen with hydrophilic acrylic intraocular lenses. Also we came to a conclusion that various ophthalmic pathologies and systemic comorbidities accelerated the process of opacification.

Spectral-Domain OCT Lens Meridian Position as a Metric to Estimate Postoperative Anatomical Lens Position.

To evaluate the prediction of postoperative anatomical lens position (ALP) using intraoperative spectral-domain optical coherence tomography (SD-OCT) lens anatomy metrics in patients who underwent femtosecond laser-assisted cataract surgery. Intraoperative SD-OCT (Catalys; Johnson & Johnson Vision) and postoperative optical biometry (IOLMaster 700; Carl Zeiss Meditec AG) were used to assess anterior segment landmarks, including lens thickness, lens volume, anterior chamber depth, lens meridian position (LMP), and measured ALP. LMP was defined as the distance from the corneal epithelium to the lens equator, and ALP was defined as the distance from the corneal epithelium to the IOL surface. Eyes were divided into groups according to axial length (> 22.5 mm, 22.5 to 24.5 mm, and > 24.5 mm) and IOL type (Tecnis ZCB00 [Johnson & Johnson Vision]; AcrySof SN-60WF [Alcon Laboratories, Inc], or enVista MX60E [Bausch & Lomb]) to further analyze the correlation between LMP and ALP. Theoretical effective lens position was back-calculated using a specific formula. Primary outcome was correlation between postoperative measured ALP and LMP. A total of 97 eyes were included in this study. Linear regression analysis displayed a statistically significant correlation between intraoperative LMP and postoperative ALP (R2 = 0.522; P < .01). No statistically significant correlation was observed between LMP and lens thickness (R2 = 0.039; P = .06) or between ALP and lens thickness (R2 = 0.02; P = .992). The greatest predictor for ALP was LMP (β = 0.766, P < .001; R2 = 0.523). Intraoperative SD-OCT-measured LMP correlated better than anterior chamber depth and axial length to postoperative ALP. Further studies are necessary to analyze the impact of preoperative or intraoperative LMP measurements on postoperative refractive outcomes. [J Refract Surg. 2023;39(3):165-170.].

Comparative stability of intraocular lenses during 2–20 years of artificial aging, potential effects in terms of biocompatibility

AbstractIntraocular lenses (IOLs) are worldwide used for cataract surgery. Mostly made of acrylate polymers, they can lead to an unexpected biocompatibility reaction such as posterior capsular opacification (PCO). Acrylate polymers suffer from both oxidative and heat/thermal aging that affect their properties. We examined the stability of four currently available acrylic IOLs, three hydrophobic and one amphiphilic, under artificial aging that simulate intraocular conditions from 2 to 20 years. Released degradation products were detected by reversed‐phase high performance liquid chromatography. Thermal properties were investigated using thermogravimetric analysis, and differential scanning calorimetry measurements. Surface topography was analyzed by atomic force microscopy. The effect on biocompatibility was estimated with protein sorption of the aged lenses. Both surface and thermal properties changed under aging. Surface roughness of implants increased under aging in a kinetic in two steps. The aging also changed the polymer structure. These changes lead to a variable release of degradation products according to the chemical design of the copolymer. Glass temperature transition (Tg) and thermal degradation stability also suffered from aging. The aging has led to significant changes in protein sorption affinity to IOL surfaces. For pure hydrophobic acrylic copolymer, stability was higher for copolymers containing at least one fluoro methacrylate. The amphiphilic polymer appeared to have a time‐dependent aging that can affect the implant flexibility and could impact late biocompatibility reaction and tolerance.

Role of fibronectin and IOL surface modification in IOL: Lens capsule interactions

Posterior Capsule Opacification (PCO) is one of the most common complications of cataract surgery. While studies have shown that IOL material properties and fibronectin adsorption may affect IOL-induced PCO in the clinical setting, the mechanism governing such interactions is not totally understood. Since strong adhesion forces between IOLs and posterior capsules (PCs) have been shown to impede cell infiltration and thus reduce PCO formation, this study was designed to assess whether fibronectin adsorption and IOL material properties would impact the IOL:PC adhesion force and cell infiltration using a PCO predictive in vitro model and a macromolecular dye imaging model, respectively. Our results showed that fibronectin adsorption significantly increased the adhesion forces and reduced simulated cell infiltration between acrylic foldable IOLs and the PC at physiological temperature in comparison to fibronectin-free controls. This fibronectin-mediated strong IOL: PC bond may be contributing to low PCO rates in the clinic for acrylic foldable IOLs. In addition, acrylic foldable IOLs coated with Di(ethylene glycol) (Diglyme), a hydrophilic coating known to reduce protein adsorption, was tested for its ability to alter adhesion force and cell infiltration. We observed that IOLs coated with Diglyme coating greatly reduced surface hydrophobicity and fibronectin adsorption of acrylic foldable IOLs. Furthermore, Diglyme coated IOLs showed significantly reduced adhesion force and increased simulated cell infiltration at the IOL:PC interface. The overall results support the hypothesis that IOL surface properties and their ability to adsorb fibronectin may have great impact on the IOL:PC adhesion force. A tight binding between IOLs and PC may contribute to the reduction of cell infiltration and thus the PCO incidence rate in the clinic.

Clinical Study of Intraocular Lens Implantation by Scleral Suture Fixation after Lensectomy and Vitrectomy

Objective: To investigate the surgical techniques and clinical significance of intraocular lens implantation by scleral suture fixation after lensectomy and vitrectomy. Methods: According to the inclusion and exclusion criteria, 19 cases (20 eyes) were selected for IOL implantation by scleral suture fixation after lensectomy and vitrectomy. The uncorrected visual acuity (VA), best-corrected visual acuity (BCVA), intraocular pressure (IOP), preoperative IOL position and surface clarity, and complications were recorded, analyzed and compared. Results: In 20 eyes of 19 patients who underwent IOL implantation by scleral suture fixation in this study, both VA and BCVA after surgeries were significantly improved compared with those before surgeries (P&lt;0.05). 11 eyes of 10 patients had IOP ≥ 21mmHg before surgeries. Three months after surgeries, IOP of all these affected eyes were within 21 mmHg, and no affected eyes required the application of ocular hypotensive drugs. Three months after surgeries, 17 eyes of 16 patients (85%) had centered IOL position and 3 eyes of 3 patients (15%) had slightly tilted IOL, all of these tilted IOLs were in patients with ocular trauma and all of them were found to be caused by scar adhesion in the peripheral part. In two eyes, the IOL optical edge was completely blocked by the pupil, which was only found after dilating the pupil. The pupil of one eye was traumatic and irregularly dilated, and the edge of the optical part of IOL was exposed. In two eyes of two patients who underwent silicone oil removal and IOL fixation during the same surgery, a small number of silicone oil droplets were found on the surface of IOL in the early stage after surgeries, and in the later stage, small flakes of pigment granules were observed. During the 3-month postoperative follow-up period, no patient had complications such as IOL dislocation, exposure of fixation suture, retinal detachment and corneal endothelial decompensation. Conclusion: For patients ....

Analysis and comparison of monofocal, extended depth of focus and trifocal intraocular lens profiles

To test the feasibility of using profilometers to extract information about IOL surfaces design. A standard monofocal IOL (Tecnis 1), a monofocal IOL that provided some depth of focus (Eyhance), an extended depth of focus IOL based on refractive optics (Mini Well) and a trifocal IOL based on diffractive optics were used in this study (Tecnis Synergy). The surface topography of the IOLs was measured by using a multimode optical profilometer. Posterior surface of Tecnis 1 IOL was spherical and the anterior surface aspherical. In the Eyhance IOL, posterior surface was spherical and anterior surface did not fit to any of our reference surfaces, indicating a higher order aspheric surface design. In the Mini Well Ready IOL, a best-fit sphere surface was obtained for the second surface and a high order aspherical surface design was deduced for the first surface. The anterior surface of the Synergy IOL was aspherical and the base curve of the diffractive structure fitted very well to a spherical surface. To consider an aspheric surface as possible best-fit surface provided more information than if only best-fit spherical surface was considered. The high order aspheric surface designs employed in the IOLs studied presented differences, regarding best-fit asphere surface, higher than 1 micron. These differences were correlated with the generation of spherical aberration complex profiles (with Zernike terms higher than 4th order) and with the production of distinct amounts of depth of focus. This method was also useful to deduce the base curve of diffractive surfaces.

Photo-responsive intraocular lens with on demand drug release for posterior capsule opacification prevention and improved biosafety

Posterior capsular opacification (PCO) is the most common complication after cataract surgery, which is caused by the adhesion, proliferation, migration and epithelial-mesenchymal transformation of the residual lens epithelial cells (LECs) in lens capsule. The drug eluting coating modification provides a powerful way to inhibit PCO incidence after IOL implantation. However, the uncontrolled proliferative drug brings intraocular biosafety issues when application. Therefore, developing new strategies with controlled drug release for PCO prevention is of great significance. In this investigation, a hydrophilic photo-responsive drug release coating was successfully constructed on IOL surface, which was verified through 1H•NMR, UV–Vis, FTIR and XPS. In vitro assay indicated that the IOL coating exhibited excellent anti-adhesion and anti-proliferation effects on LECs under irradiation. The photo-controlled drug release in vitro can be achieved by simply adjusting the intensity and time of irradiation. Finally, the surface-modified IOL was implanted in rabbit eyes and in vivo evaluation was carried out. In vivo assay demonstrated that the implantation of the modified IOL into eyes can significantly reduce the occurrence of PCO. Moreover, the modified IOL exhibited good biocompatibility and biosafety. We believe that this work will provide a synergistic strategy for effective prevention of PCO through a photo-controllable drug release coating on IOL surface.

Лечение последствий длительной тампонады силиконовым маслом при рецидивирующей отслойке сетчатки у пациента с ретинопатией недоношенных

Objective. To present the clinical and functional results of combined treatment of the complications of long-term silicone oil tamponade in a patient with retinopathy of premature. Materials and methods. A 24-year-old patient diagnosed with stage 4b retinopathy of premature in a single seeing right eye. Between 2011 and 2020 underwent 5 microinvasive revisions of the vitreous cavity with replacement of silicone oil and median duration of silicone oil tamponade of 19+25.5 months over this entire period. Because of the constant migration of emulsified silicone oil to anterior chamber due to weakness of iridolenticular ligaments, band keratopathy developed in the right eye, opacity of the IOL due to the adhesion of precipitates on its anterior and posterior surfaces, pupillary membrane, and aggravation of the proliferative membrane on the ocular surface. UCVA was proectio incerta and IOP was 17 mmHg. The median thickness of the cornea was 853 μm, the average thickness of the corneal calcifications is 57 μm. The patient underwent revision of the vitreous cavity with removal of the pupillary membrane, the next steps were to install bandage sutures in the anterior chamber parallel to iris in two mutually perpendicular surfaces to create additional barriers to silicone oil migration. Then we used 27 mg of K3-EDTA to produce 0.1% chelating solution and to remove corneal calcium deposits. Final stage was YAG – laser discision of precipitates from the IOL surfaces. Results. Postoperatively UCVA of the right eye in 1-month was 0.05, IOP was 17 mmHg and endothelial cell density was 1200 cells / mm2. According to OCT data the median corneal thickness was 640 μm, the thickness of the epithelial layer was 39 μm. Biomicroscopically, cornea was transparent, a single silicone oil vesicle in the lower segment of anterior chamver, the bandage sutures are consistent, the IOL is centered with a transparent optical zone, silicone oil visualized on the fundus, epi- and subretinal proliferates were delimited by laser coagulates, epiretinal membrane was in the macular region. Key words: retinopathy of prematurity, silicone oil, emulsification, ribbon-like keratopathy, bandage threads, EDTA.

Results of Scanning Electron Microscopy of Explanted Hydrophilic Acrylic IOLs

Purpose: study the microscopic examination and microtopography of explanted hydrophilic acrylic IOLs with opacification.Material and methods. 5 samples of soft hydrophilic acrylic IOLs produced in European countries and the USA were studied. Explanted IOLs were studied using a scanning electron microscope (EVO LS10, Karl Zeiss, Germany-UK).Results. In 4 cases changes in hydrophilic acrylic IOL had the character of surface opacification in the area of the anterior wall of the optical element of the lens with localization in the Central zone (pupil area). In one case, the opacities were located over the entire surface of a hydrophilic IOL having a hydrophobic coating. The changes were characterized by the formation of crystalline deposits on the IOL surface at different stages of evolution. In the initial stage, primary point precipitates with sizes of 3–5 microns were formed. At a later stage, the changes had the form of “adult” spherocrystals with a typical radial-concentric zonal structure, up to 50 microns in size. In one of the of IOLs, the growth of crystals under the surface of the lens — in the thickness of IOLs was determined.Conclusion. The changes characterize different stages of the same type of pathological process with sedimentation of crystal deposits on the surface of IOL with changing crystallomorphology.

Surface modification of intraocular lenses via photodynamic coating for safe and effective PCO prevention.

Posterior capsular opacification (PCO) is an emerging complication in cataract phacoemulsification and intraocular lens (IOL) implantation surgery, mainly stemming from the adhesion, proliferation, and trans-differentiation of the post-surgery residual lens epithelial cells (LECs). Previous investigations have shown that an anti-proliferative drug eluting coating on the IOL surface provides an effective way to inhibit PCO. However, due to the undesirable elution of the anti-proliferative drug, the safety of such modification is one of the important issues to be solved. In this investigation, photodynamic coating was introduced into IOL surface modification. The photosensitizer chlorin e6 grafted α-cyclodextrin (α-CD-Ce6) was synthesized and self-assembled onto the poly(poly(ethylene glycol) methacrylate) (PPEGMA) brush established IOL surface via the supramolecular interaction between α-CD and poly(ethylene glycol) chains. The results of investigation into its optical properties, including transmittance, refractive index, and surface morphology, showed no obvious alterations after photodynamic coating modification on the IOL surface. The in vitro LEC behaviour investigation optimized the photodynamic therapy parameters when light illumination was used for the cell elimination on the photodynamic coating modified IOL. The results have also shown that this functional coating modification effectively eliminates the cells on the surface of the IOL material when treated with light illumination, whereas it keeps excellent cytocompatibility in the absence of light illumination. The investigation of the cell elimination mechanism shows that this kind of functional coating eliminates the adherent cells by ROS induced apoptosis. The in vivo implantation result confirms the excellent PCO inhibition effect, as well as their safety and biocompatibility to the surrounding tissues. As a result, the proposed photodynamic coating provides a safer and effective alternative of IOL modification for preventing PCO.

A Modified Femtosecond Laser Technique for Anterior Capsule Contraction Syndrome.

Anterior capsule contraction syndrome (ACCS) is a rare, late complication of cataract surgery, associated with impairment of visual function. In this paper, we describe a new surgical technique to treat ACCS by femtosecond laser procedure. The femtosecond laser was used to perform an anterior capsulotomy with a customized size, in order to avoid IOL damage. After ophthalmic viscosurgical device injection in the anterior chamber, the anterior capsule flap was separated from the IOL surface by gentle hydrodissection. This manoeuvre enabled an easy and safe removal of the fibrotic material by vitreal microscissors. Our technique allowed a complete removal of the fibrotic material and opening of the capsule, with immediate complete visual acuity recovery without IOL damage. In conclusion, femtosecond laser appears to be safe and effective for treatment of ACCS with long-lasting efficacy.

Оптимизация фемтосекундной лазерной транссекции гидрофобной интраокулярной линзы и отдаленные результаты в клиническом исследовании (первый опыт)

Purpose. To optimize the energy parameters of the FL assistance using the LenSx FL unit for transection of IOL made of hydrophobic material, as well as to develop a sparing surgical technique for the IOL removal from the anterior chamber. Material and methods. In the experimental part of the study, the femtosecond laser transection of IOL was carried out using the LenSx unit in different energies (1, 2, 4, 6, 8, 10µJ). The subsequent mechanical separation of IOL was evaluated according to a 4-point scale. Single IOL fragments after transection (n=3) were studied under experimental conditions using the optical light microscopy in 40 and X100 magnifications The preexplantation FL transection was performed under clinical conditions in one patient. The Evaluation of FL transsection of IOL was carried out using the electron microscope with magnification x47 and х800. Results. Under experimental conditions, the pulse energy levels (2, 4, 6, 8, 10 µJ) showed the similar efficiency of IOL transection. The level of energy 1µJ – manual separation of the IOL along the line of transection was impossible. High energy loads (8, 10µJ) entailed a change in the surface of IOL of unknown nature. In clinical conditions the technique of FL transection of IOL showed its safety and efficiency. Conclusion. Hydrophobic IOLs can be fragmented using the femtosecond laser.

Pigment dispersion syndrome and pigmentary glaucoma after secondary sulcus transscleral fixation of single-piece foldable posterior chamber intraocular lenses in Chinese aphakic patients

To describe secondary pigment dispersion syndrome (PDS) and pigmentary glaucoma after secondary sulcus transscleral fixation of 1-piece hydrophobic acrylic foldable posterior chamber intraocular lenses (PC IOLs) in aphakic patients in a Chinese population. Department of Ophthalmology, Qingdao Municipal Hospital, Qingdao, China. Retrospective case series. This chart review included eyes that had secondary sulcus transscleral fixation of a 1-piece hydrophobic acrylic foldable PC IOL (Tecnis ZCB00) between March 2011 and March 2014. The patients' demographic data, clinical data, postoperative complications, intervals between initial surgery and the onset of PDS, pigmentary glaucoma occurrences, and findings on slitlamp biomicroscopy, gonioscopy, and ultrasound biomicroscopy (UBM) were recorded. The study comprised 23 consecutive eyes of 21 patients. Seventeen eyes of 16 patients were diagnosed with PDS, and 7 eyes of 6 patients were diagnosed with pigmentary glaucoma. The slitlamp examination and UBM showed that the location between the IOL optic and the posterior surface of the iris was very close. Slitlamp examination of the anterior chamber angle using a gonioscope showed dense pigment deposition on the IOL surfaces. A reverse pupillary block was found in 10 eyes of 9 patients. Other postoperative complications included intraocular hemorrhage, pupillary capture of the IOL optic, IOL tilt, IOL decentration, IOL dislocation, and suture erosion. The 1-piece hydrophobic acrylic foldable PC IOL was not suitable for sulcus transscleral fixation because of a high incidence of PDS and pigmentary glaucoma after surgery in a Chinese population.

A clinical observation on the implantation of domestically made foldable intraocular lens in diabetic cataract patients

Objective To observe the safety and effect of implanting domestically made hydrophobic acrylic foldable IOL(DF-IOL) for the patients with diabetic cataract. Methods One hundred and twenty five eyes of 82 cases of diabetic cataract were operated with phacoemulsification and DF-IOL implantation.The visual acuity, corneal edema, anterior chamber inflammation, intraocular pressure (IOP) and posterior capsule opacification (PCO) after the surgery were observed. Results The pupillary dilation was not ideal in 9 eyes and the posterior capsular rupture(PCR) with a tiny hole when polishing occurred in 1 eye. The DF-IOL was implanted into the capsular bag in all cases without intraoperative hyphema or zonular dialysis. One day after the suegery, the visual acuity was less than 0.3 in 10 eyes(8.00%), better than 0.3 in 115 eyes (92.00%), better than 0.5 in 89 eyes (71.20%) and better than 0.8 in 23 eyes (18.40%). Thirty-four eyes(27.20%) had corneal edema which faded away within 1 week. No keratic precipitate, intraocular hypertension, synechia, IOL surface exudate or endophthalmitis occurred.The incidence rate of PCO was only 8.80%. Conclusion DF-IOL implantation is safe and effective for diabetic cataract. Key words: Lens, intraocular, foldable, domestically made; Cataract; Diabetes, type-Ⅱ

Postoperative membranous proliferation outgrowth onto the anterior surface of hydrophobic acrylic intraocular lenses

Purpose: The aim of this study was to determine the correlation factors and features of membranous outgrowth onto the anterior surface of hydrophobic acrylic intraocular lenses. Methods: This study included 145 eyes from 135 consecutive patients who had cataract surgery with implantation of a single-piece, foldable, hydrophobic acrylic intraocular lens. Postoperatively, the IOL optic was examined by slit-lamp microscopy at 1 week and1 month to determine the incidence, extent, and correlation factors of membranous proliferation. If MP was present, we re-examined the patient monthly to monitor the condition. The extent of this proliferation was assessed using a clock-face representation of the IOL optic as the number of hours in which membranous proliferation could be identified. Results: Twenty-four eyes were excluded from analysis and 121 remaining eyes were studied. Membranous proliferation was documented in 46 (38.02%) of the pseudophakic eyes. Furthermore, the incidence of membranous outgrowth was greater in pseudophakic eyes characterized by older age, shorter axial length and more serious anterior segment vitreous opacity. Membranous proliferation was greater in the inferior (35.11%) and nasal quadrants (33.51%) than in the superior and temporal quadrants (where the incisions were made). The total area of membranous proliferation was slightly less than one quadrant (56.52%). Conclusions: Shorter axial length, older age, serious anterior segment vitreous opacity, and the inferior and nasal quadrants are risk factors for membranous proliferation on the IOL surface. Appreciation of these risk factors may lead to establishing procedures that will lessen anterior capsule opacification and capsule contraction syndrome simultaneously.

Multifocal intraocular lens providing optimized through-focus performance

A widespread type of multifocal intraocular lens (MIOL) is based on expanding the depth of focus with specific amounts of spherical aberration. However, knowing the optimal wavefront aberration for multifocality does not directly provide a MIOL geometry. To overcome this issue, we present a new strategy to design MIOLs. The method optimizes directly the IOL surface geometries (aspheres with aspherical coefficients up to tenth order) using a multisurface pseudophakic eye model and a multiconfiguration approach, where the merit function jointly considers the optical quality at different object plane locations. An example of MIOL [22 diopters (D) far distance correction] was designed. For this design, the ocular modulator transfer function (MTF) at 50 cycles per millimeter remained above 0.47 for all object locations. The design provides high optical quality performance for far and intermediate distances and peak optical performance at near distances (MTF>0.57). Additionally, the design shows good performance against pupil changes (3-5 mm pupil diameter range). Finally, when the MIOL was tested on pseudophakic eye models with corneal spherical aberrations within a typical population range, the high multifocal performance was maintained in almost 40% of potential patients (ignoring asymmetric aberrations effects).