Surface Of Intraocular Lens Research Articles

Preclinical evaluation on the biocompatibility and biosafety of a new foldable brown‐diaphragm intraocular lens: an in vitro and in vivo study

Aims/Purpose: A new foldable brown‐diaphragm intraocular lens (IOL) was preclinically evaluated in vitro and in vivo by comparing its biocompatibility and biosafety with those of a commercially available IOL.Methods: The new brown‐diaphragm IOL is made of hydrophobic acrylic material, with incorporating a transparent optical zone and surrounding brown diaphragm. Cellular experiments evaluating lens epithelial cell morphology, adhesion, and migration were conducted to exclude cytotoxic effects. Twelve New Zealand rabbits had the new brown‐diaphragm IOL implanted in one eye and another 12 had a commercially available foldable IOL implanted, followed by slit‐lamp evaluations, corneal endothelial cells density measurement and aqueous humor analysis to identify any dye leakage from the brown‐diaphragm IOL. Haematoxylin and eosin staining of ocular tissue and scanning electron microscopy (SEM) of the IOL surface were performed after 12‐week observation.Results: In vivo experiments showed there were no statistically significant differences between the two groups in terms of postoperative inflammation and capsular biocompatibility. There were no significant changes in corneal endothelial cell density between before and after surgery in either group. LC‐MS/MS analysis showed that the target dye was not detected in aqueous humor samples. Histopathology of ocular sections and SEM imaging of IOL surfaces showed similar changes in both groups.Conclusions: The newly‐invented brown‐diaphragm IOL showed good biocompatibility and biosafety. Combined with its foldability and peripheral shading, it could be a new choice for patients with iris defects.

Preclinical evaluation on the biocompatibility and biosafety of a new foldable brown‐diaphragm intraocular lens: An in vitro and in vivo study

Aims/Purpose: A new foldable brown‐diaphragm intraocular lens (IOL) was preclinically evaluated in vitro and in vivo by comparing its biocompatibility and biosafety with those of a commercially available IOL.Methods: The new brown‐diaphragm IOL is made of hydrophobic acrylic material, with incorporating a transparent optical zone and surrounding brown diaphragm. Cellular experiments evaluating lens epithelial cell morphology, adhesion, and migration were conducted to exclude cytotoxic effects. Twelve New Zealand rabbits had the new brown‐diaphragm IOL implanted in one eye and another 12 had a commercially available foldable IOL implanted, followed by slit‐lamp evaluations, corneal endothelial cells density measurement and aqueous humor analysis to identify any dye leakage from the brown‐diaphragm IOL. Haematoxylin and eosin staining of ocular tissue and scanning electron microscopy (SEM) of the IOL surface were performed after 12‐week observation.Results: In vivo experiments showed there were no statistically significant differences between the two groups in terms of postoperative inflammation and capsular biocompatibility. There were no significant changes in corneal endothelial cell density between before and after surgery in either group. LC‐MS/MS analysis showed that the target dye was not detected in aqueous humor samples. Histopathology of ocular sections and SEM imaging of IOL surfaces showed similar changes in both groups.Conclusions: The newly‐invented brown‐diaphragm IOL showed good biocompatibility and biosafety. Combined with its foldability and peripheral shading, it could be a new choice for patients with iris defects.

Evaluation of change in the contact of IOL with the posterior capsule with respect to the orientation of haptics of the IOL using intraoperative spectral domain optical coherence tomography.

To study change in the contact of intraocular lens (IOL) with the posterior capsule with respect to the vertical versus horizontal orientation of the haptic-optic junction of the IOL using intraoperative spectral domain optical coherence tomography (SD-OCT). Fifty eyes of 50 patients with senile immature cataract underwent topical phacoemulsification procedure with implantation of a monofocal IOL by a single experienced surgeon. The Rescan 700 SD-OCT system was used for intraoperative imaging. These patients were imaged using intraoperative SD-OCT after implantation of IOL, with the haptics oriented horizontally and then vertically. The vertical height between the posterior surface of the lens capsule and the posterior surface of IOL reduced significantly when the haptics were oriented vertically compared to horizontal orientation. This difference was found on analyzing both vertical as well as horizontal axis scans. We found a greater contact between the posterior capsule and the posterior surface of IOL, with the haptic optic junction of the IOL oriented vertically. This study also suggests the need for newer toric IOL designs which allow vertical orientation of haptics, leading to better contact between IOL and the bag.

Cascade catalytic multilayer modified intraocular lens for enhanced and safer posterior capsule opacification prevention

Posterior capsule opacification (PCO) is the most common complication after cataract surgery. It is primarily caused by the proliferation, migration, and adhesion of residual lens epithelial cells within the capsular bag following phacoemulsification and intraocular lens (IOL) implantation. Although investigations of surface modification onto IOL have partially reduced PCO development in recent years, there are still challenges in long-term efficacy and intraocular biocompatibility. In this study, a cascade catalytic system is constructed using natural enzymes onto mesoporous silica nanoparticles (MSNs), which are subsequently fixed to the surface of IOL through layer-by-layer self-assemble of alternating positive and negative charges. The cascade catalytic reaction is trigged simply by glucose within the pouch to produce reactive oxygen species (ROS) without introducing any toxic drugs or external energy, attempting to minimize the possible toxic side effects to surrounding tissues. In vivo and in vitro experiments indicate the effective inhibition of PCO and favorable intraocular compatibility of the cascade catalytic platform modified IOL. More importantly, the modified IOL retains good optical performance and imaging quality, demonstrating promising prospects for application. This study provides a new possibility for enhanced and safer PCO prevention, playing great significance in clinical treatment. Statement of SignificanceCascade catalytic nanoparticles-loaded multilayer modified IOL is obtained via LbL technique.The multilayer coating improves both the loading capacity and the activity of the cascade catalytic nanoparticles.The cascade catalytic reaction is trigged by glucose, producing ROS that efficiently induces apoptosis and death of remaining cells on IOL without introducing any toxic drugs or external energy.The innovative IOL provides a promising approach for enhanced and safer prevention of PCO.

Hydroxypropyl methylcellulose remove dense water droplets during fluid-air exchange on the posterior surface of intraocular lenses with posterior capsule loss.

The research investigates the efficacy of hydroxypropyl methylcellulose (HPMC) treatment in facilitating the development of compact water droplets on the rear surface of synthetic lenses with capsule imperfections during the process of fluid-air exchange. This study examined four patients with intraocular lens (IOL) implants and posterior capsule defects who experienced the formation of dense water droplets on the posterior surface following fluid-air exchange. When this occurrence obstructs fundus visualization during surgery, it is recommended to suspend the surgical procedure. Upon removal of the non-contact fundoscope and inspection of the IOL, the presence of dense water droplets becomes evident. Subsequently, the removal of bubbles can be achieved by employing a blunt needle filled with HPMC, which is subsequently administered to the area posterior to the intraocular lens. Subsequently, the HPMC should be uniformly distributed on IOL back surface using the blunt needle. During the surgical procedure, it was noted that all patients attained a clear fundus field of vision after the administration of HPMC and insertion of the IOL, facilitating the successful execution of subsequent surgical procedures. HPMC serves as a suitable viscoelastic agent for the elimination of dense water droplets adhered to the surface of intraocular lenses following application, consequently maintaining a clear visual field of the fundus. This surgical intervention is characterized by its efficacy and safety.

Through-focus performance and off-axis effects in aspheric monofocal intraocular lenses.

This study aimed to determine the through-focus performance and the effect of misalignment on the optical quality of different aspheric monofocal intraocular lenses (IOLs). To this end, optical quality was assessed in three IOL models with different optic surfaces: standard aberration neutral model and two spherical aberration (SA) correcting, one of which utilizes higher-order aspheric terms. The optical quality was measured by means of the modulation transfer function at 3- and 4.5-mm pupils and under monochromatic and polychromatic light with different corneal SA. The optically derived range of vision and tolerance to misalignment were also tested. The study demonstrated that the type of IOL surface affects the monofocal implant's performance. Although a standard primary-SA correction may improve scotopic image quality, misalignment may diminish this advantage. The higher-order aspheric surface used to correct SA provided an improved performance against decentration and offered a higher optical quality than the aberration-neutral design when tested in a model eye. The latter, however, demonstrated a high tolerance to misalignment, offering a slight extension of the range of vision, potentially resulting from uncorrected optical aberrations.

Higher phosphate concentrations as in aqueous humor of diabetic patients increase intraocular lens calcification

BackgroundClinical evidence suggests an association between phosphate concentrations in aqueous humor and the risk of intraocular lens (IOL) calcification. To test this hypothesis the influence of different phosphate concentrations on IOL calcification was evaluated in an in vitro electrophoresis model.Methods20 IOLs of two hydrophilic IOL models (CT Spheris 204, Zeiss; Lentis L-313, Oculentis) and one hydrophobic control IOL model (Clareon CNA0T0, Alcon) were exposed to physiologic and elevated phosphate concentrations, similar to diabetic aqueous humor. IOL calcification was analyzed by alizarin red staining, von Kossa staining, scanning electron microscopy, energy dispersive x-ray spectroscopy and transmission electron microscopy with electron diffraction.ResultsHigher phosphate concentrations were associated with IOL calcification. Analyses of IOL surfaces and cross-sections documented calcification in no CT Spheris and 4 Lentis IOLs following exposure to 10 mM Na2HPO4, compared with 7 and 11 positive analyses following exposure to 14 mM Na2HPO4, respectively. Furthermore, a clear association between IOL calcification and the duration of electrophoresis was demonstrated, confirming increased phosphate concentrations and duration of exposure as risk factors of IOL calcification.ConclusionsFindings suggest that higher phosphate concentrations in aqueous humor, as seen in diabetic patients, contribute to an increased IOL calcification risk, potentially explaining clinical observations showing an increased risk of IOL calcification in patients with diabetes.

Laser Processing of Intraocular Lenses

Polymeric Intraocular lenses (IOLs) are vital for restoring vision following cataract surgery and for correcting refractive errors. Despite technological and medical advancements, challenges persist in achieving optimal vision and preventing complications. Surface modifications aim to mitigate the risk of posterior capsule opacification (PCO), while pre-operative measurements aid in selecting suitable IOLs. However, individualized solutions are lacking and there is a clear demand for the development of fully customized IOL surfaces. We employ laser micromachining technology for precise modifications via ablation on PMMA and acrylic IOLs, using femtosecond (fs), nanosecond (ns), and diode continuous wave (CW) lasers, at wavelengths ranging from near-ultraviolet to infrared. Characterization reveals controlled ablation patterning, achieving feature sizes from as small as 400 nm to several micrometers. Regular and confocal micro-Raman spectroscopy revealed alterations of the IOL materials’ structural integrity for some patterning cases, thus affecting the optical properties, while these can be minimized by the proper selection of micromachining conditions. The results suggest the feasibility of accurate IOL patterning, which could offer personalized vision correction solutions, based on relevant corneal wavefront data, thus surpassing standard lenses, marking a significant advancement in cataract surgery outcomes.

Implantation of phakic intraocular lenses in patients with stabilized keratoconus

To date, extensive experience has been accumulated in the correction of high myopia and myopic astigmatism through the implantation of additional negative lenses (phakic intraocular lenses). However, the use of this method in patients with anatomically altered corneas due to keratoconus remains unresolved.Purpose: to assess the effectiveness and safety of correcting high myopia combined with myopic astigmatism by implanting phakic intraocular lenses in patients with stabilized keratoconus at stages 1–2.Materials and methods. The study encompassed results from 27 surgeries involving the implantation of phakic intraocular lenses in patients with high myopia and myopic astigmatism (12.63 ± 4.25 D). These patients had thin corneas and were diagnosed with stage 1–2 keratoconus after undergoing corneal collagen crosslinking treatment – this constituted the main group. The control group comprised 35 surgeries performed on patients with subclinical non-progressive keratoconus (Forme Fruste). All participants underwent evaluations for visual acuity dynamics and refractive stability of spherical and cylindrical components before surgery, immediately post-surgery, and then at 1, 6, and 12 months after implantation. Additional assessments included intraocular pressure measurements, gonioscopy, ultrasonic echobiometry, ultrasonic ophthalmoscopy, biomicroscopy, ophthalmoscopy, endothelial microscopy, vision character and stereopsis determination, ultrasound biomicroscopy, anterior segment optical coherence tomography, electrophysiological studies, and statistical analysis. An IPCL (a type of phakic intraocular lenses made from hydrophilic acrylic) was implanted, capable of correcting myopia up to 30 D and astigmatism up to 10 D.Results. All patients achieved high uncorrected visual acuity 0.86 ± 0.11. Astigmatism correction was successful in 96% of cases. The average postoperative vault – the distance from the back surface of the phakic intraocular lenses to the anterior lens capsule – was 527.5 ± 40.27 μm (range 460–600 μm), and the intraocular pressure was 11.7 ± 2.08 mm Hg. There was a minor decrease in corneal endothelial cell count from 2599 ± 157.3 to 2375 ± 125.3 cells/mm² in the first group and from 2614 ± 104.8 to 2375 ± 43.3 cells/mm² in the second group respectively (p > 0.05), which falls within the acceptable loss range of 4–7% from preoperative values for both groups. Throughout the observation period, there were no cases of cataract development, pigmentary glaucoma, pupillary block, or other vision-threatening complications.Conclusions. Implantation of phakic intraocular lenses in patients with early-stage stabilized keratoconus and subclinical non-progressive keratoconus provides an effective and practically safe means of correcting high myopia and astigmatism.

Comparison of the effect of capsular bend on the rotational stability between 2 toric intraocular lenses.

To compare the effect of capsular bend on the rotational stability between 2 toric intraocular lenses (IOLs). Eye Hospital of Wenzhou Medical University, Hangzhou, Zhejiang Province, China. Prospective study. Patients with preexisting astigmatism received AcrySof IQ (SN6AT) or TECNIS (ZCT/ZMT) toric IOL during cataract surgery. CASIA2 was used to record the toric IOL axial orientation and capsular bend index (CBI) at the 1-day, 1-week, 1-month, and 3-month interval postoperatively. The postoperative rotational stability and CBI of both models were compared. A total of 58 eyes from 58 patients were enrolled in this study. The total misalignment of the TECNIS (ZCT/ZMT) group (6.96 ± 5.10 degrees, 7.41 ± 5.19 degrees, 6.93 ± 5.29 degrees, and 6.86 ± 5. 27 degrees) was significantly higher than that of the AcrySof IQ (SN6AT) group (3.55 ± 2.21 degrees, 4.00 ± 2.74 degrees, 3.72 ± 2.72 degrees, and 3.52 ± 2.50 degrees) at all follow-up intervals ( P < .05). The mean rotation of the TECNIS (ZCT/ZMT) group (2.66 ± 2.18 degrees) was significantly greater than that of the AcrySof IQ (SN6AT) group (1.65 ± 1.47 degrees) from 1 day to 1 week postoperatively ( P < .05). The capsular bend formation in the TECNIS (ZCT/ZMT) group was delayed compared with the AcrySof IQ (SN6AT) group ( P < .05, at the 1-week, 1-month, and 3-month interval). The TECNIS (ZCT/ZMT) group showed fibrosis in the peripheral anterior capsule, leading to its stretching away from the IOL surface, while the AcrySof IQ (SN6AT) group exhibited gentle adherence of the anterior capsule to the IOL surface. The AcrySof IQ toric IOL (SN6AT) exhibited greater rotational stability than the TECNIS toric IOL (ZCT/ZMT), which may partially result from the delay in capsular bend formation of TECNIS at the 1-day to 1-week follow-up postoperatively.

Clinical performance and shape analysis of trifocal intraocular lenses via scanning electron microscopy

BackgroundTo evaluate visual performance after implantation of the TFNT (Acrysof Panoptix, Alcon, Fort Worth, Texas, USA) and CNWT (Clareon Panoptix, Alcon, Fort Worth, Texas, USA) intraocular lens (IOL), and compare the lens shape observed by scanning electron microscope (SEM).MethodsEighteen patients (18 eyes) received implantation of the CNWT and Twenty patients (20 eyes) received implantation of the TFNT. Exclusion criteria were previous ocular surgeries, ocular pathologies, or corneal abnormalities. Intervention or Observational Procedure(s): Postoperative examination at 1 months including manifest refraction; evaluation of refractive error, distance-corrected visual acuity (DCVA) at 5 m, 1 m, 70 cm, 50 cm, 40 cm, and 30 cm, slit-lamp examination; defocus curve testing; contrast sensitivity (CS) was performed. The lens shape of the TFNT and the CNWT was examined under SEM.ResultsMean spherical equivalent was 0.11 ± 0.41 D (CNWT group) and 0.12 ± 0.34 D (TFNT group) 1 month postoperation. DCVA and defocus curve showed no significant difference between the two groups. CS was significantly higher in CNWT group than TFNT group at spatial frequencies of 6 cycles per degree (cpd). Observation of the IOL with a scanning electron microscope (SEM) revealed that CNWT group had improved diffraction structure and edge processing accuracy compared to TFNT group.ConclusionThere was no significant difference between the two groups in the defocus curve and visual acuity at all distances. CS was better in the CNWT group than in the TFNT group. IOL surface features may affect CS.

Long-term Prevalence of Opacification of a Hydrophylic Acrylic Rotationally Asymmetric Refractive Multifocal Intraocular Lens.

To determine the prevalence of opacification of a hydrophylic intraocular lens (IOL) with hydrophobic coverage and the percentage of explantations required, determining possible risk factors associated with these opacifications. This ambispective study enrolled 575 eyes of 296 patients (age 36 to 87 years) that underwent cataract surgery between 2010 and 2017 with implantation of different models of Lentis Mplus IOLs: LS-312-MF30, LS-313-MF15, LS-313-MF30, LU-313-MF30, and LU-313-MF30T (Oculentis GmbH). Visual, refractive, and slit-lamp biomicroscopic changes were evaluated in a long-term follow-up. The percentage of cases with IOL opacification and the percentage of cases in which IOL explantation was required due to such opacifications were calculated at each visit. Five of the explanted IOLs from this series could be analyzed by scanning electron microscopy (SEM-EDX). IOL opacification developed in 63 eyes (11.0%). With 95% confidence, the prevalence of IOL opacification was between 842 and 1,401 cases per 10,000 eyes. The time elapsed between surgery and the presence of IOL opacification ranged between 0 and 9.3 years (mean: 4.7 ± 2.2 years). No significant differences in terms of IOL opacification rate were found according to gender (P = .378). No significant differences were found in arterial hypertension, diabetes, hypothyroidism, or hyperthyroidism rates between eyes with or without IOL opacification (P ≥ .053). IOL explantation was needed in 9 eyes (1.57%). SEM-EDX analysis confirmed the presence of rough areas on the IOL surface containing different components, such as calcium, phosphorous, copper, or nitrogen. The prevalence of opacification with time in Lentis Mplus IOLs is high, with no systemic risk factors associated with this complication, suggesting that it may be attributable to the material and/or the manufacturing process. [J Refract Surg. 2024;40(2):e98-e107.].

Self-assembled coating with a metal-polyphenolic network for intraocular lens modification to prevent posterior capsule opacification

Posterior capsule opacification (PCO) is a main complication after cataract surgery and intraocular lens (IOLs) implantation and is attributed to residual lens epithelial cells (LECs) migrating to the IOL surface and posterior capsules. IOL surface modification has been a newly-developing research filed in recent years; however, the applicability and economical acquisition of modified materials remain unsolved. In this study, we first applied a metal-polyphenolic network coating with a self-assembly technique on the IOL surface by using tannic acid (TA) combined with AlCl3, which are easily acquire and applying on the IOL surface to solve the IOL transmittance affair. Using wound healing and Transwell assay to verify AZD0364 inhibits cell migration ( P < 0.05), the lipopolysaccharide-induced macrophage inflammation model to verify pterostilbene (PTE) inhibits the inflammatory reaction ( P < 0.01). By optimizes its self-assembly coating parameters and calculating its drug release kinetics, we successfully loaded these two drugs on the coating, named TA (AZD0364/PTE) IOL. Its surface morphology characteristics were analyzed by scanning electron microscope, x-ray photoelectron spectrometer and water contact angle. The optical performance was carefully investigated by optical instruments and equipment (n= 3). The in vitro results showed that TA (AZD0364/PTE) IOL can significantly inhibit cell adhesion and acute inflammation (n= 3, P < 0.0001). Importantly, after in vivo implantation for 28 d with eight rabbits PCO models in two groups, the TA (AZD0364/PTE) IOL group maintained clear refracting media and decreased the inflammatory reaction compared with the original IOL group ( P < 0.05). This study provides a new applicable and economical strategy for preventing PCO and offers a reference for the next generation of IOLs that benefit cataract patients.

Material Analysis of Explanted Calcified Silicone Intraocular Lenses in Association with Asteroid Hyalosis.

The aim of this study was to analyze posterior surface opacification in explanted silicone intraocular lenses (IOLs) with clinicopathologic correlation to asteroid hyalosis. In a laboratory setup, 12 explanted silicone IOLs underwent laboratory analyses, including light microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy for elemental composition (EDX). Relevant clinical data were obtained for each case, including gender, age at IOL implantation, dates of implantation and explantation, as well as history of neodymium-dopped yttrium aluminum garnet (Nd:YAG) laser treatments or other opacification removal attempts. High-resolution optical coherence tomography (OCT) images were obtained in vitro with an anterior segment OCT device (Anterion, Heidelberg Engineering, Heidelberg, Germany). Calcification located at the posterior optic surface of each lens was identified through SEM and EDX analyses, revealing deposits composed of hydroxyapatite. In all cases, IOL polishing using Nd:YAG laser had been attempted prior to IOL exchange. The clinical functional data showed that this type of IOL opacity led to increase in straylight and subjective symptoms of glare. Silicone IOLs can develop posterior surface calcification in eyes with asteroid hyalosis. There are mechanical techniques of cleaning the IOL surface but in many cases, IOL explantation is the only sustainable way to reduce the patients' straylight levels and glare symptoms. Due to the risk of posterior surface calcification, silicone IOL implantation should be avoided in eyes with asteroid hyalosis.

The human capsular bag model as a pre‐clinical evaluation tool for IOLs

Cataract affects the vision and well‐being of millions. At present the only means of treating cataract is through surgical intervention. Modern cataract surgery typically retains a ring of anterior lens capsule and the entire posterior capsule. This is known as a capsular bag, which can house an intraocular lens (IOL) implant. Initial surgical outcomes are excellent, but with time lens cells that remain following surgery undergo a wound‐healing response. In essence the trauma of surgery provokes cells to proliferate and migrate across the acellular capsular surfaces and in some case the IOL surface. Most importantly, cells ultimately grow within the visual axis, on the central posterior capsule, and undergo fibrotic events that are associated with transdifferentiation to myofibroblasts, matrix deposition and matrix contraction that can lead to a secondary loss of vision termed posterior capsule opacification (PCO). PCO affects a large proportion of patients and is one of the most common fibrotic conditions in the world. It is therefore of great importance to better understand this condition and thus strong experimental systems are required for this purpose. To this end cataract surgery can be performed on human donor eyes within a laboratory setting to provide a biological product that is configured in the same manner as in the patient. This is known as the human capsular bag model. Using this clinically relevant model it has been possible to tease our key regulatory molecules driving human lens growth and fibrosis. While the human capsular bag model has been a useful tool to identify therapeutic targets or test putative therapeutics no pharmacological treatment is currently in clinical use. As a result, the intraocular lens is currently the major tool employed to manage PCO progression. Characteristics required for an IOL include strong optical performance, stability within the lens capsular bag and anti‐PCO properties. To meet international standards for IOL manufacture a number of tests are performed to predict IOL behaviour when implanted. However, ISO guided tests take place in a non‐biological setting and are limited to assessing purely physical characteristics. Therefore, understanding how the IOL interacts with the capsular bag and how wound‐healing responses could influence IOL position and stability is an area of great importance. The human capsular bag model can address this shortfall in the IOL development pipeline to relate design features to IOL stability and anti‐PCO performance in a clinically relevant setting. The presentation will highlight the evolution of the model as a tool for IOL testing and development.

Corneal asphericity and its related factors.

Proper correction of spherical aberration using intraocular lenses requires precise selection of the sphericity of intraocular lens surfaces based on individual biometric data and corneal asphericity coefficient (Q value). This study aimed to determine and analyze the corneal Q value and its related factors among Saudi participants. In this cross-sectional study, normal right eyes of healthy Saudi participants aged 17 - 58 years who visited Al-Kahhal Medical Complex, Dammam, Saudi Arabia, were included. The Pentacam rotating Scheimpflug camera was used to determine the average Q value at 6-mm diameter. Q values were obtained from each quadrant (superior, nasal, inferior, and temporal) and two meridians (horizontal and vertical). Mean Q values of the anterior and posterior corneal surfaces were also obtained. Other factors including age, sex, refractive error, and central corneal radius were documented. Five hundred right eyes from 500 participants were included. The mean (standard deviation [SD]) (range) age was 27.2 (7.1) (18 - 58) years. The mean (SD) (range) Q value of 500 eyes was - 0.24 (0.10) (- 0.71 to + 0.09) anteriorly and - 0.16 (0.14) (- 0.70 to + 0.23) posteriorly, being significantly more prolate anteriorly (P < 0.05). The corneas were significantly more prolate in the nasal than in the temporal quadrant, in the superior than in the inferior quadrant, and in the horizontal than in the vertical meridian (all P < 0.05). There were statistically significant differences in anterior, nasal, temporal, inferior, horizontal, and vertical Q values among age groups (all P < 0.05) but not in the superior or posterior Q values (both P > 0.05). The corneas became less prolate with increasing age (P < 0.05). However, Q values were comparable between the sexes (all P > 0.05). There was no significant correlation between anterior (r = + 0.08; P = 0.095) or posterior (r = - 0.08; P = 0.092) Q value and spherical equivalent, but a significant trend was detected toward more prolate shape with increasing myopia in the temporal and inferior quadrants (r = + 0.19; P < 0.001, r = + 0.10; P = 0.022, respectively). There was a significant negligible correlation between the posterior Q value and central corneal radius (r = - 0.18; P < 0.001) but no significant correlation between the anterior Q value and central corneal radius (r = + 0.02; P = 0.673). Most corneas in this Saudi population were prolate in contour. Anterior corneal asphericity was positively correlated with age and was not significantly related to sex, refractive error, or central corneal radius. Further studies are needed to verify our preliminary findings.

Физико-химический анализ гидрофильных интраокулярных линз, эксплантированных в связи с помутнением материала

Relevance. Clouding and discoloration of intraocular lens (IOL) seems to be a multifactorial problem, directly related to the properties of each group of materials from which they are made. Since the exact combination of factors and the sequence of events are not yet fully known, there is reason to continue research in this direction, even though, unfortunately, such important points as the specifics of IOL production are information closed to the general public. It is also obvious that this problem is urgent and requires an integrated approach. Purpose. To determine the type of deposits on the surface of hydrophilic IOLs explanted due to a decrease in the transparency of the material. Material and methods. Visualization of the surface of 8 explanted hydrophilic IOLs was carried out in a digital inverted microscope Altami INVERT 3 (LLC Altami, Russia). Elemental analysis of surface deposits was carried out on a JCM-6000 electron microscope (Jeol, Japan) with a JED-2300 energy dispersive analysis attachment. The Raman spectra were measured using M532 Raman microscope (Enspectr, USA). Infrared absorption spectra (IR spectra) were recorded using equipment: Fourier spectrometer InfraLum FT-02 (Lumex, Russia) and an IR spectrometer with an attachment of frustrated total internal reflection IRTracer-100 (Shimadzu, Japan). The processing and interpretation of the obtained spectra was carried out using databases and software from the equipment. Results. The nature of the deposits is represented by various crystallites, in some places forming a completely continuous film. The main elements of deposits are carbon, nitrogen, and oxygen. The IR spectrum contains functional groups characteristic of proteins. Conclusion. Deposits on the surface of a cloudy IOL of a hydrophilic type are of protein nature. The fact that the deposits have a crystalline structure makes it possible to significantly narrow the scope of the search for those compounds that are capable of crystallizing at temperatures close to the normal temperature of the human body. Key words: IOL clouding, hydrophilic IOL, IOL explantation

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 &amp; Lomb), PFOS (perfluorodecalin) Dk-line (Bausch &amp; 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.

Novel exploration of ions and fatty acids in hydrophilic acrylic intraocular lens calcification.

To conduct a novel exploration and analysis of the ion and fatty acid levels of a medium in which calcified hydrophilic intraocular lenses (IOLs) are present. Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China. Retrospective, laboratory observational case series. Eleven patients (11 eyes) who had implantation of foldable hydrogel posterior IOLs were found to have opacification of the IOLs. In vivo and in vitro analyses included the evaluation of patients' clinical characteristics, microscopy, histological staining, energy dispersive X-ray spectroscopy (EDS), the ion level of the aqueous humor (AH) and preserving fluid (PF), and the fatty acid content of AH. Ten of 11 cases were female with unilateral opacification, and seven cases had both-eye cataract surgery, including 1 first eye and 6 second eyes with IOL opacification. Four types of similar serial numbers were counted. The analysis of AH showed that the concentrations of phosphorus and silicon were elevated but that of calcium decreased, and an increased level of silicon was detected in three random PFs. The palmitic (C16:0) and stearic (C18:0) fatty acids were higher than the others in the AH. The EDS confirmed that the IOL surface deposits were composed of calcium, phosphate, and a small amount of silicon. More silicon and higher C16:0 and C18:0 were found in the AH of patients with IOL opacification. New ideas and avenues have been proposed in the study of IOL opacification.

Inhibition of anterior capsule opacification and contraction by the elevated anterior rim of the intraocular lens optic.

To verify the anterior capsule opacification (ACO) and contraction (ACC) of the ZCB00V intraocular lens (IOL), made of the same material as the AR40e with a high ACC rate. Retrospective cohort study. We evaluated 35 patients at 1 week, 1, 3 and 6 months post phacoemulsification with either a ZCB00V (n = 35) or FY-60AD (n = 34) IOL implantation. The ACC rate was calculated using retroillumination images of the anterior segment, and the ACO was measured using anterior segment photographs and image analysis software. The contact grade between the IOL and anterior capsule was estimated from the Pentacam® images. The postoperative ACC rates (mean ± standard deviation) at 3 months were 1.03%±2.54% for the ZCB00V and, and 7.12%±9.47% for the FY-60AD. The ZCB00V-implanted eyes showed a significantly lower postoperative ACC at 1 week, 3 months, and 6 months (P < 0.01). On the other hand, the FY-60AD-implanted eyes had more pronounced ACO, and a significantly larger area of opacification (62.24%±21.32% vs. 16.90%±8.34%; P = 0.0005). Pentacam® analysis revealed a space between the anterior capsule and IOL surface in the ZCB00V-implanted eyes, whereas the anterior capsule firmly adhered to the IOL surface in the FY-60AD-implanted eyes. The ACC and ACO were significantly lower in eyes with ZCB00V IOLs compared to those with the FY-60AD. The anterior segment image analysis revealed that the elevated anterior rim of the ZCB00V IOL prevented adhesion between the anterior capsule and IOL optic surface, suggesting an open capsule effect.