Poly Methyl Methacrylate Intraocular Lens Research Articles

Management of traumatic dislocated polymethyl methacrylate intraocular lens following globe rupture in a monocular patient: A case report

A 72-year-old monocular male with no light perception in the left eye and a history of cataract extraction with polymethyl methacrylate (PMMA) intraocular lens (IOL) implantation and retinal detachment repair with scleral buckling in the right eye presented after a forward fall and hitting his face with a large iris defect, irregular pupil, superior zone 2 globe rupture, dense vitreous hemorrhage, and a 1-piece PMMA IOL dislocated in the posterior chamber in the right eye. His visual acuity on presentation was hand motion with directionality, with no improvement on pinhole. PMMA IOLs are difficult to cut and require larger incisions for removal, which was difficult in our patient with open-globe rupture. His large iris defect and minimal capsular support ruled out other options such as the implantation of a new IOL. IOL repositioning with scleral suturing resulted in the successful salvation of his IOL and visual acuity.

Modified Four-Point Scleral Fixated Sutured Posterior Chamber Intraocular Lens Implantation Using 2 Eyelets Polymethyl Methacrylate Lens and 8-0 Polypropylene Suture.

To present a modified technique of 4-point scleral fixation using polymethyl methacrylate (PMMA) 2 eyelets intraocular lens (IOL) with 8-0 polypropylene sutures. A 270-degree conjunctival peritomy is done, and 4 sclerotomies (2 nasal and 2 temporal) are created. Lamellar scleral or clear corneal incision is made at superior site (6 mm wide for sclera or 5.5-6 mm for corneal). A short segment of 8-0 polypropylene is inserted into each eyelet, each thread of the suture is externalized through the sclerotomy site, and the lens is inserted. The suture is tightened evenly, and the knot is rotated and internalized. Scleral incision and conjunctival peritomy are sutured with 8-0 vicryl. We have performed this technique in 6 patients with excellent visual outcomes and no reported complications over 1 year of follow-up. This technique has practical advantages including rigid and stable PMMA IOL, high tensile, and slim 8-0 polypropylene suture which is easily internalized and less irritated, and affordable and widely available overall consumables. We present a modified 4-point scleral fixation technique for posterior chamber IOL placement using PMMA IOL with 2 eyelets and 8-0 polypropylene as compared to previous studies that used foldable IOL with 4 eyelets and 10-0 polypropylene or Gore-Tex sutures. This procedure has moderate technical complexity, comparable to previously reported techniques with good overall clinical outcomes and several practical advantages, particularly related to the affordability and availability of the consumables.

Scleral fixation of a novel modified, injected canine intraocular lens by haptic capture, in 17 dogs.

The aims of lens removal surgery are to re-establish or preserve both a clear visual axis and emmetropic vision. Trans-scleral intraocular lens (IOL) fixation has been described in cases where lens capsule instability precludes the insertion of a prosthetic intraocular lens into the lens capsule. Previous techniques have necessitated enlargement of the corneal incision to accommodate either a rigid polymethylmethacrylate IOL or an acrylic foldable IOL inserted using forceps. This paper reports the modification of an endocapsular IOL to be used as an injectable suture-fixated IOL introduced through a 2.8 mm corneal incision. All cases underwent lens extraction by phacoemulsification followed by removal of the unstable lens capsule. A PFI X4 IOL (Medicontur) was modified to create four open-loop haptics. The IOL was injected into the anterior chamber, each haptic was captured in a loop of suture introduced ab externo, and the lens was sutured with four-point fixation. The results from 20 eyes in 17 dogs are reported. Over an average follow-up time of 14.5 months, vision was retained in 16/20 eyes. Vision was lost in four eyes due to corneal ulceration and ocular hypertension (1/20), retinal detachment (2/20), and Progressive Retinal Atrophy (1/20). The modified PFI X4 proved suitable for injection and scleral fixation through a 2.8 mm corneal incision, with a success rate comparable to previously published techniques.

Flanged Sutureless Intrascleral Fixation of Dislocated Hard 1-Piece Polymethyl Methacrylate Intraocular Lenses.

To describe the vitreoretinal surgical technique and report the outcomes of our method of sutureless flanged intrascleral haptic fixation of dislocated 1-piece polymethyl methacrylate intraocular lenses with rigid haptics. Ciliary sulcus-based scleral tunnels were created by placing valved 27-gauge (g) trocar cannulas limbus parallel with conjunctival displacement. After complete vitrectomy, the rigid haptics were then externalized using 27g forceps. Cautery was then used to form flanges at the haptic tips. The haptics were then pushed back into the mouths of the scleral tunnels. Flanged intrascleral fixation was successfully achieved in eight eyes of seven patients. The average age at the time of surgery was 75 ± 13.7 years, with a mean follow-up of 17.9 ± 16.3 months (range 3-42 months). Intraocular lens dislocation/subluxation was the most common indication for surgery. All patients fully recovered to their potential acuity by their third postoperative visit. The most significant complication was erosion of one haptic in one patient, which was successfully managed without requiring intraocular lens exchange. There were no complications of subsequent dislocation, endophthalmitis, retinal detachment, or uveitis-glaucoma-hyphema syndrome. Flanged sutureless intrascleral fixation of dislocated 1-piece polymethyl methacrylate intraocular lenses with rigid haptics can be safely and successfully performed, avoiding the large wound creation accompanying intraocular lens exchange and the disadvantages of suture-based techniques.

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.

Evaluation of Nd:YAG laser capsulotomy results in patients who underwent cataract extraction and intraocular lens implantation with the endocapsular phacoemulsification method

Background/Aim: Posterior capsular opacification (PCO) is a common complication that develops after cataract surgery, and it can be treated neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy. In this study, we aimed to investigate the effects of different intraocular lenses (IOLs) on the development of posterior capsule opacification (PCO), to determine the time between surgery and Nd:YAG laser capsulotomy, and to evaluate the efficacy, effectiveness, and complications of capsulotomy in patients who underwent cataract surgery with the phacoemulsification method and subsequently developed PCO. Methods: The cohort study included one eye of each of 153 cases (63 males, 90 females) who underwent cataract surgery with the phacoemulsification method in our clinic from August 1, 2006, through August 1, 2008, and subsequently developed PCO. According to the type of IOL implanted, the cases were divided into three groups: polymethylmethacrylate IOL (Group 1), hydrophilic acrylic IOL (Group 2), and hydrophobic acrylic IOL (Group 3). The control examinations of the patients who underwent Nd:YAG laser capsulotomy were undertaken before capsulotomy and at the first week, first month, and third month after capsulotomy. Results: Visual acuity improvement was detected in 96.7% of the 153 cases. It was determined that 9.1% of the cases had an intraocular pressure (IOP) increase of more than 5 mmHg at the third hour after capsulotomy and approached baseline values at the end of 1 week. The mean total energy used in all the cases was 37.20 (14.70) mjl. The mean total energy used in 14 patients with an IOP elevation of above 5 mmHg was 71.07 (10.59) mjl. Nd:YAG laser capsulotomy was performed at an average of 6.29 (4.91) months in Group 1, 7.81 (4.35) months in Group 2, and 17.7 (12.35) months in Group 3. After capsulotomy, clinically significant cystoid macular edema was observed in 1.9% of the cases, IOL damage in 3.9%, and vitreous hemorrhage in 0.6%. Conclusion: In this study, the incidence of PCO development was found to be lower in the patients who underwent hydrophobic acrylic IOL implantation; therefore, this type of lens should be preferred for implantation. Although Nd:YAG laser capsulotomy is an outpatient treatment method that can be applied quickly and can increase visual acuity, it can also lead to complications. To eliminate most of these complications, it would be beneficial to minimize the energy used during the laser procedure.

Snowflake degeneration of polymethyl methacrylate intraocular lens material

Snowflake degeneration of polymethyl methacrylate intraocular lens material

Posterior continuous curvilinear capsulorhexis with anterior vitrectomy vs optic capture buttonholing without anterior vitrectomy in pediatric cataract surgery.

To investigate long-term complications after pediatric cataract surgery with implantation of a heparin-coated polymethyl methacrylate intraocular lens (PMMA IOL) and posterior continuous curvilinear capsulorhexis (PCCC) with anterior vitrectomy vs PCCC without anterior vitrectomy with optic capture buttonholing. Department of Ophthalmology, Goethe University, Frankfurt, Germany. Prospective randomized clinical trial. Eyes with unilateral or bilateral congenital cataract without further pathologies or former surgeries were randomly assigned in 2 groups: cataract removal, IOL implantation, and PCCC with anterior vitrectomy (group A) or posterior optic buttonholing without anterior vitrectomy (group B). The main outcome measures were posterior capsule opacification (PCO), complication rates, and refractive development. 58 eyes of 41 pediatric cataract surgery patients were included. The mean age at the time of operation was 66.05 months (±29.39). In group A (n = 26), 2 eyes required treatment for PCO, whereas the optic axis remained clear in all eyes in group B (n = 30), which was statistically insignificant. In addition, group B had a slightly lower rate of complications. The mean spherical equivalent after a mean postoperative follow-up of 6.5 years was -0.11 ± 2.51 diopters (D) (-5.0 to +4.0 D) in group A and -0.08 ± 2.14 D (-5.0 to +4.0 D) in group B, which was also statistically insignificant. Optic capture with a heparin-coated PMMA IOL proved to be a safe technique in the prevention of secondary cataract formation without a higher rate of complications and the necessity of vitrectomy.

Cataract Surgery Results after Penetrating Keratoplasty

Objective. To compare clinical and refractive outcomes of cataract surgery by phacoemulsification and by extracapsular cataract extraction with implantation of foldable and rigid intraocular lenses in patients previously having undergone penetrating keratoplasty (PK).Patients and methods. This is a retrospective study. Medical records of all patients admitted for cataract surgery between 2010 and 2018 to the King Abdullah University Hospital (KAUH) were reviewed and medical records of patients who underwent cataract surgery after PK were analyzed. Medical records of 95 patients (58 males and 37 females; average age 40.0 ± 19.9 years) were selected. Depending upon the type of surgical technique applied, the cases were divided into two groups: first group included 60 patients who underwent cataract surgery by phacoemulsification with implantation of different foldable intraocular lenses (IOL), the second group included 35 patients who underwent cataract surgery by extracapsular cataract extraction (ECCE) with implantation of a polymethylmethacrylate (PMMA) IOL. The choice of ECCE technique with implantation of rigid IOLs was made if the endothelial cell density after PK was less than 2200 cells/mm2 and cataracts were of 4 and 5 grades to exclude additional trauma to the endothelium by ultrasound energy. Demographic and clinical data were collected. The R statistical program and SPSS were used for data analysis. The P value < 0.05 was considered statistically significant.Results. Analysis showed that PK was performed mainly due to 4 indications: keratoconus (KC) — 77 % cases, herpetic keratopathy — 7 % cases, Eye trauma — 5 % cases, previous graft rejection — 5 % cases and Stevens–Johnson syndrome — 1 % cases. The mean best corrected visual acuity (BCVA) in the first group improved from 0.40 ± 0.05 to 0.80 ± 0.05 postoperatively. The mean BCVA in the second group improved from 0.30 ± 0.05 to 0.70 ± 0.05. In the late postoperative period BCVA with foldable IOLs was higher by 0.10 ± 0.05, as compared with the results obtained with the rigid IOLs. Mean intraocular pressure (IOP) changed from 15.1 ± 4.9 before PK to 16.3 ± 5.3 after PK.Conclusion. KC was the most common indication for PK in Jordan. Results of our analysis showed that cataract surgery could be successfully performed in eyes after PK with favorable results and improvement in patients’ quality of life. Cataract surgery by phacoemulsification with implantation of foldable IOLs results in higher (BCVA) compared to ECCE with implantation of PMMA IOLs. Unless contraindicated otherwise, phacoemulsification technique with foldable IOL implantation should be given preference over ECCE with implantation of rigid PMMA IOLs in visual rehabilitation of cataract patients after PK.

Inferior Removal of Dislocated Polymethyl Methacrylate Intraocular Lens and Scleral Refixation in Glaucomatous Eyes.

IntroductionThe aim of this study was to report a technique for the removal of dislocated polymethyl methacrylate (PMMA) intraocular lenses (IOLs) in glaucomatous eyes.MethodsDislocated PMMA IOLs were removed from the inferior sclerocorneal incision, and sutureless intrascleral fixation of each IOL was performed to preserve the intact superior conjunctiva and sclera for future trabeculectomy or to maintain a functional filtering bleb of trabeculectomy. ResultsIn two cases, the condition of the bleb did not change, while the intraocular pressure improved or did not change after the procedures. IOL fixation was stable with no complications, such as tilt, decentration, or extrication of the IOL haptics.ConclusionThis procedure of preserving the superior conjunctiva and sclera can maintain the function of the bleb, superior cornea and sclera and may contribute to the success of future trabeculectomy.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40123-022-00477-z.

Commentary: Decision-making in the management of surgical aphakia.

According to the 2015–2019 survey by the National Programme for Control of Blindness and Visual Impairment, uncorrected aphakia accounts for 1.7% of blindness and vision impairment in adults aged >50 years in India.[1] Anisometropia, aniseikonia, prismatic distortion of images (jack-in-the-box phenomenon) and the weight of high hyperopic spectacles demands rehabilitation in surgical aphakia with an intraocular lens (IOL) implantation. IOLs provide a better field of vision and less image disparity, and are more acceptable cosmetically. The standard of care of in-the-bag implantation of an IOL, may not be feasible in circumstances where there is a lack of posterior capsular support. Such instances are not uncommon in a regular cataract surgeon’s practice. Further recourse depends on the presence or absence of sulcus support. While, in the presence of an adequate sulcus support, a foldable 3-piece or a rigid polymethyl methacrylate (PMMA) IOL is preferred, in its absence, the choice of IOL fixation depends on the surgeon’s expertise. We congratulate the authors for summarizing the desired options for aphakia management by the anterior and posterior segment surgeons, in their study “Preferred practice patterns in Aphakia management in adults in India - A Survey”.[2] Although this study elaborates on the preferred site of IOL fixation being the iris and scleral-fixated IOLs by anterior and posterior segment surgeons, respectively, the results cannot be extrapolated to a larger population, considering the minimal response rate (4.8%). The primary indication for secondary IOL, age of the patient at surgery, associated ocular and systemic conditions, level of training of surgeons, and the availability of different types of IOLs should also be considered when such a survey is being conducted. Optical correction is a critical component of visual rehabilitation in aphakia. There are pros and cons to each of the modalities of IOL fixation. Owing to the higher risk of hyphema, secondary glaucoma and corneal endothelium decompensation, either scleral-fixated or iris-fixated IOLs are being preferred over the use of angle-fixated anterior chamber IOLs nowadays.[3] The decision to use iris-fixated or scleral-fixated IOLs depends on the expertise of the surgeon.[45] The visual outcome in both types of IOL fixation are comparable at variable follow-up periods, although long-term prospective studies are required to confirm the same.[5678] Each of these methods have inherent complications associated with them. Iris-fixated IOLs, either anteriorly or posteriorly, are associated with iris erosion, pigment dispersion, corectopia, hyphema, IOL subluxation, cystoid macular edema, chronic uveitis and secondary glaucoma.[58] In addition to the aforementioned complications, scleral-fixated IOLs, either sutured or suture-less, are associated with vitreous hemorrhage, haptic exposure, retinal detachment, scleral thinning and IOL tilting and/or dislocation.[59] As opposed to the in-the-bag IOL and angle-fixated anterior chamber IOL (ACIOL), the procedure for iris-fixated and scleral-fixated IOLs is technically challenging, has a steep learning curve and needs expertise. The long-term stability of the these IOLs as well as complications are yet to be studied prospectively. Nevertheless, these results cannot be extrapolated to the pediatric aphakic population. Age, size of the eyeball, corneal diameter, primary indication of aphakia, eye growth, systemic associations, and high prediction errors are factors to be considered while planning IOL implantation in children. Primary IOL implantation is usually discouraged in children with small eyes (short axial length/microcornea) and those with associated anterior and posterior segment pathologies. When children reach the appropriate age, and their eyes are of the adequate size with open angles on gonioscopy and have no contraindications, a secondary three-piece IOL or a PMMA IOL in-the-sulcus/in-the-bag can be planned.[10] When sulcus examination becomes difficult clinically, ultrasound biomicroscopy of the anterior segment can be done. This provides the surgeon with information on the status of ciliary sulcus and its surrounding tissue preoperatively.[10] The vigilance on the postoperative course in children should be high as they are at a risk of excessive postoperative inflammation and rise in intraocular pressure. In specific cases such as ectopia lentis caused by Marfan syndrome, it is preferrable to leave the children aphakic and rehabilitate them with contact lenses or spectacles. Thus, for a customized approach to manage a case of aphakia, weighing the risks and benefits of the procedure is encouraged. Various factors to be considered are age, indications, contraindications, site of IOL fixation, IOL POWER calculation formula, IOL material/designs and expertise in the procedure. The historic Latin phrase, Primum non nocere, meaning, “First, do no harm,” should be respected, and selected cases should be left aphakic and rehabilitated with contact lenses or spectacles, rather than implant an IOL and cause irreversible damage due to glaucoma, corneal decompensation and retinal detachment.

Delayed complete opacification of intraocular lens

A 70-year-old male farmer underwent cataract surgery by the phacoemulsification technique 6 years ago. The patient has experienced diminished vision for the last 6 months. Slit-lamp biomicroscopy demonstrated significant opacification of the optic and haptic portion of the intraocular lens (IOL). The IOL was explanted followed by implantation of a polymethyl methacrylate IOL. The vision improved to 20/30 postoperatively. No IOL opacification was observed at follow-up visits. Histopathological evaluation of the explanted IOL exhibited calcium deposits in the optic and haptic portions of the IOL. We propose a new IOL opacification classification on the basis of etiology.

Cases of intraocular lens opacification in pseudophakic eyes: analysis of the results of microstructural studies

Relevance. Currently, all over the world, during cataract surgeries, a huge number of intraocular lenses (IOLs) made of different materials are implanted. Alongside with the development of modern IOL materials and designs, publications about their opacities appear. The nature and the localization of IOL opacities mainly depend on the properties of the material out of which the lens is made. Polymethyl methacrylate (PMMA) currently rarely used to manufacture IOLs, tends to cloud in the optical center due to structural breakdown, forming snowflake-like cracks. Opacities of acrylic IOLs depend on the degree of hydrophilic properties of the material. The deposition of crystalline deposits in the optical zone of hydrophilic acrylic lenses leads to a significant decrease in visual acuity and requires IOL explantation. There is a definite dependence of the occurrence of opacities in hydrophilic acryl on the patients concomitant diseases. In hydrophobic acrylic IOLs, vacuoles form, and glistenings occurs. Herewith, visual functions, as a rule, do not suffer.
 Purpose: to find out what structural changes in the IOL led to the need to remove them from pseudophakic eyes due to a decrease in visual acuity.
 Materials and methods. Four clouded IOLs made from different materials were examined. The lenses were studied using a SUPRA 55VP scanning electron microscope (Carl Zeiss, Germany) using a secondary electron detector. Element distribution maps on the surface and inside the lenses were collected using an X-max 80 mm2 energy dispersive X-ray analysis detector (Oxford Instruments, UK).
 Results. A hydrophilic lens with hydrophobic coating became cloudy 5 years after implantation. Hydroxyapatite crystals were found on all parts of the IOL along its surface. In a hydrophobic acrylic IOL, microvacuoles and cavities in the optical center were found using scanning electron microscopy. Two PMMA IOLs underwent self-destruction within 8 years after implantation. Chemical analysis of PMMA lenses did not reveal any inorganic compounds.
 Conclusion. One of the complications of IOL implantation is an impairment of their transparency. Factors associated with IOL material and manufacturing, as well as the patients comorbidities, can lead to lens opacification at various terms after surgery.

An in vitro system to investigate IOL: Lens capsule interaction

Posterior capsule opacification (PCO) is the most common complication associated with intraocular lens (IOL) implantation. Unfortunately, current in vitro models cannot be used to assess the potential of PCO due to their failure to simulate the posterior curvature of the lens capsule (LC) and IOL, a factor known to affect PCO pathogenesis in clinic. To overcome such a challenge, a new system to study IOL: LC interaction and potentially predict PCO was developed in this effort. It is believed that the interactions between an IOL and the lens capsule may influence the extent of PCO formation. Specifically, strong adhesion force between an IOL and the LC may impede lens epithelial cell migration and proliferation and thus reduce PCO formation. To assess the adhesion force between an IOL and LC, a new in vitro model was established with simulated LC and a custom-designed micro-force tester. A method to fabricate simulated LCs was developed by imprinting IOLs onto molten gelatin to create simulated three dimensional (3D) LCs with curvature resembling the bag-like structure that collapses on the IOL post implantation. By pushing the LC mold vertically downward, while measuring the change in position of the bending bar with respect to its start position, the adhesion force between the IOLs and LCs was measured.An in vitro system that can measure the adhesion force reproducibly between an IOL and LC with a resolution of ~1 μN was established in this study. During system optimization, the 10% high molecular weight gelatin produced the best LC with the highest IOL: LC adhesion force with all test lenses that were fabricated from acrylic foldable, polymethylmethacrylate (PMMA) and silicone materials. Test IOLs exerted different adhesion force with the 3D simulated LCs in the following sequence: acrylic foldable IOL > silicone IOL > PMMA IOL. These results are in good agreement with the clinical observations associated with PCO performance of IOLs made of the same materials. This novel in vitro system can provide valuable insight on the IOL: LC interplay and its relationship to clinical PCO outcomes.

Sutured Scleral Fixation of Posterior Chamber Intraocular Lens in Children under the Age of 9 with Congenital Ectopia Lentis

Introduction: This study aimed to report the visual acuity outcomes and complications of sutured scleral fixation of posterior chamber intraocular lens (IOL) in children under 9 years old with congenital ectopia lentis. Methods: Twenty-six children (47 eyes) with congenital ectopia lentis were included in this study. The mean age at surgery was 61.6 ± 22.3 months (range, 32–94). Patients underwent lens extraction, anterior vitrectomy, and sutured scleral fixation of posterior chamber IOL. The implanted IOL included rigid polymethyl methacrylate (PMMA) IOL (CZ70BD, n = 36) and foldable IOL (SA60AT, n = 9, and LI61SE, n = 2). The outcome measures used to assess the benefits were uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refraction, intraocular pressure, and any associated complications. Median follow-up was 33.0 months (range, 4–129). Results: After surgery, the median UCVA (1.30 vs. 0.35 logMAR) and BCVA (0.82 vs. 0.15 logMAR) improved significantly (p < 0.001). The median absolute spherical values decreased considerably (9.00 vs. 0.75 D; p < 0.001). The median astigmatism was lower in foldable IOL compared to rigid PMMA IOL (1.0 vs. 2.5 D; p = 0.026), but neither the UCVA nor BCVA was significantly different. There was no intraoperative complication. Postoperative complications included pupillary capture in 4 eyes (9%), IOL decentration in 4 eyes (9%), choroid edema in 1 eye (2%), and subretinal hemorrhage in 1 eye (2%). The rate of secondary surgery was 9%, caused by IOL decentration of IOL haptics which was broken in 3 eyes and suture degradation in 1 eye. Conclusion: Sutured scleral fixation of posterior chamber IOL provided good visual outcomes in children under 9 years of age with congenital ectopia lentis. Although there were some risks of secondary surgery, the complications were acceptable.

A transparent hydrophilic anti-biofouling coating for intraocular lens materials prepared by "bridging" of the intermediate adhesive layer.

The attachment of bio-foulants, including unwanted cells, proteins, and bacteria, to a medical device such as an intraocular lens can lead to implantation failure. Hydrophilic polymers are often used as surface modifiers in the fabrication of anti-biofouling coatings, but a hydrophilic coating can easily become swollen and peel off the substrate. In this study, we chose polymethyl methacrylate (PMMA) as the representative material of intraocular lenses because PMMA has better biocompatibility, a higher refractive index, better optical clarity, lighter weight, more stable performance, and lower cost than other intraocular lens materials. We fabricated polyvinyl alcohol (PVA) coatings with or without a "bridge", that is, an intermediate adhesive layer (AL), to increase the adhesion bonding effect between the anti-biofouling coating and the substrate. The results indicated that the prepared coatings were transparent and noncytotoxic. Moreover, the anti-adhesion properties of the cells and the resistance properties to nonspecific protein adsorption of PMMA modified by both AL and PVA coatings were better and more durable compared with the sample only modified with a physically dipped PVA coating. The coating prepared by AL "bridging" provides a new strategy for the preparation of a transparent hydrophilic anti-biofouling coating suitable for PMMA intraocular lens materials.

Catarata morganiana bilateral em paciente com aniridia congênita - relato de caso

A diminuição da visão devido à importante opacidade de meios é comum em aniridia, porém existem poucos relatos de cirurgia combinada nesta condição. A cirurgia de catarata com implante de lente intra-ocular de polimetilmetacrilato continua sendo um desafio para os cirurgiões, devido ao maior peso desse material e à diálise zonular apresentada por esses pacientes. O presente estudo, tem como objetivo relatar um caso de aniridia em uma paciente jovem, apresentando catarata hipermadura.

Microscopic Characteristics of Late Intraocular Lens Opacifications

The increases in overall life expectancy and in lens surgeries performed on younger patients have resulted in a significant increase in the anticipated duration of artificial intraocular lenses (IOLs) in the eye. Thus, the physicochemical properties of the IOL become a critical issue, and several types of postoperative IOL opacifications have been reported. To describe the microscopic characteristics of opacified IOLs. Glistenings and subsurface nanoglistenings are fluid-related phenomena developing mainly in hydrophobic acrylic IOLs and are associated with aqueous influx into the IOL matrix. Calcification presents in hydrophilic acrylic or silicone IOLs as deposits of hydroxyapatite or other phases of calcium. Snowflake degeneration is less common, and it manifests in older polymethyl methacrylate IOLs. PubMed and ScienceDirect databases were searched for the following keywords: intraocular lens, IOL, cataract surgery, phacoemulsification, opacification, glistening, subsurface nanoglistenings, calcification, snowflake degeneration. English-language articles published up to October 15, 2019 were included in the study. The manuscript contains mainly a literature review; however, it was supplemented with original investigations from the David J. Apple International Laboratory for Ocular Pathology. Glistenings and subsurface nanoglistenings should be evaluated in a hydrated state and at room temperature; they manifest as microvacuoles sized from 1.0 to greater than 25.0 μm and less than 200 nm, respectively. Calcification deposits are situated on or underneath the surface of the IOL and can be stained with a 1% alizarin red solution or with the von Kossa method. Snowflake degeneration manifests as "particles" or "crystals," causing whitish IOL discoloration. Scanning electron microscopy or energy dispersive X-ray spectroscopy may improve the diagnostic accuracy.

Comparison of polymethylmethacrylate versus hydrophobic acrylic lenses for primary intraocular lens implantation in pediatric cataract surgery

AIM: To compare the visual results and postoperative complications of polymethylmethacrylate (PMMA) and hydrophobic acrylic intraocular lenses (IOLs) in children who underwent cataract extraction with primary IOL implantation. METHODS: This retrospective study included 117 eyes of 63 children with bilateral pediatric cataract undergoing cataract surgery and primary IOL implantation. The patients were divided into two groups, Group I included 58 eyes of 30 patients with PMMA IOLs; Group II included 59 eyes of 33 patients with hydrophobic acrylic IOLs. The clinical features, refraction errors, best corrected visual acuity (BCVA) and surgical complications were compared between two groups. RESULTS: The mean age at the time of surgery was 5.8 (2-12)y and mean follow up period was 40.5 (6-196)mo. Postoperatively, BCVA was ≥0.5 in 80 eyes (68.4%) and this was comparable in two groups. Visual axis opacification was seen in 28 eyes (48.3%) in Group I and 16 eyes (27.1%) in Group II and this difference was statistically significant (P=0.018). Postoperative IOL dislocation and posterior synechia formation were also noted. When all postoperative complications were considered, there were significantly less complications in the acrylic IOL group than PMMA IOL group (P=0.020). CONCLUSION: Pediatric cataract surgery with primary IOL implantation is a safe procedure. Hydrophobic acrylic IOLs may lead to less postoperative complications compared to PMMA IOLs.

Modified Intrascleral Fixation for Repositioning the Dislocated Single-Piece, Rigid PMMA Intraocular Lens.

To describe a modified intrascleral fixation technique for repositioning single-piece rigid polymethyl methacrylate intraocular lenses (IOLs). Four patients with dislocated IOLs were enrolled. Surgical modifications included using ≤1-mm scleral incision for haptic externalization, placing the IOL haptic placement in scleral tunnels, and using 8-0 absorbable sutures. Patients were followed up for 6 months with routine ophthalmic examinations, corneal endothelial cell counts, and ultrasound biomicroscopy (UBM). The mean follow-up time was 13.5 ± 5.45 months. The IOL was well centered and the spherical refraction improved (+10.25 ± 2.21 vs. -0.81 ± 1.59 D, P < 0.05), whereas the best-corrected visual acuity (pre 20/43 Snellen, 0.42 ± 0.33 logarithm of the minimum angle of resolution equivalent and post 20/36 Snellen, 0.31 ± 0.22 logarithm of the minimum angle of resolution equivalent; P = 0.235), intraocular pressure (pre 13.8 ± 3.21, post 13.55 ± 5.14 mmHg), corneal endothelium density (pre 2,423.8 ± 279.6/mm 2 , post 2,280.25 ± 350.7/mm 2 ), and total astigmatism (pre -1.94 ± 0.43, post -1.69 ± 0.59 D) remained unchanged. The average horizontal and vertical IOL tilt was 0.33 ± 0.22° and 0.81 ± 0.38°, respectively. Intraocular lens decentration was 0.10 ± 0.03 mm horizontally and 0.13 ± 0.06 mm vertically. The modified intrascleral fixation technique shows encouraging midterm results in patients with dislocated single-piece, rigid polymethyl methacrylate IOLs. Larger samples and longer follow-up are required to confirm the outcomes of this technique.